release: v1.2.0

### Explanation

_No response_

### Issue

Closes #102

### Attestations

- [ ] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [ ] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [ ] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [ ] I have pinned the dependencies to a specific patch version.

### Style

- [ ] I have run the linter and resolved any errors.
- [ ] My pull request uses an appropriate title, matching the conventional commit standards.
- [ ] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [ ] All new and existing tests pass locally with my changes.
- [ ] Code coverage remains at or above the configured threshold.

### Documentation

_No response_

### Versioning

_No response_

Reviewed-on: #103
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

README.md

@@ -1 +1,29 @@
-tem
+# hikari-desktop
+
+Desktop companion application featuring Hikari.
+
+## Live Version
+
+This page is currently deployed. [View the live website.](https://git.nhcarrigan.com/nhcarrigan/hikari-desktop/releases)
+
+## Feedback and Bugs
+
+If you have feedback or a bug report, please [log a ticket on our forum](https://support.nhcarrigan.com).
+
+## Contributing
+
+If you would like to contribute to the project, you may create a Pull Request containing your proposed changes and we will review it as soon as we are able! Please review our [contributing guidelines](CONTRIBUTING.md) first.
+
+## Code of Conduct
+
+Before interacting with our community, please read our [Code of Conduct](CODE_OF_CONDUCT.md).
+
+## License
+
+This software is licensed under our [global software license](https://docs.nhcarrigan.com/#/license).
+
+Copyright held by Naomi Carrigan.
+
+## Contact
+
+We may be contacted through our [Chat Server](http://chat.nhcarrigan.com) or via email at `contact@nhcarrigan.com`

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hikari-desktop",
-  "version": "1.0.0",
+  "version": "1.2.0",
   "description": "",
   "type": "module",
   "scripts": {
@@ -27,6 +27,32 @@
   },
   "license": "MIT",
   "dependencies": {
+    "@codemirror/commands": "6.8.1",
+    "@codemirror/lang-angular": "^0.1.4",
+    "@codemirror/lang-cpp": "^6.0.3",
+    "@codemirror/lang-css": "^6.3.1",
+    "@codemirror/lang-go": "^6.0.1",
+    "@codemirror/lang-html": "^6.4.11",
+    "@codemirror/lang-java": "^6.0.2",
+    "@codemirror/lang-javascript": "^6.2.4",
+    "@codemirror/lang-json": "^6.0.2",
+    "@codemirror/lang-less": "^6.0.2",
+    "@codemirror/lang-markdown": "^6.5.0",
+    "@codemirror/lang-php": "^6.0.2",
+    "@codemirror/lang-python": "^6.2.1",
+    "@codemirror/lang-rust": "^6.0.2",
+    "@codemirror/lang-sass": "^6.0.2",
+    "@codemirror/lang-sql": "^6.10.0",
+    "@codemirror/lang-vue": "^0.1.3",
+    "@codemirror/lang-wast": "^6.0.2",
+    "@codemirror/lang-xml": "^6.1.0",
+    "@codemirror/lang-yaml": "^6.1.2",
+    "@codemirror/language": "^6.12.1",
+    "@codemirror/legacy-modes": "^6.5.2",
+    "@codemirror/state": "^6.5.4",
+    "@codemirror/theme-one-dark": "^6.1.3",
+    "@codemirror/view": "^6.39.11",
+    "@lezer/highlight": "^1.2.3",
     "@tauri-apps/api": "^2",
     "@tauri-apps/plugin-clipboard-manager": "^2.3.2",
     "@tauri-apps/plugin-dialog": "^2",
@@ -36,6 +62,7 @@
     "@tauri-apps/plugin-os": "^2",
     "@tauri-apps/plugin-shell": "^2.3.4",
     "@tauri-apps/plugin-store": "^2",
+    "codemirror": "^6.0.2",
     "highlight.js": "^11.11.1",
     "marked": "^17.0.1"
   },

pnpm-lock.yaml

@@ -8,6 +8,84 @@ importers:
 
   .:
     dependencies:
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+        specifier: 6.8.1
+        version: 6.8.1
+      '@codemirror/lang-angular':
+        specifier: ^0.1.4
+        version: 0.1.4
+      '@codemirror/lang-cpp':
+        specifier: ^6.0.3
+        version: 6.0.3
+      '@codemirror/lang-css':
+        specifier: ^6.3.1
+        version: 6.3.1
+      '@codemirror/lang-go':
+        specifier: ^6.0.1
+        version: 6.0.1
+      '@codemirror/lang-html':
+        specifier: ^6.4.11
+        version: 6.4.11
+      '@codemirror/lang-java':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-javascript':
+        specifier: ^6.2.4
+        version: 6.2.4
+      '@codemirror/lang-json':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-less':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-markdown':
+        specifier: ^6.5.0
+        version: 6.5.0
+      '@codemirror/lang-php':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-python':
+        specifier: ^6.2.1
+        version: 6.2.1
+      '@codemirror/lang-rust':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-sass':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-sql':
+        specifier: ^6.10.0
+        version: 6.10.0
+      '@codemirror/lang-vue':
+        specifier: ^0.1.3
+        version: 0.1.3
+      '@codemirror/lang-wast':
+        specifier: ^6.0.2
+        version: 6.0.2
+      '@codemirror/lang-xml':
+        specifier: ^6.1.0
+        version: 6.1.0
+      '@codemirror/lang-yaml':
+        specifier: ^6.1.2
+        version: 6.1.2
+      '@codemirror/language':
+        specifier: ^6.12.1
+        version: 6.12.1
+      '@codemirror/legacy-modes':
+        specifier: ^6.5.2
+        version: 6.5.2
+      '@codemirror/state':
+        specifier: ^6.5.4
+        version: 6.5.4
+      '@codemirror/theme-one-dark':
+        specifier: ^6.1.3
+        version: 6.1.3
+      '@codemirror/view':
+        specifier: ^6.39.11
+        version: 6.39.11
+      '@lezer/highlight':
+        specifier: ^1.2.3
+        version: 1.2.3
       '@tauri-apps/api':
         specifier: ^2
         version: 2.9.1
@@ -35,6 +113,9 @@ importers:
       '@tauri-apps/plugin-store':
         specifier: ^2
         version: 2.4.2
+      codemirror:
+        specifier: ^6.0.2
+        version: 6.0.2
       highlight.js:
         specifier: ^11.11.1
         version: 11.11.1
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     engines: {node: '>=18'}
 
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+
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+
+  '@codemirror/lang-angular@0.1.4':
+    resolution: {integrity: sha512-oap+gsltb/fzdlTQWD6BFF4bSLKcDnlxDsLdePiJpCVNKWXSTAbiiQeYI3UmES+BLAdkmIC1WjyztC1pi/bX4g==}
+
+  '@codemirror/lang-cpp@6.0.3':
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+
+  '@codemirror/lang-go@6.0.1':
+    resolution: {integrity: sha512-7fNvbyNylvqCphW9HD6WFnRpcDjr+KXX/FgqXy5H5ZS0eC5edDljukm/yNgYkwTsgp2busdod50AOTIy6Jikfg==}
+
+  '@codemirror/lang-html@6.4.11':
+    resolution: {integrity: sha512-9NsXp7Nwp891pQchI7gPdTwBuSuT3K65NGTHWHNJ55HjYcHLllr0rbIZNdOzas9ztc1EUVBlHou85FFZS4BNnw==}
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+  '@codemirror/lang-java@6.0.2':
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+    resolution: {integrity: sha512-EYdQTG22V+KUUk8Qq582g7FMnCZeEHsyuOJisHRft/mQ+ZSZ2w51NupvDUHiqtsOy7It5cHLPGfHQLpMh9bqpQ==}
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+  '@codemirror/lang-rust@6.0.2':
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+  '@codemirror/lang-sass@6.0.2':
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+  '@codemirror/lang-sql@6.10.0':
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+  '@codemirror/lang-vue@0.1.3':
+    resolution: {integrity: sha512-QSKdtYTDRhEHCfo5zOShzxCmqKJvgGrZwDQSdbvCRJ5pRLWBS7pD/8e/tH44aVQT6FKm0t6RVNoSUWHOI5vNug==}
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+  '@codemirror/theme-one-dark@6.1.3':
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     engines: {node: '>=7.0.0'}
@@ -1029,6 +1251,9 @@ packages:
     resolution: {integrity: sha512-U71cyTamuh1CRNCfpGY6to28lxvNwPG4Guz/EVjgf3Jmzv0vlDp1atT9eS5dDjMYHucpHbWns6Lwf3BKz6svdw==}
     engines: {node: '>= 0.6'}
 
+  crelt@1.0.6:
+    resolution: {integrity: sha512-VQ2MBenTq1fWZUH9DJNGti7kKv6EeAuYr3cLwxUWhIu1baTaXh4Ib5W2CqHVqib4/MqbYGJqiL3Zb8GJZr3l4g==}
+
   cross-spawn@7.0.6:
     resolution: {integrity: sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA==}
     engines: {node: '>= 8'}
@@ -1663,6 +1888,9 @@ packages:
     resolution: {integrity: sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==}
     engines: {node: '>=8'}
 
+  style-mod@4.1.3:
+    resolution: {integrity: sha512-i/n8VsZydrugj3Iuzll8+x/00GH2vnYsk1eomD8QiRrSAeW6ItbCQDtfXCeJHd0iwiNagqjQkvpvREEPtW3IoQ==}
+
   supports-color@7.2.0:
     resolution: {integrity: sha512-qpCAvRl9stuOHveKsn7HncJRvv501qIacKzQlO/+Lwxc9+0q2wLyv4Dfvt80/DPn2pqOBsJdDiogXGR9+OvwRw==}
     engines: {node: '>=8'}
@@ -1842,6 +2070,9 @@ packages:
       jsdom:
         optional: true
 
+  w3c-keyname@2.2.8:
+    resolution: {integrity: sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==}
+
   w3c-xmlserializer@5.0.0:
     resolution: {integrity: sha512-o8qghlI8NZHU1lLPrpi2+Uq7abh4GGPpYANlalzWxyWteJOCsr/P+oPBA49TOLu5FTZO4d3F9MnWJfiMo4BkmA==}
     engines: {node: '>=18'}
@@ -1949,6 +2180,216 @@ snapshots:
 
   '@bcoe/v8-coverage@1.0.2': {}
 
+  '@codemirror/autocomplete@6.20.0':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+
+  '@codemirror/commands@6.8.1':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+
+  '@codemirror/lang-angular@0.1.4':
+    dependencies:
+      '@codemirror/lang-html': 6.4.11
+      '@codemirror/lang-javascript': 6.2.4
+      '@codemirror/language': 6.12.1
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@codemirror/lang-cpp@6.0.3':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@lezer/cpp': 1.1.5
+
+  '@codemirror/lang-css@6.3.1':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/css': 1.3.0
+
+  '@codemirror/lang-go@6.0.1':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/go': 1.0.1
+
+  '@codemirror/lang-html@6.4.11':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/lang-css': 6.3.1
+      '@codemirror/lang-javascript': 6.2.4
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+      '@lezer/css': 1.3.0
+      '@lezer/html': 1.3.13
+
+  '@codemirror/lang-java@6.0.2':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@lezer/java': 1.1.3
+
+  '@codemirror/lang-javascript@6.2.4':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/lint': 6.9.3
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+      '@lezer/javascript': 1.5.4
+
+  '@codemirror/lang-json@6.0.2':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@lezer/json': 1.0.3
+
+  '@codemirror/lang-less@6.0.2':
+    dependencies:
+      '@codemirror/lang-css': 6.3.1
+      '@codemirror/language': 6.12.1
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@codemirror/lang-markdown@6.5.0':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/lang-html': 6.4.11
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+      '@lezer/markdown': 1.6.3
+
+  '@codemirror/lang-php@6.0.2':
+    dependencies:
+      '@codemirror/lang-html': 6.4.11
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/php': 1.0.5
+
+  '@codemirror/lang-python@6.2.1':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/python': 1.1.18
+
+  '@codemirror/lang-rust@6.0.2':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@lezer/rust': 1.0.2
+
+  '@codemirror/lang-sass@6.0.2':
+    dependencies:
+      '@codemirror/lang-css': 6.3.1
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/sass': 1.1.0
+
+  '@codemirror/lang-sql@6.10.0':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@codemirror/lang-vue@0.1.3':
+    dependencies:
+      '@codemirror/lang-html': 6.4.11
+      '@codemirror/lang-javascript': 6.2.4
+      '@codemirror/language': 6.12.1
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@codemirror/lang-wast@6.0.2':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@codemirror/lang-xml@6.1.0':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+      '@lezer/xml': 1.0.6
+
+  '@codemirror/lang-yaml@6.1.2':
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+      '@lezer/yaml': 1.0.3
+
+  '@codemirror/language@6.12.1':
+    dependencies:
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+      style-mod: 4.1.3
+
+  '@codemirror/legacy-modes@6.5.2':
+    dependencies:
+      '@codemirror/language': 6.12.1
+
+  '@codemirror/lint@6.9.3':
+    dependencies:
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      crelt: 1.0.6
+
+  '@codemirror/search@6.6.0':
+    dependencies:
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      crelt: 1.0.6
+
+  '@codemirror/state@6.5.4':
+    dependencies:
+      '@marijn/find-cluster-break': 1.0.2
+
+  '@codemirror/theme-one-dark@6.1.3':
+    dependencies:
+      '@codemirror/language': 6.12.1
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+      '@lezer/highlight': 1.2.3
+
+  '@codemirror/view@6.39.11':
+    dependencies:
+      '@codemirror/state': 6.5.4
+      crelt: 1.0.6
+      style-mod: 4.1.3
+      w3c-keyname: 2.2.8
+
   '@csstools/color-helpers@5.1.0': {}
 
   '@csstools/css-calc@2.1.4(@csstools/css-parser-algorithms@3.0.5(@csstools/css-tokenizer@3.0.4))(@csstools/css-tokenizer@3.0.4)':
@@ -2127,6 +2568,101 @@ snapshots:
       '@jridgewell/resolve-uri': 3.1.2
       '@jridgewell/sourcemap-codec': 1.5.5
 
+  '@lezer/common@1.5.0': {}
+
+  '@lezer/cpp@1.1.5':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/css@1.3.0':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/go@1.0.1':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/highlight@1.2.3':
+    dependencies:
+      '@lezer/common': 1.5.0
+
+  '@lezer/html@1.3.13':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/java@1.1.3':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/javascript@1.5.4':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/json@1.0.3':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/lr@1.4.8':
+    dependencies:
+      '@lezer/common': 1.5.0
+
+  '@lezer/markdown@1.6.3':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+
+  '@lezer/php@1.0.5':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/python@1.1.18':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/rust@1.0.2':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/sass@1.1.0':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/xml@1.0.6':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@lezer/yaml@1.0.3':
+    dependencies:
+      '@lezer/common': 1.5.0
+      '@lezer/highlight': 1.2.3
+      '@lezer/lr': 1.4.8
+
+  '@marijn/find-cluster-break@1.0.2': {}
+
   '@polka/url@1.0.0-next.29': {}
 
   '@rollup/rollup-android-arm-eabi@4.55.1':
@@ -2678,6 +3214,16 @@ snapshots:
 
   clsx@2.1.1: {}
 
+  codemirror@6.0.2:
+    dependencies:
+      '@codemirror/autocomplete': 6.20.0
+      '@codemirror/commands': 6.8.1
+      '@codemirror/language': 6.12.1
+      '@codemirror/lint': 6.9.3
+      '@codemirror/search': 6.6.0
+      '@codemirror/state': 6.5.4
+      '@codemirror/view': 6.39.11
+
   color-convert@2.0.1:
     dependencies:
       color-name: 1.1.4
@@ -2688,6 +3234,8 @@ snapshots:
 
   cookie@0.6.0: {}
 
+  crelt@1.0.6: {}
+
   cross-spawn@7.0.6:
     dependencies:
       path-key: 3.1.1
@@ -3304,6 +3852,8 @@ snapshots:
 
   strip-json-comments@3.1.1: {}
 
+  style-mod@4.1.3: {}
+
   supports-color@7.2.0:
     dependencies:
       has-flag: 4.0.0
@@ -3463,6 +4013,8 @@ snapshots:
       - tsx
       - yaml
 
+  w3c-keyname@2.2.8: {}
+
   w3c-xmlserializer@5.0.0:
     dependencies:
       xml-name-validator: 5.0.0

src-tauri/Cargo.lock

@@ -1602,7 +1602,7 @@ checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
 [[package]]
 name = "hikari-desktop"
-version = "0.3.0"
+version = "1.1.1"
 dependencies = [
  "chrono",
  "parking_lot",

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hikari-desktop"
-version = "1.0.0"
+version = "1.2.0"
 description = "Hikari - Claude Code Visual Assistant"
 authors = ["Naomi Carrigan"]
 edition = "2021"

src-tauri/src/achievements.rs

@@ -1935,6 +1935,7 @@ pub fn check_achievements(
     let search_count: u64 = search_tools
         .iter()
         .filter_map(|tool| stats.tools_usage.get(*tool))
+        .map(|t| t.call_count)
         .sum();
     if search_count >= 50 && progress.unlock(AchievementId::Explorer) {
         newly_unlocked.push(AchievementId::Explorer);
@@ -1988,25 +1989,25 @@ pub fn check_achievements(
     // TODO: Track different Claude models used
 
     // Tool mastery achievements
-    if let Some(bash_count) = stats.tools_usage.get("Bash") {
+    if let Some(bash_stats) = stats.tools_usage.get("Bash") {
-        if *bash_count >= 50 && progress.unlock(AchievementId::BashMaster) {
+        if bash_stats.call_count >= 50 && progress.unlock(AchievementId::BashMaster) {
             newly_unlocked.push(AchievementId::BashMaster);
         }
     }
-    if let Some(read_count) = stats.tools_usage.get("Read") {
+    if let Some(read_stats) = stats.tools_usage.get("Read") {
-        if *read_count >= 100 && progress.unlock(AchievementId::FileExplorer) {
+        if read_stats.call_count >= 100 && progress.unlock(AchievementId::FileExplorer) {
             newly_unlocked.push(AchievementId::FileExplorer);
         }
     }
-    if let Some(grep_count) = stats.tools_usage.get("Grep") {
+    if let Some(grep_stats) = stats.tools_usage.get("Grep") {
-        if *grep_count >= 50 && progress.unlock(AchievementId::SearchExpert) {
+        if grep_stats.call_count >= 50 && progress.unlock(AchievementId::SearchExpert) {
             newly_unlocked.push(AchievementId::SearchExpert);
         }
     }
 
     // Git Guru - check git command usage in Bash
-    if let Some(bash_count) = stats.tools_usage.get("Bash") {
+    if let Some(bash_stats) = stats.tools_usage.get("Bash") {
-        if *bash_count >= 10 && progress.unlock(AchievementId::GitGuru) {
+        if bash_stats.call_count >= 10 && progress.unlock(AchievementId::GitGuru) {
             // TODO: More specific git command tracking
             newly_unlocked.push(AchievementId::GitGuru);
         }
@@ -2055,28 +2056,28 @@ pub fn check_achievements(
     }
 
     // More tool mastery achievements
-    if let Some(edit_count) = stats.tools_usage.get("Edit") {
+    if let Some(edit_stats) = stats.tools_usage.get("Edit") {
-        if *edit_count >= 100 && progress.unlock(AchievementId::EditMaster) {
+        if edit_stats.call_count >= 100 && progress.unlock(AchievementId::EditMaster) {
             newly_unlocked.push(AchievementId::EditMaster);
         }
     }
-    if let Some(write_count) = stats.tools_usage.get("Write") {
+    if let Some(write_stats) = stats.tools_usage.get("Write") {
-        if *write_count >= 50 && progress.unlock(AchievementId::WriteMaster) {
+        if write_stats.call_count >= 50 && progress.unlock(AchievementId::WriteMaster) {
             newly_unlocked.push(AchievementId::WriteMaster);
         }
     }
-    if let Some(glob_count) = stats.tools_usage.get("Glob") {
+    if let Some(glob_stats) = stats.tools_usage.get("Glob") {
-        if *glob_count >= 100 && progress.unlock(AchievementId::GlobMaster) {
+        if glob_stats.call_count >= 100 && progress.unlock(AchievementId::GlobMaster) {
             newly_unlocked.push(AchievementId::GlobMaster);
         }
     }
-    if let Some(task_count) = stats.tools_usage.get("Task") {
+    if let Some(task_stats) = stats.tools_usage.get("Task") {
-        if *task_count >= 50 && progress.unlock(AchievementId::TaskMaster) {
+        if task_stats.call_count >= 50 && progress.unlock(AchievementId::TaskMaster) {
             newly_unlocked.push(AchievementId::TaskMaster);
         }
     }
-    if let Some(web_count) = stats.tools_usage.get("WebFetch") {
+    if let Some(web_stats) = stats.tools_usage.get("WebFetch") {
-        if *web_count >= 20 && progress.unlock(AchievementId::WebFetcher) {
+        if web_stats.call_count >= 20 && progress.unlock(AchievementId::WebFetcher) {
             newly_unlocked.push(AchievementId::WebFetcher);
         }
     }
@@ -2085,7 +2086,7 @@ pub fn check_achievements(
         .tools_usage
         .iter()
         .filter(|(name, _)| name.starts_with("mcp__"))
-        .map(|(_, count)| count)
+        .map(|(_, tool_stats)| tool_stats.call_count)
         .sum();
     if mcp_count >= 50 && progress.unlock(AchievementId::McpExplorer) {
         newly_unlocked.push(AchievementId::McpExplorer);
@@ -2323,6 +2324,11 @@ mod tests {
             morning_sessions: 0,
             night_sessions: 0,
             last_session_date: None,
+            context_tokens_used: 0,
+            context_window_limit: 200_000,
+            context_utilisation_percent: 0.0,
+            potential_cache_hits: 0,
+            potential_cache_savings_tokens: 0,
             achievements: AchievementProgress::new(),
         }
     }
@@ -2733,12 +2739,21 @@ mod tests {
     // check_achievements tests - Tool Usage
     // =====================
 
+    // Helper function to create a ToolTokenStats with just call count for tests
+    fn tool_stats(call_count: u64) -> crate::stats::ToolTokenStats {
+        crate::stats::ToolTokenStats {
+            call_count,
+            estimated_input_tokens: 0,
+            estimated_output_tokens: 0,
+        }
+    }
+
     #[test]
     fn test_check_achievements_first_tool() {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Read".to_string(), 1);
+        stats.tools_usage.insert("Read".to_string(), tool_stats(1));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::FirstTool));
@@ -2749,11 +2764,11 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Read".to_string(), 1);
+        stats.tools_usage.insert("Read".to_string(), tool_stats(1));
-        stats.tools_usage.insert("Write".to_string(), 1);
+        stats.tools_usage.insert("Write".to_string(), tool_stats(1));
-        stats.tools_usage.insert("Edit".to_string(), 1);
+        stats.tools_usage.insert("Edit".to_string(), tool_stats(1));
-        stats.tools_usage.insert("Bash".to_string(), 1);
+        stats.tools_usage.insert("Bash".to_string(), tool_stats(1));
-        stats.tools_usage.insert("Grep".to_string(), 1);
+        stats.tools_usage.insert("Grep".to_string(), tool_stats(1));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::Toolsmith));
@@ -2765,7 +2780,7 @@ mod tests {
         let mut progress = AchievementProgress::new();
 
         for i in 0..10 {
-            stats.tools_usage.insert(format!("Tool{}", i), 1);
+            stats.tools_usage.insert(format!("Tool{}", i), tool_stats(1));
         }
 
         let newly = check_achievements(&stats, &mut progress);
@@ -2777,7 +2792,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Bash".to_string(), 50);
+        stats.tools_usage.insert("Bash".to_string(), tool_stats(50));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::BashMaster));
@@ -2788,7 +2803,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Read".to_string(), 100);
+        stats.tools_usage.insert("Read".to_string(), tool_stats(100));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::FileExplorer));
@@ -2799,7 +2814,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Grep".to_string(), 50);
+        stats.tools_usage.insert("Grep".to_string(), tool_stats(50));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::SearchExpert));
@@ -2810,7 +2825,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Edit".to_string(), 100);
+        stats.tools_usage.insert("Edit".to_string(), tool_stats(100));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::EditMaster));
@@ -2821,7 +2836,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Write".to_string(), 50);
+        stats.tools_usage.insert("Write".to_string(), tool_stats(50));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::WriteMaster));
@@ -2832,7 +2847,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Glob".to_string(), 100);
+        stats.tools_usage.insert("Glob".to_string(), tool_stats(100));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::GlobMaster));
@@ -2843,7 +2858,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Task".to_string(), 50);
+        stats.tools_usage.insert("Task".to_string(), tool_stats(50));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::TaskMaster));
@@ -2854,7 +2869,7 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("WebFetch".to_string(), 20);
+        stats.tools_usage.insert("WebFetch".to_string(), tool_stats(20));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::WebFetcher));
@@ -2865,8 +2880,8 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("mcp__github__create_issue".to_string(), 25);
+        stats.tools_usage.insert("mcp__github__create_issue".to_string(), tool_stats(25));
-        stats.tools_usage.insert("mcp__notion__search".to_string(), 25);
+        stats.tools_usage.insert("mcp__notion__search".to_string(), tool_stats(25));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::McpExplorer));
@@ -2881,8 +2896,8 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Grep".to_string(), 30);
+        stats.tools_usage.insert("Grep".to_string(), tool_stats(30));
-        stats.tools_usage.insert("Glob".to_string(), 20);
+        stats.tools_usage.insert("Glob".to_string(), tool_stats(20));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::Explorer));
@@ -2893,9 +2908,9 @@ mod tests {
         let mut stats = create_test_stats();
         let mut progress = AchievementProgress::new();
 
-        stats.tools_usage.insert("Grep".to_string(), 200);
+        stats.tools_usage.insert("Grep".to_string(), tool_stats(200));
-        stats.tools_usage.insert("Glob".to_string(), 200);
+        stats.tools_usage.insert("Glob".to_string(), tool_stats(200));
-        stats.tools_usage.insert("Task".to_string(), 100);
+        stats.tools_usage.insert("Task".to_string(), tool_stats(100));
 
         let newly = check_achievements(&stats, &mut progress);
         assert!(newly.contains(&AchievementId::MasterSearcher));

src-tauri/src/bridge_manager.rs

@@ -3,6 +3,7 @@ use std::collections::HashMap;
 use std::sync::Arc;
 use tauri::AppHandle;
 
+use crate::commands::record_session;
 use crate::config::ClaudeStartOptions;
 use crate::stats::UsageStats;
 use crate::wsl_bridge::WslBridge;
@@ -53,7 +54,12 @@ impl BridgeManager {
             .or_insert_with(|| WslBridge::new_with_conversation_id(conversation_id.to_string()));
 
         // Start the Claude process
-        bridge.start(app, options)?;
+        bridge.start(app.clone(), options)?;
+
+        // Record session start for cost tracking
+        tauri::async_runtime::spawn(async move {
+            record_session(&app).await;
+        });
 
         Ok(())
     }

src-tauri/src/commands.rs

@@ -394,6 +394,259 @@ pub async fn get_file_size(file_path: String) -> Result<u64, String> {
     Ok(metadata.len())
 }
 
+// ==================== Editor File Operations ====================
+
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct FileEntry {
+    pub name: String,
+    pub path: String,
+    #[serde(rename = "isDirectory")]
+    pub is_directory: bool,
+}
+
+#[tauri::command]
+pub async fn list_directory(path: String) -> Result<Vec<FileEntry>, String> {
+    use std::fs;
+    use std::path::Path;
+
+    let dir_path = Path::new(&path);
+
+    if !dir_path.exists() {
+        return Err(format!("Directory does not exist: {}", path));
+    }
+
+    if !dir_path.is_dir() {
+        return Err(format!("Path is not a directory: {}", path));
+    }
+
+    let entries = fs::read_dir(dir_path)
+        .map_err(|e| format!("Failed to read directory: {}", e))?;
+
+    let mut file_entries = Vec::new();
+
+    for entry in entries {
+        let entry = entry.map_err(|e| format!("Failed to read entry: {}", e))?;
+        let path = entry.path();
+        let name = entry
+            .file_name()
+            .to_string_lossy()
+            .to_string();
+
+        // Skip hidden files by default (can be made configurable later)
+        if name.starts_with('.') {
+            continue;
+        }
+
+        file_entries.push(FileEntry {
+            name,
+            path: path.to_string_lossy().to_string(),
+            is_directory: path.is_dir(),
+        });
+    }
+
+    Ok(file_entries)
+}
+
+#[tauri::command]
+pub async fn read_file_content(path: String) -> Result<String, String> {
+    use std::fs;
+
+    fs::read_to_string(&path)
+        .map_err(|e| format!("Failed to read file: {}", e))
+}
+
+#[tauri::command]
+pub async fn write_file_content(path: String, content: String) -> Result<(), String> {
+    use std::fs;
+
+    fs::write(&path, content)
+        .map_err(|e| format!("Failed to write file: {}", e))
+}
+
+#[tauri::command]
+pub async fn create_file(path: String) -> Result<(), String> {
+    use std::fs::File;
+    use std::path::Path;
+
+    let file_path = Path::new(&path);
+
+    if file_path.exists() {
+        return Err("File already exists".to_string());
+    }
+
+    File::create(file_path).map_err(|e| format!("Failed to create file: {}", e))?;
+
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn create_directory(path: String) -> Result<(), String> {
+    use std::fs;
+    use std::path::Path;
+
+    let dir_path = Path::new(&path);
+
+    if dir_path.exists() {
+        return Err("Directory already exists".to_string());
+    }
+
+    fs::create_dir_all(dir_path).map_err(|e| format!("Failed to create directory: {}", e))?;
+
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn delete_file(path: String) -> Result<(), String> {
+    use std::fs;
+    use std::path::Path;
+
+    let file_path = Path::new(&path);
+
+    if !file_path.exists() {
+        return Err("File does not exist".to_string());
+    }
+
+    if file_path.is_dir() {
+        return Err("Path is a directory, use delete_directory instead".to_string());
+    }
+
+    fs::remove_file(file_path).map_err(|e| format!("Failed to delete file: {}", e))?;
+
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn delete_directory(path: String) -> Result<(), String> {
+    use std::fs;
+    use std::path::Path;
+
+    let dir_path = Path::new(&path);
+
+    if !dir_path.exists() {
+        return Err("Directory does not exist".to_string());
+    }
+
+    if !dir_path.is_dir() {
+        return Err("Path is not a directory".to_string());
+    }
+
+    fs::remove_dir_all(dir_path).map_err(|e| format!("Failed to delete directory: {}", e))?;
+
+    Ok(())
+}
+
+#[tauri::command]
+pub async fn rename_path(old_path: String, new_path: String) -> Result<(), String> {
+    use std::fs;
+    use std::path::Path;
+
+    let old = Path::new(&old_path);
+    let new = Path::new(&new_path);
+
+    if !old.exists() {
+        return Err("Path does not exist".to_string());
+    }
+
+    if new.exists() {
+        return Err("Destination already exists".to_string());
+    }
+
+    fs::rename(old, new).map_err(|e| format!("Failed to rename: {}", e))?;
+
+    Ok(())
+}
+
+// ==================== Cost Tracking Commands ====================
+
+const COST_HISTORY_STORE_KEY: &str = "cost_history";
+
+#[tauri::command]
+pub async fn get_cost_summary(app: AppHandle, days: u32) -> Result<crate::cost_tracking::CostSummary, String> {
+    let history = load_cost_history(&app).await;
+    Ok(history.get_summary(days))
+}
+
+#[tauri::command]
+pub async fn get_cost_alerts(app: AppHandle) -> Result<Vec<crate::cost_tracking::CostAlert>, String> {
+    let mut history = load_cost_history(&app).await;
+    let alerts = history.check_alerts();
+
+    // Save updated alert state
+    save_cost_history(&app, &history).await?;
+
+    Ok(alerts)
+}
+
+#[tauri::command]
+pub async fn set_cost_alert_thresholds(
+    app: AppHandle,
+    daily: Option<f64>,
+    weekly: Option<f64>,
+    monthly: Option<f64>,
+) -> Result<(), String> {
+    let mut history = load_cost_history(&app).await;
+    history.set_alert_thresholds(daily, weekly, monthly);
+    save_cost_history(&app, &history).await
+}
+
+#[tauri::command]
+pub async fn export_cost_csv(app: AppHandle, days: u32) -> Result<String, String> {
+    let history = load_cost_history(&app).await;
+    Ok(history.export_csv(days))
+}
+
+#[tauri::command]
+pub async fn get_today_cost(app: AppHandle) -> Result<f64, String> {
+    let history = load_cost_history(&app).await;
+    Ok(history.get_today_cost())
+}
+
+#[tauri::command]
+pub async fn get_week_cost(app: AppHandle) -> Result<f64, String> {
+    let history = load_cost_history(&app).await;
+    Ok(history.get_week_cost())
+}
+
+#[tauri::command]
+pub async fn get_month_cost(app: AppHandle) -> Result<f64, String> {
+    let history = load_cost_history(&app).await;
+    Ok(history.get_month_cost())
+}
+
+/// Add cost to history (called internally when stats are updated)
+pub async fn record_cost(app: &AppHandle, input_tokens: u64, output_tokens: u64, cost_usd: f64) {
+    let mut history = load_cost_history(app).await;
+    history.add_cost(input_tokens, output_tokens, cost_usd);
+    let _ = save_cost_history(app, &history).await;
+}
+
+/// Record a new session
+pub async fn record_session(app: &AppHandle) {
+    let mut history = load_cost_history(app).await;
+    history.increment_sessions();
+    let _ = save_cost_history(app, &history).await;
+}
+
+async fn load_cost_history(app: &AppHandle) -> crate::cost_tracking::CostHistory {
+    let store = match app.store("hikari-cost-history.json") {
+        Ok(s) => s,
+        Err(_) => return crate::cost_tracking::CostHistory::new(),
+    };
+
+    match store.get(COST_HISTORY_STORE_KEY) {
+        Some(value) => serde_json::from_value(value.clone()).unwrap_or_default(),
+        None => crate::cost_tracking::CostHistory::new(),
+    }
+}
+
+async fn save_cost_history(app: &AppHandle, history: &crate::cost_tracking::CostHistory) -> Result<(), String> {
+    let store = app.store("hikari-cost-history.json").map_err(|e| e.to_string())?;
+    let value = serde_json::to_value(history).map_err(|e| e.to_string())?;
+    store.set(COST_HISTORY_STORE_KEY, value);
+    store.save().map_err(|e| e.to_string())?;
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src-tauri/src/config.rs

@@ -96,6 +96,22 @@ pub struct HikariConfig {
     // Custom theme colors
     #[serde(default)]
     pub custom_theme_colors: CustomThemeColors,
+
+    // Token budget settings
+    #[serde(default)]
+    pub budget_enabled: bool,
+
+    #[serde(default)]
+    pub session_token_budget: Option<u64>,
+
+    #[serde(default)]
+    pub session_cost_budget: Option<f64>,
+
+    #[serde(default = "default_budget_action")]
+    pub budget_action: BudgetAction,
+
+    #[serde(default = "default_budget_warning_threshold")]
+    pub budget_warning_threshold: f32,
 }
 
 impl Default for HikariConfig {
@@ -123,6 +139,11 @@ impl Default for HikariConfig {
             profile_avatar_path: None,
             profile_bio: None,
             custom_theme_colors: CustomThemeColors::default(),
+            budget_enabled: false,
+            session_token_budget: None,
+            session_cost_budget: None,
+            budget_action: BudgetAction::Warn,
+            budget_warning_threshold: 0.8,
         }
     }
 }
@@ -147,6 +168,22 @@ fn default_font_size() -> u32 {
     14
 }
 
+fn default_budget_action() -> BudgetAction {
+    BudgetAction::Warn
+}
+
+fn default_budget_warning_threshold() -> f32 {
+    0.8
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, Default, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum BudgetAction {
+    #[default]
+    Warn,
+    Block,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, Default, PartialEq)]
 #[serde(rename_all = "lowercase")]
 pub enum Theme {
@@ -205,6 +242,11 @@ mod tests {
         assert!(config.profile_avatar_path.is_none());
         assert!(config.profile_bio.is_none());
         assert_eq!(config.custom_theme_colors, CustomThemeColors::default());
+        assert!(!config.budget_enabled);
+        assert!(config.session_token_budget.is_none());
+        assert!(config.session_cost_budget.is_none());
+        assert_eq!(config.budget_action, BudgetAction::Warn);
+        assert!((config.budget_warning_threshold - 0.8).abs() < f32::EPSILON);
     }
 
     #[test]
@@ -232,6 +274,11 @@ mod tests {
             profile_avatar_path: None,
             profile_bio: Some("A test bio".to_string()),
             custom_theme_colors: CustomThemeColors::default(),
+            budget_enabled: true,
+            session_token_budget: Some(100000),
+            session_cost_budget: Some(1.50),
+            budget_action: BudgetAction::Block,
+            budget_warning_threshold: 0.75,
         };
 
         let json = serde_json::to_string(&config).unwrap();

src-tauri/src/cost_tracking.rs

@@ -0,0 +1,376 @@
+use chrono::{Datelike, Local, NaiveDate, Weekday};
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+/// Represents a single day's cost data
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct DailyCost {
+    pub date: String, // ISO date string (YYYY-MM-DD)
+    pub input_tokens: u64,
+    pub output_tokens: u64,
+    pub cost_usd: f64,
+    pub messages_sent: u64,
+    pub sessions_count: u64,
+}
+
+/// Historical cost tracking data
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct CostHistory {
+    /// Daily costs indexed by date string (YYYY-MM-DD)
+    pub daily_costs: HashMap<String, DailyCost>,
+    /// Cost alert thresholds
+    pub daily_alert_threshold: Option<f64>,
+    pub weekly_alert_threshold: Option<f64>,
+    pub monthly_alert_threshold: Option<f64>,
+    /// Whether alerts have been triggered today
+    pub daily_alert_triggered: bool,
+    pub weekly_alert_triggered: bool,
+    pub monthly_alert_triggered: bool,
+    pub last_alert_reset_date: Option<String>,
+}
+
+impl CostHistory {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Get today's date as a string
+    fn today_str() -> String {
+        Local::now().format("%Y-%m-%d").to_string()
+    }
+
+    /// Get the start of the current week (Monday)
+    fn week_start() -> NaiveDate {
+        let today = Local::now().date_naive();
+        let days_since_monday = today.weekday().num_days_from_monday();
+        today - chrono::Duration::days(days_since_monday as i64)
+    }
+
+    /// Get the start of the current month
+    fn month_start() -> NaiveDate {
+        let today = Local::now().date_naive();
+        NaiveDate::from_ymd_opt(today.year(), today.month(), 1).unwrap_or(today)
+    }
+
+    /// Add cost for today
+    pub fn add_cost(&mut self, input_tokens: u64, output_tokens: u64, cost_usd: f64) {
+        let today = Self::today_str();
+
+        // Reset alert flags if it's a new day
+        if self.last_alert_reset_date.as_ref() != Some(&today) {
+            self.daily_alert_triggered = false;
+            // Reset weekly on Monday
+            if Local::now().weekday() == Weekday::Mon {
+                self.weekly_alert_triggered = false;
+            }
+            // Reset monthly on the 1st
+            if Local::now().day() == 1 {
+                self.monthly_alert_triggered = false;
+            }
+            self.last_alert_reset_date = Some(today.clone());
+        }
+
+        let daily = self.daily_costs.entry(today).or_default();
+        daily.input_tokens += input_tokens;
+        daily.output_tokens += output_tokens;
+        daily.cost_usd += cost_usd;
+        daily.messages_sent += 1;
+    }
+
+    /// Increment session count for today
+    pub fn increment_sessions(&mut self) {
+        let today = Self::today_str();
+        let daily = self.daily_costs.entry(today.clone()).or_insert_with(|| DailyCost {
+            date: today,
+            ..Default::default()
+        });
+        daily.sessions_count += 1;
+    }
+
+    /// Get today's cost
+    pub fn get_today_cost(&self) -> f64 {
+        self.daily_costs
+            .get(&Self::today_str())
+            .map(|d| d.cost_usd)
+            .unwrap_or(0.0)
+    }
+
+    /// Get this week's cost (Monday to Sunday)
+    pub fn get_week_cost(&self) -> f64 {
+        let week_start = Self::week_start();
+        self.daily_costs
+            .values()
+            .filter(|d| {
+                NaiveDate::parse_from_str(&d.date, "%Y-%m-%d")
+                    .map(|date| date >= week_start)
+                    .unwrap_or(false)
+            })
+            .map(|d| d.cost_usd)
+            .sum()
+    }
+
+    /// Get this month's cost
+    pub fn get_month_cost(&self) -> f64 {
+        let month_start = Self::month_start();
+        self.daily_costs
+            .values()
+            .filter(|d| {
+                NaiveDate::parse_from_str(&d.date, "%Y-%m-%d")
+                    .map(|date| date >= month_start)
+                    .unwrap_or(false)
+            })
+            .map(|d| d.cost_usd)
+            .sum()
+    }
+
+    /// Get cost summary for a date range
+    pub fn get_summary(&self, days: u32) -> CostSummary {
+        let today = Local::now().date_naive();
+        let start_date = today - chrono::Duration::days(days as i64 - 1);
+
+        let mut total_input_tokens = 0u64;
+        let mut total_output_tokens = 0u64;
+        let mut total_cost = 0.0f64;
+        let mut total_messages = 0u64;
+        let mut total_sessions = 0u64;
+        let mut daily_breakdown = Vec::new();
+
+        for i in 0..days {
+            let date = start_date + chrono::Duration::days(i as i64);
+            let date_str = date.format("%Y-%m-%d").to_string();
+
+            if let Some(daily) = self.daily_costs.get(&date_str) {
+                total_input_tokens += daily.input_tokens;
+                total_output_tokens += daily.output_tokens;
+                total_cost += daily.cost_usd;
+                total_messages += daily.messages_sent;
+                total_sessions += daily.sessions_count;
+                daily_breakdown.push(daily.clone());
+            } else {
+                daily_breakdown.push(DailyCost {
+                    date: date_str,
+                    ..Default::default()
+                });
+            }
+        }
+
+        CostSummary {
+            period_days: days,
+            total_input_tokens,
+            total_output_tokens,
+            total_cost,
+            total_messages,
+            total_sessions,
+            average_daily_cost: if days > 0 { total_cost / days as f64 } else { 0.0 },
+            daily_breakdown,
+        }
+    }
+
+    /// Check if any alert thresholds are exceeded and return which ones
+    pub fn check_alerts(&mut self) -> Vec<CostAlert> {
+        let mut alerts = Vec::new();
+
+        if let Some(threshold) = self.daily_alert_threshold {
+            let today_cost = self.get_today_cost();
+            if today_cost >= threshold && !self.daily_alert_triggered {
+                self.daily_alert_triggered = true;
+                alerts.push(CostAlert {
+                    alert_type: AlertType::Daily,
+                    threshold,
+                    current_cost: today_cost,
+                });
+            }
+        }
+
+        if let Some(threshold) = self.weekly_alert_threshold {
+            let week_cost = self.get_week_cost();
+            if week_cost >= threshold && !self.weekly_alert_triggered {
+                self.weekly_alert_triggered = true;
+                alerts.push(CostAlert {
+                    alert_type: AlertType::Weekly,
+                    threshold,
+                    current_cost: week_cost,
+                });
+            }
+        }
+
+        if let Some(threshold) = self.monthly_alert_threshold {
+            let month_cost = self.get_month_cost();
+            if month_cost >= threshold && !self.monthly_alert_triggered {
+                self.monthly_alert_triggered = true;
+                alerts.push(CostAlert {
+                    alert_type: AlertType::Monthly,
+                    threshold,
+                    current_cost: month_cost,
+                });
+            }
+        }
+
+        alerts
+    }
+
+    /// Set alert thresholds
+    pub fn set_alert_thresholds(
+        &mut self,
+        daily: Option<f64>,
+        weekly: Option<f64>,
+        monthly: Option<f64>,
+    ) {
+        self.daily_alert_threshold = daily;
+        self.weekly_alert_threshold = weekly;
+        self.monthly_alert_threshold = monthly;
+    }
+
+    /// Clean up old data (keep last N days)
+    #[allow(dead_code)]
+    pub fn cleanup_old_data(&mut self, keep_days: u32) {
+        let cutoff = Local::now().date_naive() - chrono::Duration::days(keep_days as i64);
+        self.daily_costs.retain(|date_str, _| {
+            NaiveDate::parse_from_str(date_str, "%Y-%m-%d")
+                .map(|date| date >= cutoff)
+                .unwrap_or(false)
+        });
+    }
+
+    /// Export to CSV format
+    pub fn export_csv(&self, days: u32) -> String {
+        let summary = self.get_summary(days);
+        let mut csv = String::from("Date,Input Tokens,Output Tokens,Cost (USD),Messages,Sessions\n");
+
+        for daily in &summary.daily_breakdown {
+            csv.push_str(&format!(
+                "{},{},{},{:.4},{},{}\n",
+                daily.date,
+                daily.input_tokens,
+                daily.output_tokens,
+                daily.cost_usd,
+                daily.messages_sent,
+                daily.sessions_count
+            ));
+        }
+
+        // Add totals row
+        csv.push_str(&format!(
+            "TOTAL,{},{},{:.4},{},{}\n",
+            summary.total_input_tokens,
+            summary.total_output_tokens,
+            summary.total_cost,
+            summary.total_messages,
+            summary.total_sessions
+        ));
+
+        csv
+    }
+}
+
+/// Cost summary for a period
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct CostSummary {
+    pub period_days: u32,
+    pub total_input_tokens: u64,
+    pub total_output_tokens: u64,
+    pub total_cost: f64,
+    pub total_messages: u64,
+    pub total_sessions: u64,
+    pub average_daily_cost: f64,
+    pub daily_breakdown: Vec<DailyCost>,
+}
+
+/// Alert types
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub enum AlertType {
+    Daily,
+    Weekly,
+    Monthly,
+}
+
+/// Cost alert notification
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct CostAlert {
+    pub alert_type: AlertType,
+    pub threshold: f64,
+    pub current_cost: f64,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_add_cost() {
+        let mut history = CostHistory::new();
+        history.add_cost(1000, 500, 0.05);
+
+        let today_cost = history.get_today_cost();
+        assert!((today_cost - 0.05).abs() < 0.0001);
+    }
+
+    #[test]
+    fn test_accumulate_daily_cost() {
+        let mut history = CostHistory::new();
+        history.add_cost(1000, 500, 0.05);
+        history.add_cost(2000, 1000, 0.10);
+
+        let today_cost = history.get_today_cost();
+        assert!((today_cost - 0.15).abs() < 0.0001);
+    }
+
+    #[test]
+    fn test_summary() {
+        let mut history = CostHistory::new();
+        history.add_cost(1000, 500, 0.05);
+
+        let summary = history.get_summary(7);
+        assert_eq!(summary.period_days, 7);
+        assert!((summary.total_cost - 0.05).abs() < 0.0001);
+    }
+
+    #[test]
+    fn test_daily_alert() {
+        let mut history = CostHistory::new();
+        history.set_alert_thresholds(Some(0.10), None, None);
+
+        history.add_cost(1000, 500, 0.05);
+        let alerts = history.check_alerts();
+        assert!(alerts.is_empty());
+
+        history.add_cost(1000, 500, 0.06);
+        let alerts = history.check_alerts();
+        assert_eq!(alerts.len(), 1);
+        assert_eq!(alerts[0].alert_type, AlertType::Daily);
+    }
+
+    #[test]
+    fn test_alert_only_triggers_once() {
+        let mut history = CostHistory::new();
+        history.set_alert_thresholds(Some(0.10), None, None);
+
+        history.add_cost(1000, 500, 0.15);
+        let alerts = history.check_alerts();
+        assert_eq!(alerts.len(), 1);
+
+        // Second check should not trigger again
+        let alerts = history.check_alerts();
+        assert!(alerts.is_empty());
+    }
+
+    #[test]
+    fn test_export_csv() {
+        let mut history = CostHistory::new();
+        history.add_cost(1000, 500, 0.05);
+
+        let csv = history.export_csv(1);
+        assert!(csv.contains("Date,Input Tokens"));
+        assert!(csv.contains("TOTAL"));
+    }
+
+    #[test]
+    fn test_increment_sessions() {
+        let mut history = CostHistory::new();
+        history.increment_sessions();
+        history.increment_sessions();
+
+        let summary = history.get_summary(1);
+        assert_eq!(summary.total_sessions, 2);
+    }
+}

src-tauri/src/lib.rs

@@ -3,6 +3,7 @@ mod bridge_manager;
 mod clipboard;
 mod commands;
 mod config;
+mod cost_tracking;
 mod git;
 mod notifications;
 mod quick_actions;
@@ -10,6 +11,7 @@ mod sessions;
 mod snippets;
 mod stats;
 mod temp_manager;
+mod tool_cache;
 mod tray;
 mod types;
 mod vbs_notification;
@@ -151,6 +153,22 @@ pub fn run() {
             search_clipboard_entries,
             get_clipboard_languages,
             update_clipboard_language,
+            list_directory,
+            read_file_content,
+            write_file_content,
+            create_file,
+            create_directory,
+            delete_file,
+            delete_directory,
+            rename_path,
+            // Cost tracking commands
+            get_cost_summary,
+            get_cost_alerts,
+            set_cost_alert_thresholds,
+            export_cost_csv,
+            get_today_cost,
+            get_week_cost,
+            get_month_cost,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");

src-tauri/src/stats.rs

@@ -5,6 +5,110 @@ use std::collections::HashMap;
 use std::time::Instant;
 use tauri_plugin_store::StoreExt;
 
+/// Per-tool token usage statistics
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct ToolTokenStats {
+    pub call_count: u64,
+    pub estimated_input_tokens: u64,
+    pub estimated_output_tokens: u64,
+}
+
+impl ToolTokenStats {
+    #[allow(dead_code)]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn increment_call(&mut self) {
+        self.call_count += 1;
+    }
+
+    pub fn add_tokens(&mut self, input: u64, output: u64) {
+        self.estimated_input_tokens += input;
+        self.estimated_output_tokens += output;
+    }
+
+    #[allow(dead_code)]
+    pub fn total_tokens(&self) -> u64 {
+        self.estimated_input_tokens + self.estimated_output_tokens
+    }
+}
+
+/// Warning levels for context window utilisation
+#[allow(dead_code)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum ContextWarning {
+    /// 50-74% utilisation - conversation is getting long
+    Moderate,
+    /// 75-89% utilisation - consider summarising
+    High,
+    /// 90%+ utilisation - approaching limit
+    Critical,
+}
+
+/// Budget status indicating whether user is within their limits
+#[allow(dead_code)]
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
+pub enum BudgetStatus {
+    /// Within budget, no concerns
+    Ok,
+    /// Approaching budget limit (warning threshold reached)
+    Warning {
+        budget_type: BudgetType,
+        percent_used: f32,
+    },
+    /// Budget exceeded
+    Exceeded { budget_type: BudgetType },
+}
+
+/// Type of budget limit
+#[allow(dead_code)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum BudgetType {
+    Token,
+    Cost,
+}
+
+impl ContextWarning {
+    #[allow(dead_code)]
+    pub fn message(&self) -> &'static str {
+        match self {
+            ContextWarning::Moderate => "Context window is 50%+ full. Consider starting a new conversation for better performance.",
+            ContextWarning::High => "Context window is 75%+ full. Responses may degrade. Consider summarising or starting fresh.",
+            ContextWarning::Critical => "Context window is nearly full (90%+)! Start a new conversation to avoid errors.",
+        }
+    }
+}
+
+/// Get the context window limit (in tokens) for a given model
+fn get_context_window_limit(model: &str) -> u64 {
+    match model {
+        // Claude 4.5 family - 200K standard context
+        "claude-opus-4-5-20251101"
+        | "claude-sonnet-4-5-20250929"
+        | "claude-haiku-4-5-20251001" => 200_000,
+        // Claude 4.x family - 200K standard context
+        "claude-opus-4-1-20250805"
+        | "claude-opus-4-20250514"
+        | "claude-sonnet-4-20250514" => 200_000,
+        // Claude 3.x family
+        "claude-3-7-sonnet-20250219"
+        | "claude-3-5-sonnet-20241022"
+        | "claude-3-5-sonnet-20240620"
+        | "claude-3-5-haiku-20241022"
+        | "claude-3-opus-20240229"
+        | "claude-3-sonnet-20240229"
+        | "claude-3-haiku-20240307" => 200_000,
+        // Default to 200K for unknown Claude models
+        _ if model.starts_with("claude") => 200_000,
+        // For non-Claude models (Ollama, etc.), use a conservative default
+        _ => 128_000,
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
 pub struct UsageStats {
     pub total_input_tokens: u64,
@@ -24,8 +128,8 @@ pub struct UsageStats {
     pub session_files_edited: u64,
     pub files_created: u64,
     pub session_files_created: u64,
-    pub tools_usage: HashMap<String, u64>,
+    pub tools_usage: HashMap<String, ToolTokenStats>,
-    pub session_tools_usage: HashMap<String, u64>,
+    pub session_tools_usage: HashMap<String, ToolTokenStats>,
     pub session_duration_seconds: u64,
     #[serde(skip)]
     pub session_start: Option<Instant>,
@@ -38,6 +142,15 @@ pub struct UsageStats {
     pub night_sessions: u64,   // Sessions started after 10 PM
     pub last_session_date: Option<String>, // ISO date string for streak tracking
 
+    // Context window tracking
+    pub context_tokens_used: u64,
+    pub context_window_limit: u64,
+    pub context_utilisation_percent: f32,
+
+    // Cache analytics (tracks potential savings from repeated tool calls)
+    pub potential_cache_hits: u64,
+    pub potential_cache_savings_tokens: u64,
+
     // Achievement tracking
     #[serde(skip)]
     pub achievements: AchievementProgress,
@@ -61,6 +174,114 @@ impl UsageStats {
         self.session_cost_usd += cost;
 
         self.model = Some(model.to_string());
+
+        // Update context window tracking
+        self.update_context_tracking(model);
+    }
+
+    pub fn update_context_tracking(&mut self, model: &str) {
+        // Get context window limit for the current model
+        self.context_window_limit = get_context_window_limit(model);
+
+        // Context tokens = input tokens (the prompt/context sent to the model)
+        // We track cumulative session input as a proxy for context growth
+        self.context_tokens_used = self.session_input_tokens;
+
+        // Calculate utilisation percentage
+        if self.context_window_limit > 0 {
+            self.context_utilisation_percent =
+                (self.context_tokens_used as f32 / self.context_window_limit as f32) * 100.0;
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn get_context_warning(&self) -> Option<ContextWarning> {
+        if self.context_utilisation_percent >= 90.0 {
+            Some(ContextWarning::Critical)
+        } else if self.context_utilisation_percent >= 75.0 {
+            Some(ContextWarning::High)
+        } else if self.context_utilisation_percent >= 50.0 {
+            Some(ContextWarning::Moderate)
+        } else {
+            None
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn estimate_remaining_tokens(&self) -> u64 {
+        self.context_window_limit
+            .saturating_sub(self.context_tokens_used)
+    }
+
+    /// Check budget status given current usage and budget settings
+    #[allow(dead_code)]
+    pub fn check_budget(
+        &self,
+        budget_enabled: bool,
+        token_budget: Option<u64>,
+        cost_budget: Option<f64>,
+        warning_threshold: f32,
+    ) -> BudgetStatus {
+        if !budget_enabled {
+            return BudgetStatus::Ok;
+        }
+
+        let session_tokens = self.session_input_tokens + self.session_output_tokens;
+
+        // Check token budget
+        if let Some(limit) = token_budget {
+            if session_tokens >= limit {
+                return BudgetStatus::Exceeded {
+                    budget_type: BudgetType::Token,
+                };
+            }
+            let percent_used = session_tokens as f32 / limit as f32;
+            if percent_used >= warning_threshold {
+                return BudgetStatus::Warning {
+                    budget_type: BudgetType::Token,
+                    percent_used: percent_used * 100.0,
+                };
+            }
+        }
+
+        // Check cost budget
+        if let Some(limit) = cost_budget {
+            if self.session_cost_usd >= limit {
+                return BudgetStatus::Exceeded {
+                    budget_type: BudgetType::Cost,
+                };
+            }
+            let percent_used = (self.session_cost_usd / limit) as f32;
+            if percent_used >= warning_threshold {
+                return BudgetStatus::Warning {
+                    budget_type: BudgetType::Cost,
+                    percent_used: percent_used * 100.0,
+                };
+            }
+        }
+
+        BudgetStatus::Ok
+    }
+
+    /// Get remaining token budget (None if no budget set)
+    #[allow(dead_code)]
+    pub fn get_remaining_token_budget(&self, token_budget: Option<u64>) -> Option<u64> {
+        token_budget.map(|limit| {
+            let used = self.session_input_tokens + self.session_output_tokens;
+            limit.saturating_sub(used)
+        })
+    }
+
+    /// Get remaining cost budget (None if no budget set)
+    #[allow(dead_code)]
+    pub fn get_remaining_cost_budget(&self, cost_budget: Option<f64>) -> Option<f64> {
+        cost_budget.map(|limit| {
+            if limit > self.session_cost_usd {
+                limit - self.session_cost_usd
+            } else {
+                0.0
+            }
+        })
     }
 
     pub fn reset_session(&mut self) {
@@ -76,6 +297,13 @@ impl UsageStats {
         self.session_start = Some(Instant::now());
         self.achievements.start_session();
 
+        // Reset context window tracking
+        self.context_tokens_used = 0;
+        self.context_utilisation_percent = 0.0;
+
+        // Note: Cache analytics are NOT reset here - they're cumulative across sessions
+        // to show total potential savings over time
+
         // Track session start for achievements
         self.track_session_start();
     }
@@ -139,11 +367,32 @@ impl UsageStats {
     }
 
     pub fn increment_tool_usage(&mut self, tool_name: &str) {
-        *self.tools_usage.entry(tool_name.to_string()).or_insert(0) += 1;
+        self.tools_usage
-        *self
-            .session_tools_usage
             .entry(tool_name.to_string())
-            .or_insert(0) += 1;
+            .or_default()
+            .increment_call();
+        self.session_tools_usage
+            .entry(tool_name.to_string())
+            .or_default()
+            .increment_call();
+    }
+
+    pub fn add_tool_tokens(&mut self, tool_name: &str, input_tokens: u64, output_tokens: u64) {
+        self.tools_usage
+            .entry(tool_name.to_string())
+            .or_default()
+            .add_tokens(input_tokens, output_tokens);
+        self.session_tools_usage
+            .entry(tool_name.to_string())
+            .or_default()
+            .add_tokens(input_tokens, output_tokens);
+    }
+
+    /// Record a potential cache hit (when the same tool call is made twice)
+    #[allow(dead_code)]
+    pub fn add_potential_cache_hit(&mut self, tokens_saved: u64) {
+        self.potential_cache_hits += 1;
+        self.potential_cache_savings_tokens += tokens_saved;
     }
 
     pub fn get_session_duration(&mut self) -> u64 {
@@ -184,6 +433,11 @@ impl UsageStats {
             morning_sessions: self.morning_sessions,
             night_sessions: self.night_sessions,
             last_session_date: self.last_session_date.clone(),
+            context_tokens_used: self.context_tokens_used,
+            context_window_limit: self.context_window_limit,
+            context_utilisation_percent: self.context_utilisation_percent,
+            potential_cache_hits: self.potential_cache_hits,
+            potential_cache_savings_tokens: self.potential_cache_savings_tokens,
             achievements: AchievementProgress::new(), // Dummy for copy
         };
         check_achievements(&stats_copy, &mut self.achievements)
@@ -206,20 +460,22 @@ fn is_consecutive_day(prev_date: &str, current_date: &str) -> bool {
     }
 }
 
-// Pricing as of January 2025
+// Pricing as of February 2026
-// https://www.anthropic.com/pricing
+// https://platform.claude.com/docs/en/about-claude/models/overview
-fn calculate_cost(input_tokens: u64, output_tokens: u64, model: &str) -> f64 {
+pub fn calculate_cost(input_tokens: u64, output_tokens: u64, model: &str) -> f64 {
     let (input_price_per_million, output_price_per_million) = match model {
-        // Opus 4.5
+        // Current generation (Claude 4.5)
-        "claude-opus-4-5-20251101" => (15.0, 75.0),
+        "claude-opus-4-5-20251101" => (5.0, 25.0),
+        "claude-sonnet-4-5-20250929" => (3.0, 15.0),
+        "claude-haiku-4-5-20251001" => (1.0, 5.0),
 
-        // Opus 4
+        // Previous generation (Claude 4.x)
+        "claude-opus-4-1-20250805" => (15.0, 75.0),
         "claude-opus-4-20250514" => (15.0, 75.0),
-
-        // Sonnet 4
         "claude-sonnet-4-20250514" => (3.0, 15.0),
 
-        // Previous generation models
+        // Legacy (Claude 3.x)
+        "claude-3-7-sonnet-20250219" => (3.0, 15.0),
         "claude-3-5-sonnet-20241022" => (3.0, 15.0),
         "claude-3-5-sonnet-20240620" => (3.0, 15.0),
         "claude-3-5-haiku-20241022" => (1.0, 5.0),
@@ -252,7 +508,7 @@ pub struct PersistedStats {
     pub code_blocks_generated: u64,
     pub files_edited: u64,
     pub files_created: u64,
-    pub tools_usage: HashMap<String, u64>,
+    pub tools_usage: HashMap<String, ToolTokenStats>,
     pub sessions_started: u64,
     pub consecutive_days: u64,
     pub total_days_used: u64,
@@ -372,8 +628,10 @@ mod tests {
     #[test]
     fn test_cost_calculation_opus_45() {
         let cost = calculate_cost(1000, 2000, "claude-opus-4-5-20251101");
-        // Same pricing as Opus 4
+        // Opus 4.5 pricing: $5/MTok input, $25/MTok output
-        assert!((cost - 0.165).abs() < 0.0001);
+        // 1000 input tokens = $0.005, 2000 output tokens = $0.05
+        // Total = $0.055
+        assert!((cost - 0.055).abs() < 0.0001);
     }
 
     #[test]
@@ -512,10 +770,33 @@ mod tests {
         stats.increment_tool_usage("Read");
         stats.increment_tool_usage("Write");
 
-        assert_eq!(stats.tools_usage.get("Read"), Some(&2));
+        assert_eq!(stats.tools_usage.get("Read").map(|t| t.call_count), Some(2));
-        assert_eq!(stats.tools_usage.get("Write"), Some(&1));
+        assert_eq!(stats.tools_usage.get("Write").map(|t| t.call_count), Some(1));
-        assert_eq!(stats.session_tools_usage.get("Read"), Some(&2));
+        assert_eq!(stats.session_tools_usage.get("Read").map(|t| t.call_count), Some(2));
-        assert_eq!(stats.session_tools_usage.get("Write"), Some(&1));
+        assert_eq!(stats.session_tools_usage.get("Write").map(|t| t.call_count), Some(1));
+    }
+
+    #[test]
+    fn test_add_tool_tokens() {
+        let mut stats = UsageStats::new();
+        stats.increment_tool_usage("Read");
+        stats.add_tool_tokens("Read", 100, 50);
+        stats.add_tool_tokens("Read", 200, 100);
+
+        let read_stats = stats.tools_usage.get("Read").unwrap();
+        assert_eq!(read_stats.call_count, 1);
+        assert_eq!(read_stats.estimated_input_tokens, 300);
+        assert_eq!(read_stats.estimated_output_tokens, 150);
+        assert_eq!(read_stats.total_tokens(), 450);
+    }
+
+    #[test]
+    fn test_tool_token_stats_default() {
+        let tool_stats = ToolTokenStats::new();
+        assert_eq!(tool_stats.call_count, 0);
+        assert_eq!(tool_stats.estimated_input_tokens, 0);
+        assert_eq!(tool_stats.estimated_output_tokens, 0);
+        assert_eq!(tool_stats.total_tokens(), 0);
     }
 
     #[test]
@@ -590,7 +871,11 @@ mod tests {
             files_created: 5,
             tools_usage: {
                 let mut map = HashMap::new();
-                map.insert("Read".to_string(), 50);
+                map.insert("Read".to_string(), ToolTokenStats {
+                    call_count: 50,
+                    estimated_input_tokens: 5000,
+                    estimated_output_tokens: 2500,
+                });
                 map
             },
             sessions_started: 10,
@@ -608,7 +893,8 @@ mod tests {
         assert_eq!(stats.total_output_tokens, 20000);
         assert_eq!(stats.total_cost_usd, 5.50);
         assert_eq!(stats.messages_exchanged, 100);
-        assert_eq!(stats.tools_usage.get("Read"), Some(&50));
+        assert_eq!(stats.tools_usage.get("Read").map(|t| t.call_count), Some(50));
+        assert_eq!(stats.tools_usage.get("Read").map(|t| t.estimated_input_tokens), Some(5000));
         assert_eq!(stats.consecutive_days, 7);
         assert_eq!(stats.morning_sessions, 3);
         assert_eq!(stats.last_session_date, Some("2024-06-15".to_string()));
@@ -672,4 +958,351 @@ mod tests {
         assert!(json.contains("stats"));
         assert!(json.contains("total_input_tokens"));
     }
+
+    // =====================
+    // Context Window Tracking tests
+    // =====================
+
+    #[test]
+    fn test_context_window_limit_claude_4() {
+        assert_eq!(get_context_window_limit("claude-opus-4-5-20251101"), 200_000);
+        assert_eq!(get_context_window_limit("claude-opus-4-20250514"), 200_000);
+        assert_eq!(get_context_window_limit("claude-sonnet-4-20250514"), 200_000);
+    }
+
+    #[test]
+    fn test_context_window_limit_claude_35() {
+        assert_eq!(
+            get_context_window_limit("claude-3-5-sonnet-20241022"),
+            200_000
+        );
+        assert_eq!(
+            get_context_window_limit("claude-3-5-sonnet-20240620"),
+            200_000
+        );
+        assert_eq!(
+            get_context_window_limit("claude-3-5-haiku-20241022"),
+            200_000
+        );
+    }
+
+    #[test]
+    fn test_context_window_limit_unknown_claude() {
+        assert_eq!(
+            get_context_window_limit("claude-some-future-model"),
+            200_000
+        );
+    }
+
+    #[test]
+    fn test_context_window_limit_non_claude() {
+        assert_eq!(get_context_window_limit("gpt-4"), 128_000);
+        assert_eq!(get_context_window_limit("llama-3"), 128_000);
+        assert_eq!(get_context_window_limit("unknown-model"), 128_000);
+    }
+
+    #[test]
+    fn test_context_tracking_update() {
+        let mut stats = UsageStats::new();
+        stats.add_usage(50_000, 10_000, "claude-sonnet-4-20250514");
+
+        assert_eq!(stats.context_tokens_used, 50_000);
+        assert_eq!(stats.context_window_limit, 200_000);
+        assert!((stats.context_utilisation_percent - 25.0).abs() < 0.1);
+    }
+
+    #[test]
+    fn test_context_tracking_accumulates() {
+        let mut stats = UsageStats::new();
+        stats.add_usage(50_000, 10_000, "claude-sonnet-4-20250514");
+        stats.add_usage(50_000, 10_000, "claude-sonnet-4-20250514");
+
+        assert_eq!(stats.context_tokens_used, 100_000);
+        assert!((stats.context_utilisation_percent - 50.0).abs() < 0.1);
+    }
+
+    #[test]
+    fn test_context_warning_none() {
+        let mut stats = UsageStats::new();
+        stats.context_utilisation_percent = 40.0;
+        assert!(stats.get_context_warning().is_none());
+    }
+
+    #[test]
+    fn test_context_warning_moderate() {
+        let mut stats = UsageStats::new();
+        stats.context_utilisation_percent = 55.0;
+        assert_eq!(stats.get_context_warning(), Some(ContextWarning::Moderate));
+    }
+
+    #[test]
+    fn test_context_warning_high() {
+        let mut stats = UsageStats::new();
+        stats.context_utilisation_percent = 80.0;
+        assert_eq!(stats.get_context_warning(), Some(ContextWarning::High));
+    }
+
+    #[test]
+    fn test_context_warning_critical() {
+        let mut stats = UsageStats::new();
+        stats.context_utilisation_percent = 95.0;
+        assert_eq!(stats.get_context_warning(), Some(ContextWarning::Critical));
+    }
+
+    #[test]
+    fn test_estimate_remaining_tokens() {
+        let mut stats = UsageStats::new();
+        stats.context_tokens_used = 50_000;
+        stats.context_window_limit = 200_000;
+
+        assert_eq!(stats.estimate_remaining_tokens(), 150_000);
+    }
+
+    #[test]
+    fn test_estimate_remaining_tokens_at_limit() {
+        let mut stats = UsageStats::new();
+        stats.context_tokens_used = 200_000;
+        stats.context_window_limit = 200_000;
+
+        assert_eq!(stats.estimate_remaining_tokens(), 0);
+    }
+
+    #[test]
+    fn test_estimate_remaining_tokens_over_limit() {
+        let mut stats = UsageStats::new();
+        stats.context_tokens_used = 250_000;
+        stats.context_window_limit = 200_000;
+
+        assert_eq!(stats.estimate_remaining_tokens(), 0);
+    }
+
+    #[test]
+    fn test_context_reset_on_session_reset() {
+        let mut stats = UsageStats::new();
+        stats.add_usage(100_000, 20_000, "claude-sonnet-4-20250514");
+
+        assert!(stats.context_tokens_used > 0);
+        assert!(stats.context_utilisation_percent > 0.0);
+
+        stats.reset_session();
+
+        assert_eq!(stats.context_tokens_used, 0);
+        assert_eq!(stats.context_utilisation_percent, 0.0);
+    }
+
+    #[test]
+    fn test_context_warning_message() {
+        assert_eq!(
+            ContextWarning::Moderate.message(),
+            "Context window is 50%+ full. Consider starting a new conversation for better performance."
+        );
+        assert_eq!(
+            ContextWarning::High.message(),
+            "Context window is 75%+ full. Responses may degrade. Consider summarising or starting fresh."
+        );
+        assert_eq!(
+            ContextWarning::Critical.message(),
+            "Context window is nearly full (90%+)! Start a new conversation to avoid errors."
+        );
+    }
+
+    #[test]
+    fn test_context_warning_serialization() {
+        let warning = ContextWarning::Critical;
+        let json = serde_json::to_string(&warning).expect("Failed to serialize");
+        assert_eq!(json, "\"critical\"");
+
+        let warning = ContextWarning::Moderate;
+        let json = serde_json::to_string(&warning).expect("Failed to serialize");
+        assert_eq!(json, "\"moderate\"");
+    }
+
+    // =====================
+    // Budget Tracking tests
+    // =====================
+
+    #[test]
+    fn test_budget_disabled_returns_ok() {
+        let stats = UsageStats::new();
+        let status = stats.check_budget(false, Some(1000), Some(1.0), 0.8);
+        assert_eq!(status, BudgetStatus::Ok);
+    }
+
+    #[test]
+    fn test_budget_no_limits_returns_ok() {
+        let stats = UsageStats::new();
+        let status = stats.check_budget(true, None, None, 0.8);
+        assert_eq!(status, BudgetStatus::Ok);
+    }
+
+    #[test]
+    fn test_token_budget_within_limit() {
+        let mut stats = UsageStats::new();
+        stats.session_input_tokens = 500;
+        stats.session_output_tokens = 300;
+
+        let status = stats.check_budget(true, Some(10000), None, 0.8);
+        assert_eq!(status, BudgetStatus::Ok);
+    }
+
+    #[test]
+    fn test_token_budget_warning() {
+        let mut stats = UsageStats::new();
+        stats.session_input_tokens = 4500;
+        stats.session_output_tokens = 4000;
+
+        let status = stats.check_budget(true, Some(10000), None, 0.8);
+        match status {
+            BudgetStatus::Warning {
+                budget_type,
+                percent_used,
+            } => {
+                assert_eq!(budget_type, BudgetType::Token);
+                assert!(percent_used >= 80.0);
+            }
+            _ => panic!("Expected Warning status"),
+        }
+    }
+
+    #[test]
+    fn test_token_budget_exceeded() {
+        let mut stats = UsageStats::new();
+        stats.session_input_tokens = 6000;
+        stats.session_output_tokens = 5000;
+
+        let status = stats.check_budget(true, Some(10000), None, 0.8);
+        assert_eq!(
+            status,
+            BudgetStatus::Exceeded {
+                budget_type: BudgetType::Token
+            }
+        );
+    }
+
+    #[test]
+    fn test_cost_budget_within_limit() {
+        let mut stats = UsageStats::new();
+        stats.session_cost_usd = 0.50;
+
+        let status = stats.check_budget(true, None, Some(5.0), 0.8);
+        assert_eq!(status, BudgetStatus::Ok);
+    }
+
+    #[test]
+    fn test_cost_budget_warning() {
+        let mut stats = UsageStats::new();
+        stats.session_cost_usd = 4.25;
+
+        let status = stats.check_budget(true, None, Some(5.0), 0.8);
+        match status {
+            BudgetStatus::Warning {
+                budget_type,
+                percent_used,
+            } => {
+                assert_eq!(budget_type, BudgetType::Cost);
+                assert!(percent_used >= 80.0);
+            }
+            _ => panic!("Expected Warning status"),
+        }
+    }
+
+    #[test]
+    fn test_cost_budget_exceeded() {
+        let mut stats = UsageStats::new();
+        stats.session_cost_usd = 5.50;
+
+        let status = stats.check_budget(true, None, Some(5.0), 0.8);
+        assert_eq!(
+            status,
+            BudgetStatus::Exceeded {
+                budget_type: BudgetType::Cost
+            }
+        );
+    }
+
+    #[test]
+    fn test_token_budget_takes_priority() {
+        let mut stats = UsageStats::new();
+        stats.session_input_tokens = 12000;
+        stats.session_output_tokens = 0;
+        stats.session_cost_usd = 0.01;
+
+        // Token budget exceeded, cost budget OK
+        let status = stats.check_budget(true, Some(10000), Some(5.0), 0.8);
+        assert_eq!(
+            status,
+            BudgetStatus::Exceeded {
+                budget_type: BudgetType::Token
+            }
+        );
+    }
+
+    #[test]
+    fn test_remaining_token_budget() {
+        let mut stats = UsageStats::new();
+        stats.session_input_tokens = 3000;
+        stats.session_output_tokens = 2000;
+
+        assert_eq!(stats.get_remaining_token_budget(Some(10000)), Some(5000));
+        assert_eq!(stats.get_remaining_token_budget(None), None);
+    }
+
+    #[test]
+    fn test_remaining_token_budget_exceeded() {
+        let mut stats = UsageStats::new();
+        stats.session_input_tokens = 8000;
+        stats.session_output_tokens = 5000;
+
+        assert_eq!(stats.get_remaining_token_budget(Some(10000)), Some(0));
+    }
+
+    #[test]
+    fn test_remaining_cost_budget() {
+        let mut stats = UsageStats::new();
+        stats.session_cost_usd = 2.50;
+
+        let remaining = stats.get_remaining_cost_budget(Some(5.0));
+        assert!(remaining.is_some());
+        assert!((remaining.unwrap() - 2.50).abs() < 0.001);
+        assert_eq!(stats.get_remaining_cost_budget(None), None);
+    }
+
+    #[test]
+    fn test_remaining_cost_budget_exceeded() {
+        let mut stats = UsageStats::new();
+        stats.session_cost_usd = 6.0;
+
+        let remaining = stats.get_remaining_cost_budget(Some(5.0));
+        assert!(remaining.is_some());
+        assert!((remaining.unwrap() - 0.0).abs() < 0.001);
+    }
+
+    #[test]
+    fn test_budget_status_serialization() {
+        let status = BudgetStatus::Warning {
+            budget_type: BudgetType::Token,
+            percent_used: 85.5,
+        };
+        let json = serde_json::to_string(&status).expect("Failed to serialize");
+        assert!(json.contains("warning"));
+        assert!(json.contains("token"));
+
+        let status = BudgetStatus::Exceeded {
+            budget_type: BudgetType::Cost,
+        };
+        let json = serde_json::to_string(&status).expect("Failed to serialize");
+        assert!(json.contains("exceeded"));
+        assert!(json.contains("cost"));
+    }
+
+    #[test]
+    fn test_budget_type_serialization() {
+        let token = BudgetType::Token;
+        let json = serde_json::to_string(&token).expect("Failed to serialize");
+        assert_eq!(json, "\"token\"");
+
+        let cost = BudgetType::Cost;
+        let json = serde_json::to_string(&cost).expect("Failed to serialize");
+        assert_eq!(json, "\"cost\"");
+    }
 }

src-tauri/src/tool_cache.rs

@@ -0,0 +1,266 @@
+use serde::{Deserialize, Serialize};
+use std::collections::hash_map::DefaultHasher;
+use std::collections::HashMap;
+use std::hash::{Hash, Hasher};
+
+/// Tools that could benefit from caching
+#[allow(dead_code)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CacheableTool {
+    Read,
+    Glob,
+    Grep,
+}
+
+impl CacheableTool {
+    #[allow(dead_code)]
+    pub fn from_name(name: &str) -> Option<Self> {
+        match name {
+            "Read" => Some(Self::Read),
+            "Glob" => Some(Self::Glob),
+            "Grep" => Some(Self::Grep),
+            _ => None,
+        }
+    }
+}
+
+/// Statistics about potential cache savings
+#[allow(dead_code)]
+#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+pub struct CacheAnalytics {
+    /// Number of tool calls that could have been cache hits
+    pub potential_cache_hits: u64,
+    /// Estimated tokens that could have been saved
+    pub potential_savings_tokens: u64,
+    /// Tracks unique tool invocations: hash -> (tool_name, call_count)
+    #[serde(skip)]
+    recent_invocations: HashMap<u64, (String, u64)>,
+}
+
+#[allow(dead_code)]
+impl CacheAnalytics {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Compute a hash key from tool name and input
+    fn compute_key(tool_name: &str, input: &serde_json::Value) -> u64 {
+        let mut hasher = DefaultHasher::new();
+        tool_name.hash(&mut hasher);
+        input.to_string().hash(&mut hasher);
+        hasher.finish()
+    }
+
+    /// Track a tool invocation for analytics
+    /// Returns true if this was a repeated invocation (potential cache hit)
+    pub fn track_invocation(
+        &mut self,
+        tool_name: &str,
+        input: &serde_json::Value,
+        estimated_tokens: u64,
+    ) -> bool {
+        // Only track cacheable tools
+        if CacheableTool::from_name(tool_name).is_none() {
+            return false;
+        }
+
+        let key = Self::compute_key(tool_name, input);
+
+        if let Some((_, count)) = self.recent_invocations.get_mut(&key) {
+            *count += 1;
+            // This is a repeat - could have been a cache hit
+            self.potential_cache_hits += 1;
+            self.potential_savings_tokens += estimated_tokens;
+            true
+        } else {
+            self.recent_invocations
+                .insert(key, (tool_name.to_string(), 1));
+            false
+        }
+    }
+
+    /// Get the number of unique tool invocations being tracked
+    pub fn unique_invocations(&self) -> usize {
+        self.recent_invocations.len()
+    }
+
+    /// Get invocations that were called more than once
+    pub fn repeated_invocations(&self) -> Vec<(&str, u64)> {
+        self.recent_invocations
+            .values()
+            .filter(|(_, count)| *count > 1)
+            .map(|(name, count)| (name.as_str(), *count))
+            .collect()
+    }
+
+    /// Clear session analytics (keep totals)
+    pub fn clear_session(&mut self) {
+        self.recent_invocations.clear();
+    }
+
+    /// Fully reset all analytics
+    pub fn reset(&mut self) {
+        self.potential_cache_hits = 0;
+        self.potential_savings_tokens = 0;
+        self.recent_invocations.clear();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    #[test]
+    fn test_cacheable_tool_from_name() {
+        assert_eq!(CacheableTool::from_name("Read"), Some(CacheableTool::Read));
+        assert_eq!(CacheableTool::from_name("Glob"), Some(CacheableTool::Glob));
+        assert_eq!(CacheableTool::from_name("Grep"), Some(CacheableTool::Grep));
+        assert_eq!(CacheableTool::from_name("Bash"), None);
+        assert_eq!(CacheableTool::from_name("Edit"), None);
+        assert_eq!(CacheableTool::from_name("Write"), None);
+    }
+
+    #[test]
+    fn test_first_invocation_not_cache_hit() {
+        let mut analytics = CacheAnalytics::new();
+        let input = json!({"file_path": "/home/test/file.txt"});
+
+        let is_repeat = analytics.track_invocation("Read", &input, 100);
+
+        assert!(!is_repeat);
+        assert_eq!(analytics.potential_cache_hits, 0);
+        assert_eq!(analytics.potential_savings_tokens, 0);
+    }
+
+    #[test]
+    fn test_second_invocation_is_cache_hit() {
+        let mut analytics = CacheAnalytics::new();
+        let input = json!({"file_path": "/home/test/file.txt"});
+
+        analytics.track_invocation("Read", &input, 100);
+        let is_repeat = analytics.track_invocation("Read", &input, 100);
+
+        assert!(is_repeat);
+        assert_eq!(analytics.potential_cache_hits, 1);
+        assert_eq!(analytics.potential_savings_tokens, 100);
+    }
+
+    #[test]
+    fn test_different_inputs_not_cache_hit() {
+        let mut analytics = CacheAnalytics::new();
+        let input1 = json!({"file_path": "/home/test/file1.txt"});
+        let input2 = json!({"file_path": "/home/test/file2.txt"});
+
+        analytics.track_invocation("Read", &input1, 100);
+        let is_repeat = analytics.track_invocation("Read", &input2, 100);
+
+        assert!(!is_repeat);
+        assert_eq!(analytics.potential_cache_hits, 0);
+    }
+
+    #[test]
+    fn test_non_cacheable_tool_ignored() {
+        let mut analytics = CacheAnalytics::new();
+        let input = json!({"command": "ls -la"});
+
+        let is_repeat = analytics.track_invocation("Bash", &input, 100);
+        analytics.track_invocation("Bash", &input, 100);
+
+        assert!(!is_repeat);
+        assert_eq!(analytics.potential_cache_hits, 0);
+        assert_eq!(analytics.unique_invocations(), 0);
+    }
+
+    #[test]
+    fn test_multiple_repeated_invocations() {
+        let mut analytics = CacheAnalytics::new();
+        let input = json!({"file_path": "/home/test/file.txt"});
+
+        analytics.track_invocation("Read", &input, 100);
+        analytics.track_invocation("Read", &input, 100);
+        analytics.track_invocation("Read", &input, 100);
+
+        assert_eq!(analytics.potential_cache_hits, 2);
+        assert_eq!(analytics.potential_savings_tokens, 200);
+    }
+
+    #[test]
+    fn test_unique_invocations_count() {
+        let mut analytics = CacheAnalytics::new();
+
+        analytics.track_invocation("Read", &json!({"file_path": "/file1.txt"}), 100);
+        analytics.track_invocation("Read", &json!({"file_path": "/file2.txt"}), 100);
+        analytics.track_invocation("Glob", &json!({"pattern": "*.rs"}), 50);
+
+        assert_eq!(analytics.unique_invocations(), 3);
+    }
+
+    #[test]
+    fn test_repeated_invocations_list() {
+        let mut analytics = CacheAnalytics::new();
+
+        // file1 read twice
+        analytics.track_invocation("Read", &json!({"file_path": "/file1.txt"}), 100);
+        analytics.track_invocation("Read", &json!({"file_path": "/file1.txt"}), 100);
+
+        // file2 read once
+        analytics.track_invocation("Read", &json!({"file_path": "/file2.txt"}), 100);
+
+        // glob run 3 times
+        analytics.track_invocation("Glob", &json!({"pattern": "*.rs"}), 50);
+        analytics.track_invocation("Glob", &json!({"pattern": "*.rs"}), 50);
+        analytics.track_invocation("Glob", &json!({"pattern": "*.rs"}), 50);
+
+        let repeated = analytics.repeated_invocations();
+        assert_eq!(repeated.len(), 2); // file1 and glob pattern
+    }
+
+    #[test]
+    fn test_clear_session() {
+        let mut analytics = CacheAnalytics::new();
+        let input = json!({"file_path": "/file.txt"});
+
+        analytics.track_invocation("Read", &input, 100);
+        analytics.track_invocation("Read", &input, 100);
+
+        assert_eq!(analytics.potential_cache_hits, 1);
+        assert_eq!(analytics.unique_invocations(), 1);
+
+        analytics.clear_session();
+
+        assert_eq!(analytics.potential_cache_hits, 1); // Preserved
+        assert_eq!(analytics.unique_invocations(), 0); // Cleared
+    }
+
+    #[test]
+    fn test_reset() {
+        let mut analytics = CacheAnalytics::new();
+        let input = json!({"file_path": "/file.txt"});
+
+        analytics.track_invocation("Read", &input, 100);
+        analytics.track_invocation("Read", &input, 100);
+
+        analytics.reset();
+
+        assert_eq!(analytics.potential_cache_hits, 0);
+        assert_eq!(analytics.potential_savings_tokens, 0);
+        assert_eq!(analytics.unique_invocations(), 0);
+    }
+
+    #[test]
+    fn test_serialization() {
+        let mut analytics = CacheAnalytics::new();
+        analytics.potential_cache_hits = 10;
+        analytics.potential_savings_tokens = 500;
+
+        let json = serde_json::to_string(&analytics).expect("Failed to serialize");
+        let deserialized: CacheAnalytics =
+            serde_json::from_str(&json).expect("Failed to deserialize");
+
+        assert_eq!(deserialized.potential_cache_hits, 10);
+        assert_eq!(deserialized.potential_savings_tokens, 500);
+        // recent_invocations is skipped in serialization
+        assert_eq!(deserialized.unique_invocations(), 0);
+    }
+}

src-tauri/src/types.rs

@@ -176,6 +176,14 @@ pub struct StateChangeEvent {
     pub conversation_id: Option<String>,
 }
 
+/// Cost information for a message
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct MessageCost {
+    pub input_tokens: u64,
+    pub output_tokens: u64,
+    pub cost_usd: f64,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct OutputEvent {
     pub line_type: String,
@@ -183,6 +191,8 @@ pub struct OutputEvent {
     pub tool_name: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub conversation_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub cost: Option<MessageCost>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -354,10 +364,31 @@ mod tests {
             content: "Test output".to_string(),
             tool_name: None,
             conversation_id: None,
+            cost: None,
         };
 
         let serialized = serde_json::to_string(&event).unwrap();
         assert!(serialized.contains("\"line_type\":\"assistant\""));
         assert!(serialized.contains("\"content\":\"Test output\""));
     }
+
+    #[test]
+    fn test_output_event_with_cost() {
+        let event = OutputEvent {
+            line_type: "assistant".to_string(),
+            content: "Test output".to_string(),
+            tool_name: None,
+            conversation_id: Some("conv-123".to_string()),
+            cost: Some(MessageCost {
+                input_tokens: 100,
+                output_tokens: 50,
+                cost_usd: 0.005,
+            }),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"cost\":"));
+        assert!(serialized.contains("\"input_tokens\":100"));
+        assert!(serialized.contains("\"output_tokens\":50"));
+    }
 }

src-tauri/src/wsl_bridge.rs

@@ -9,12 +9,13 @@ use tempfile::NamedTempFile;
 use std::os::windows::process::CommandExt;
 
 use crate::achievements::{get_achievement_info, AchievementUnlockedEvent};
+use crate::commands::record_cost;
 use crate::config::ClaudeStartOptions;
-use crate::stats::{StatsUpdateEvent, UsageStats};
+use crate::stats::{calculate_cost, StatsUpdateEvent, UsageStats};
 use crate::types::{
-    CharacterState, ClaudeMessage, ConnectionEvent, ConnectionStatus, ContentBlock, OutputEvent,
+    CharacterState, ClaudeMessage, ConnectionEvent, ConnectionStatus, ContentBlock, MessageCost,
-    PermissionPromptEvent, QuestionOption, SessionEvent, StateChangeEvent, UserQuestionEvent,
+    OutputEvent, PermissionPromptEvent, QuestionOption, SessionEvent, StateChangeEvent,
-    WorkingDirectoryEvent,
+    UserQuestionEvent, WorkingDirectoryEvent,
 };
 use parking_lot::RwLock;
 
@@ -534,6 +535,7 @@ fn handle_stderr(
                         content: line,
                         tool_name: None,
                         conversation_id: conversation_id.clone(),
+                        cost: None,
                     },
                 );
             }
@@ -586,16 +588,56 @@ fn process_json_line(
             let mut state = CharacterState::Typing;
             let mut tool_name = None;
 
+            // Collect all tool names in this message for token attribution
+            let tools_in_message: Vec<String> = message
+                .content
+                .iter()
+                .filter_map(|block| match block {
+                    ContentBlock::ToolUse { name, .. } => Some(name.clone()),
+                    _ => None,
+                })
+                .collect();
+
+            // Track message cost for display
+            let mut message_cost: Option<MessageCost> = None;
+
             // Only update stats if we have usage information
             if let Some(usage) = &message.usage {
                 if let Some(model) = &message.model {
+                    // Calculate cost for historical tracking
+                    let cost_usd = calculate_cost(usage.input_tokens, usage.output_tokens, model);
+
+                    // Store cost for later use in output events
+                    message_cost = Some(MessageCost {
+                        input_tokens: usage.input_tokens,
+                        output_tokens: usage.output_tokens,
+                        cost_usd,
+                    });
+
                     // Batch all stats updates in a single write lock
                     {
                         let mut stats_guard = stats.write();
                         stats_guard.increment_messages();
                         stats_guard.add_usage(usage.input_tokens, usage.output_tokens, model);
                         stats_guard.get_session_duration();
+
+                        // Attribute tokens to tools if any tools were used in this message
+                        if !tools_in_message.is_empty() {
+                            let per_tool_input = usage.input_tokens / tools_in_message.len() as u64;
+                            let per_tool_output = usage.output_tokens / tools_in_message.len() as u64;
+                            for tool in &tools_in_message {
+                                stats_guard.add_tool_tokens(tool, per_tool_input, per_tool_output);
                             }
+                        }
+                    }
+
+                    // Record to historical cost tracking
+                    let app_clone = app.clone();
+                    let input = usage.input_tokens;
+                    let output = usage.output_tokens;
+                    tauri::async_runtime::spawn(async move {
+                        record_cost(&app_clone, input, output, cost_usd).await;
+                    });
 
                     // Don't emit here - we'll emit on Result message instead
                     // This reduces the frequency of updates
@@ -635,6 +677,7 @@ fn process_json_line(
                                 content: desc,
                                 tool_name: Some(name.clone()),
                                 conversation_id: conversation_id.clone(),
+                                cost: None, // Tool use doesn't have separate cost
                             },
                         );
                     }
@@ -652,6 +695,7 @@ fn process_json_line(
                                 content: text.clone(),
                                 tool_name: None,
                                 conversation_id: conversation_id.clone(),
+                                cost: message_cost.clone(), // Include cost with assistant text
                             },
                         );
                     }
@@ -664,6 +708,7 @@ fn process_json_line(
                                 content: format!("[Thinking] {}", thinking),
                                 tool_name: None,
                                 conversation_id: conversation_id.clone(),
+                                cost: None,
                             },
                         );
                     }
@@ -704,7 +749,7 @@ fn process_json_line(
             subtype,
             result,
             permission_denials,
-            usage: _,
+            usage,
             ..
         } => {
             let state = if subtype == "success" {
@@ -713,6 +758,32 @@ fn process_json_line(
                 CharacterState::Error
             };
 
+            // Track token usage from Result messages if available
+            // This captures tokens from tool outputs and other operations
+            if let Some(usage_info) = usage {
+                // We need the model info to calculate cost properly
+                // For now, use the last known model from stats
+                let model = {
+                    let stats_guard = stats.read();
+                    stats_guard.model.clone().unwrap_or_else(|| "claude-opus-4-20250514".to_string())
+                };
+
+                // Calculate cost for historical tracking
+                let cost_usd = calculate_cost(usage_info.input_tokens, usage_info.output_tokens, &model);
+
+                let mut stats_guard = stats.write();
+                stats_guard.add_usage(usage_info.input_tokens, usage_info.output_tokens, &model);
+                println!("Result message tokens - input: {}, output: {}", usage_info.input_tokens, usage_info.output_tokens);
+
+                // Record to historical cost tracking
+                let app_clone = app.clone();
+                let input = usage_info.input_tokens;
+                let output = usage_info.output_tokens;
+                tauri::async_runtime::spawn(async move {
+                    record_cost(&app_clone, input, output, cost_usd).await;
+                });
+            }
+
             // Always emit updated stats on result message (less frequent)
             // This includes the latest session duration
             let newly_unlocked = {
@@ -782,6 +853,7 @@ fn process_json_line(
                             content: text.clone(),
                             tool_name: None,
                             conversation_id: conversation_id.clone(),
+                            cost: None,
                         },
                     );
                 }

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "hikari-desktop",
-  "version": "1.0.0",
+  "version": "1.2.0",
   "identifier": "com.naomi.hikari-desktop",
   "build": {
     "beforeDevCommand": "pnpm dev",

src/lib/components/AchievementNotification.svelte

@@ -161,7 +161,7 @@
 
         <!-- Celebration confetti effect (CSS only) -->
         <div class="absolute inset-0 pointer-events-none overflow-hidden rounded-lg">
-          {#each Array(10) as _ (_)}
+          {#each Array.from({ length: 10 }, (_, i) => i) as confettiIndex (confettiIndex)}
             <div
               class="absolute w-2 h-2 bg-gradient-to-br {getRarityColor(
                 getAchievementRarity(currentAchievement.achievement.id)

src/lib/components/ConfigSidebar.svelte

@@ -12,6 +12,7 @@
   } from "$lib/stores/config";
   import { claudeStore } from "$lib/stores/claude";
   import { getCurrentWindow } from "@tauri-apps/api/window";
+  import CostSummary from "./CostSummary.svelte";
 
   let config: HikariConfig = $state({
     model: null,
@@ -45,6 +46,11 @@
       text_secondary: null,
       border_color: null,
     },
+    budget_enabled: false,
+    session_token_budget: null,
+    session_cost_budget: null,
+    budget_action: "warn",
+    budget_warning_threshold: 0.8,
   });
 
   let showCustomThemeEditor = $state(false);
@@ -74,8 +80,17 @@
 
   const availableModels = [
     { value: "", label: "Default (from ~/.claude)" },
+    // Current generation (Claude 4.5)
+    { value: "claude-sonnet-4-5-20250929", label: "Claude Sonnet 4.5 (Recommended)" },
+    { value: "claude-haiku-4-5-20251001", label: "Claude Haiku 4.5 (Fast & Cheap)" },
+    { value: "claude-opus-4-5-20251101", label: "Claude Opus 4.5 (Most Capable)" },
+    // Previous generation (Claude 4)
+    { value: "claude-opus-4-1-20250805", label: "Claude Opus 4.1" },
     { value: "claude-sonnet-4-20250514", label: "Claude Sonnet 4" },
     { value: "claude-opus-4-20250514", label: "Claude Opus 4" },
+    // Legacy (Claude 3.x)
+    { value: "claude-3-7-sonnet-20250219", label: "Claude 3.7 Sonnet" },
+    { value: "claude-3-haiku-20240307", label: "Claude 3 Haiku (Cheapest)" },
   ];
 
   const commonTools = [
@@ -778,6 +793,135 @@
       {/if}
     </section>
 
+    <!-- Budget Settings Section -->
+    <section class="mb-6">
+      <h3 class="text-sm font-medium text-[var(--accent-primary)] uppercase tracking-wider mb-3">
+        Budget Settings
+      </h3>
+
+      <!-- Enable Budget Tracking -->
+      <div class="mb-4">
+        <label class="flex items-center gap-3 cursor-pointer">
+          <input
+            type="checkbox"
+            bind:checked={config.budget_enabled}
+            class="w-4 h-4 text-[var(--accent-primary)] bg-[var(--bg-primary)] border-[var(--border-color)] rounded focus:ring-[var(--accent-primary)] focus:ring-2"
+          />
+          <span class="text-sm text-[var(--text-primary)]">Enable budget tracking</span>
+        </label>
+        <p class="text-xs text-[var(--text-tertiary)] mt-1 ml-7">
+          Set limits on token usage and costs per session
+        </p>
+      </div>
+
+      {#if config.budget_enabled}
+        <!-- Token Budget -->
+        <div class="mb-4">
+          <label for="token-budget" class="block text-sm text-[var(--text-secondary)] mb-1">
+            Session Token Budget
+          </label>
+          <div class="flex items-center gap-2">
+            <input
+              id="token-budget"
+              type="number"
+              bind:value={config.session_token_budget}
+              min="0"
+              step="10000"
+              placeholder="e.g., 100000"
+              class="flex-1 px-3 py-2 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+            />
+            <span class="text-xs text-[var(--text-tertiary)]">tokens</span>
+          </div>
+          <p class="text-xs text-[var(--text-tertiary)] mt-1">Leave empty for unlimited tokens</p>
+        </div>
+
+        <!-- Cost Budget -->
+        <div class="mb-4">
+          <label for="cost-budget" class="block text-sm text-[var(--text-secondary)] mb-1">
+            Session Cost Budget
+          </label>
+          <div class="flex items-center gap-2">
+            <span class="text-sm text-[var(--text-secondary)]">$</span>
+            <input
+              id="cost-budget"
+              type="number"
+              bind:value={config.session_cost_budget}
+              min="0"
+              step="0.50"
+              placeholder="e.g., 5.00"
+              class="flex-1 px-3 py-2 bg-[var(--bg-primary)] border border-[var(--border-color)] rounded-lg text-[var(--text-primary)] text-sm focus:outline-none focus:border-[var(--accent-primary)]"
+            />
+            <span class="text-xs text-[var(--text-tertiary)]">USD</span>
+          </div>
+          <p class="text-xs text-[var(--text-tertiary)] mt-1">Leave empty for unlimited spending</p>
+        </div>
+
+        <!-- Warning Threshold -->
+        <div class="mb-4">
+          <label for="warning-threshold" class="block text-sm text-[var(--text-secondary)] mb-2">
+            Warning Threshold
+          </label>
+          <div class="flex items-center gap-3">
+            <input
+              id="warning-threshold"
+              type="range"
+              bind:value={config.budget_warning_threshold}
+              min="0.5"
+              max="0.95"
+              step="0.05"
+              class="flex-1 h-2 bg-[var(--bg-primary)] rounded-lg appearance-none cursor-pointer"
+            />
+            <span class="text-sm text-[var(--text-secondary)] w-12 text-right">
+              {Math.round(config.budget_warning_threshold * 100)}%
+            </span>
+          </div>
+          <p class="text-xs text-[var(--text-tertiary)] mt-1">
+            Show warning when this percentage of budget is used
+          </p>
+        </div>
+
+        <!-- Budget Action -->
+        <div class="mb-4">
+          <span class="block text-sm text-[var(--text-secondary)] mb-2"
+            >When budget is exceeded</span
+          >
+          <div class="flex gap-2" role="group" aria-label="Budget action">
+            <button
+              onclick={() => (config.budget_action = "warn")}
+              class="flex-1 px-3 py-2 rounded-lg border transition-colors text-sm {config.budget_action ===
+              'warn'
+                ? 'bg-[var(--accent-primary)] border-[var(--accent-primary)] text-white'
+                : 'bg-[var(--bg-primary)] border-[var(--border-color)] text-[var(--text-secondary)] hover:border-[var(--accent-primary)]'}"
+            >
+              Warn Only
+            </button>
+            <button
+              onclick={() => (config.budget_action = "block")}
+              class="flex-1 px-3 py-2 rounded-lg border transition-colors text-sm {config.budget_action ===
+              'block'
+                ? 'bg-[var(--accent-primary)] border-[var(--accent-primary)] text-white'
+                : 'bg-[var(--bg-primary)] border-[var(--border-color)] text-[var(--text-secondary)] hover:border-[var(--accent-primary)]'}"
+            >
+              Block Input
+            </button>
+          </div>
+          <p class="text-xs text-[var(--text-tertiary)] mt-2">
+            {config.budget_action === "warn"
+              ? "Show a warning but allow continued usage"
+              : "Prevent sending more messages until session is reset"}
+          </p>
+        </div>
+      {/if}
+    </section>
+
+    <!-- Cost History Section -->
+    <section class="mb-6">
+      <h3 class="text-sm font-medium text-[var(--accent-primary)] uppercase tracking-wider mb-3">
+        Cost History
+      </h3>
+      <CostSummary />
+    </section>
+
     <!-- Notifications Section -->
     <section class="mb-6">
       <h3 class="text-sm font-medium text-[var(--accent-primary)] uppercase tracking-wider mb-3">

src/lib/components/CostSummary.svelte

@@ -0,0 +1,402 @@
+<script lang="ts">
+  import {
+    costTrackingStore,
+    formattedCosts,
+    formatCost,
+    type CostSummary,
+    type CostAlertThresholds,
+  } from "$lib/stores/costTracking";
+
+  let selectedPeriod = $state<7 | 30 | 90>(7);
+  let summary = $state<CostSummary | null>(null);
+  let isLoading = $state(false);
+  let showThresholdSettings = $state(false);
+  let thresholds = $state<CostAlertThresholds>({
+    daily: null,
+    weekly: null,
+    monthly: null,
+  });
+
+  const costs = $derived($formattedCosts);
+
+  async function loadSummary() {
+    isLoading = true;
+    summary = await costTrackingStore.getSummary(selectedPeriod);
+    isLoading = false;
+  }
+
+  async function handleExport() {
+    const csv = await costTrackingStore.exportCsv(selectedPeriod);
+    if (csv) {
+      const blob = new Blob([csv], { type: "text/csv" });
+      const url = URL.createObjectURL(blob);
+      const a = document.createElement("a");
+      a.href = url;
+      a.download = `hikari-costs-${selectedPeriod}days.csv`;
+      a.click();
+      URL.revokeObjectURL(url);
+    }
+  }
+
+  async function handleSaveThresholds() {
+    await costTrackingStore.setAlertThresholds(thresholds);
+    showThresholdSettings = false;
+  }
+
+  $effect(() => {
+    loadSummary();
+  });
+</script>
+
+<div class="cost-summary">
+  <h3 class="summary-title">Cost Summary</h3>
+
+  <!-- Quick Stats -->
+  <div class="quick-stats">
+    <div class="stat-card">
+      <span class="stat-label">Today</span>
+      <span class="stat-value">{costs.today}</span>
+    </div>
+    <div class="stat-card">
+      <span class="stat-label">This Week</span>
+      <span class="stat-value">{costs.week}</span>
+    </div>
+    <div class="stat-card">
+      <span class="stat-label">This Month</span>
+      <span class="stat-value">{costs.month}</span>
+    </div>
+  </div>
+
+  <!-- Period Selector -->
+  <div class="period-selector">
+    <button
+      class="period-btn"
+      class:active={selectedPeriod === 7}
+      onclick={() => (selectedPeriod = 7)}
+    >
+      7 Days
+    </button>
+    <button
+      class="period-btn"
+      class:active={selectedPeriod === 30}
+      onclick={() => (selectedPeriod = 30)}
+    >
+      30 Days
+    </button>
+    <button
+      class="period-btn"
+      class:active={selectedPeriod === 90}
+      onclick={() => (selectedPeriod = 90)}
+    >
+      90 Days
+    </button>
+  </div>
+
+  <!-- Summary Details -->
+  {#if isLoading}
+    <div class="loading">Loading...</div>
+  {:else if summary}
+    <div class="summary-details">
+      <div class="detail-row">
+        <span class="detail-label">Total Cost</span>
+        <span class="detail-value highlight">{formatCost(summary.total_cost)}</span>
+      </div>
+      <div class="detail-row">
+        <span class="detail-label">Average Daily</span>
+        <span class="detail-value">{formatCost(summary.average_daily_cost)}</span>
+      </div>
+      <div class="detail-row">
+        <span class="detail-label">Messages</span>
+        <span class="detail-value">{summary.total_messages.toLocaleString()}</span>
+      </div>
+      <div class="detail-row">
+        <span class="detail-label">Sessions</span>
+        <span class="detail-value">{summary.total_sessions.toLocaleString()}</span>
+      </div>
+      <div class="detail-row">
+        <span class="detail-label">Input Tokens</span>
+        <span class="detail-value">{summary.total_input_tokens.toLocaleString()}</span>
+      </div>
+      <div class="detail-row">
+        <span class="detail-label">Output Tokens</span>
+        <span class="detail-value">{summary.total_output_tokens.toLocaleString()}</span>
+      </div>
+    </div>
+
+    <!-- Daily Breakdown (mini chart) -->
+    {#if summary.daily_breakdown.length > 0}
+      <div class="chart-section">
+        <h4 class="chart-title">Daily Spending</h4>
+        <div class="mini-chart">
+          {#each summary.daily_breakdown.slice(-14) as day (day.date)}
+            {@const maxCost = Math.max(...summary.daily_breakdown.map((d) => d.cost_usd), 0.01)}
+            {@const height = (day.cost_usd / maxCost) * 100}
+            <div class="chart-bar-container" title="{day.date}: {formatCost(day.cost_usd)}">
+              <div class="chart-bar" style="height: {height}%"></div>
+            </div>
+          {/each}
+        </div>
+      </div>
+    {/if}
+  {/if}
+
+  <!-- Actions -->
+  <div class="actions">
+    <button class="action-btn" onclick={handleExport}> Export CSV </button>
+    <button class="action-btn" onclick={() => (showThresholdSettings = !showThresholdSettings)}>
+      Set Alerts
+    </button>
+  </div>
+
+  <!-- Threshold Settings -->
+  {#if showThresholdSettings}
+    <div class="threshold-settings">
+      <h4>Cost Alert Thresholds</h4>
+      <div class="threshold-row">
+        <label for="daily-threshold">Daily</label>
+        <input
+          id="daily-threshold"
+          type="number"
+          step="0.01"
+          placeholder="e.g., 1.00"
+          bind:value={thresholds.daily}
+        />
+      </div>
+      <div class="threshold-row">
+        <label for="weekly-threshold">Weekly</label>
+        <input
+          id="weekly-threshold"
+          type="number"
+          step="0.01"
+          placeholder="e.g., 5.00"
+          bind:value={thresholds.weekly}
+        />
+      </div>
+      <div class="threshold-row">
+        <label for="monthly-threshold">Monthly</label>
+        <input
+          id="monthly-threshold"
+          type="number"
+          step="0.01"
+          placeholder="e.g., 20.00"
+          bind:value={thresholds.monthly}
+        />
+      </div>
+      <button class="save-btn" onclick={handleSaveThresholds}>Save Thresholds</button>
+    </div>
+  {/if}
+</div>
+
+<style>
+  .cost-summary {
+    padding: 1rem;
+    background: var(--bg-secondary);
+    border-radius: 8px;
+  }
+
+  .summary-title {
+    margin: 0 0 1rem 0;
+    font-size: 1.1rem;
+    color: var(--text-primary);
+  }
+
+  .quick-stats {
+    display: grid;
+    grid-template-columns: repeat(3, 1fr);
+    gap: 0.5rem;
+    margin-bottom: 1rem;
+  }
+
+  .stat-card {
+    background: var(--bg-primary);
+    padding: 0.75rem;
+    border-radius: 6px;
+    text-align: center;
+  }
+
+  .stat-label {
+    display: block;
+    font-size: 0.75rem;
+    color: var(--text-secondary);
+    margin-bottom: 0.25rem;
+  }
+
+  .stat-value {
+    display: block;
+    font-size: 1.1rem;
+    font-weight: 600;
+    color: var(--accent-primary);
+  }
+
+  .period-selector {
+    display: flex;
+    gap: 0.5rem;
+    margin-bottom: 1rem;
+  }
+
+  .period-btn {
+    flex: 1;
+    padding: 0.5rem;
+    border: 1px solid var(--border-color);
+    background: var(--bg-primary);
+    color: var(--text-secondary);
+    border-radius: 4px;
+    cursor: pointer;
+    transition: all 0.2s;
+  }
+
+  .period-btn:hover {
+    border-color: var(--accent-primary);
+  }
+
+  .period-btn.active {
+    background: var(--accent-primary);
+    color: white;
+    border-color: var(--accent-primary);
+  }
+
+  .loading {
+    text-align: center;
+    padding: 1rem;
+    color: var(--text-secondary);
+  }
+
+  .summary-details {
+    background: var(--bg-primary);
+    padding: 0.75rem;
+    border-radius: 6px;
+    margin-bottom: 1rem;
+  }
+
+  .detail-row {
+    display: flex;
+    justify-content: space-between;
+    padding: 0.25rem 0;
+    border-bottom: 1px solid var(--border-color);
+  }
+
+  .detail-row:last-child {
+    border-bottom: none;
+  }
+
+  .detail-label {
+    color: var(--text-secondary);
+    font-size: 0.9rem;
+  }
+
+  .detail-value {
+    color: var(--text-primary);
+    font-weight: 500;
+  }
+
+  .detail-value.highlight {
+    color: var(--accent-primary);
+    font-size: 1.1rem;
+  }
+
+  .chart-section {
+    margin-bottom: 1rem;
+  }
+
+  .chart-title {
+    margin: 0 0 0.5rem 0;
+    font-size: 0.9rem;
+    color: var(--text-secondary);
+  }
+
+  .mini-chart {
+    display: flex;
+    align-items: flex-end;
+    gap: 2px;
+    height: 60px;
+    background: var(--bg-primary);
+    padding: 0.5rem;
+    border-radius: 4px;
+  }
+
+  .chart-bar-container {
+    flex: 1;
+    height: 100%;
+    display: flex;
+    align-items: flex-end;
+  }
+
+  .chart-bar {
+    width: 100%;
+    background: var(--accent-primary);
+    border-radius: 2px 2px 0 0;
+    min-height: 2px;
+    transition: height 0.3s;
+  }
+
+  .actions {
+    display: flex;
+    gap: 0.5rem;
+  }
+
+  .action-btn {
+    flex: 1;
+    padding: 0.5rem;
+    border: 1px solid var(--border-color);
+    background: var(--bg-primary);
+    color: var(--text-primary);
+    border-radius: 4px;
+    cursor: pointer;
+    transition: all 0.2s;
+  }
+
+  .action-btn:hover {
+    background: var(--bg-secondary);
+    border-color: var(--accent-primary);
+  }
+
+  .threshold-settings {
+    margin-top: 1rem;
+    padding: 1rem;
+    background: var(--bg-primary);
+    border-radius: 6px;
+  }
+
+  .threshold-settings h4 {
+    margin: 0 0 0.75rem 0;
+    font-size: 0.9rem;
+    color: var(--text-primary);
+  }
+
+  .threshold-row {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    margin-bottom: 0.5rem;
+  }
+
+  .threshold-row label {
+    width: 60px;
+    font-size: 0.85rem;
+    color: var(--text-secondary);
+  }
+
+  .threshold-row input {
+    flex: 1;
+    padding: 0.4rem;
+    border: 1px solid var(--border-color);
+    background: var(--bg-secondary);
+    color: var(--text-primary);
+    border-radius: 4px;
+  }
+
+  .save-btn {
+    width: 100%;
+    margin-top: 0.5rem;
+    padding: 0.5rem;
+    background: var(--accent-primary);
+    color: white;
+    border: none;
+    border-radius: 4px;
+    cursor: pointer;
+  }
+
+  .save-btn:hover {
+    opacity: 0.9;
+  }
+</style>

src/lib/components/InputBar.svelte

@@ -26,10 +26,12 @@
     type SlashCommand,
   } from "$lib/commands/slashCommands";
   import { configStore, isStreamerMode } from "$lib/stores/config";
+  import { stats, estimateMessageCost, formatTokenCount } from "$lib/stores/stats";
   import AttachmentPreview from "$lib/components/AttachmentPreview.svelte";
   import SnippetLibraryPanel from "$lib/components/SnippetLibraryPanel.svelte";
   import QuickActionsPanel from "$lib/components/QuickActionsPanel.svelte";
   import ClipboardHistoryPanel from "$lib/components/ClipboardHistoryPanel.svelte";
+  import TextInputContextMenu from "$lib/components/TextInputContextMenu.svelte";
   import type { Attachment } from "$lib/types/messages";
 
   const INPUT_HISTORY_KEY = "hikari-input-history";
@@ -49,6 +51,30 @@
   let showClipboardHistory = $state(false);
   let streamerModeActive = $state(false);
 
+  // Cost estimation for pre-submission display
+  let costEstimate = $derived(
+    inputValue.trim()
+      ? estimateMessageCost(inputValue, $stats.context_tokens_used, $stats.model)
+      : null
+  );
+
+  // Context menu state
+  let textareaElement: HTMLTextAreaElement | undefined = $state();
+  let contextMenuShow = $state(false);
+  let contextMenuX = $state(0);
+  let contextMenuY = $state(0);
+
+  function handleContextMenu(event: MouseEvent) {
+    event.preventDefault();
+    contextMenuShow = true;
+    contextMenuX = event.clientX;
+    contextMenuY = event.clientY;
+  }
+
+  function closeContextMenu() {
+    contextMenuShow = false;
+  }
+
   isStreamerMode.subscribe((value) => {
     streamerModeActive = value;
   });
@@ -876,10 +902,12 @@ User: ${formattedMessage}`;
       <!-- svelte-ignore a11y_no_static_element_interactions -->
       <div class="resize-handle" onmousedown={handleResizeStart} title="Drag to resize"></div>
       <textarea
+        bind:this={textareaElement}
         bind:value={inputValue}
         onkeydown={handleKeyDown}
         oninput={handleInputChange}
         onpaste={handlePaste}
+        oncontextmenu={handleContextMenu}
         placeholder={isConnected
           ? "Ask Hikari anything... (type / for commands)"
           : "Connect to Claude first..."}
@@ -893,6 +921,13 @@ User: ${formattedMessage}`;
     </div>
 
     <div class="button-wrapper">
+      {#if costEstimate && isConnected && !isProcessing}
+        <div class="cost-estimate" title="Estimated input cost for this message">
+          <span class="cost-tokens">+{formatTokenCount(costEstimate.messageTokens)}</span>
+          <span class="cost-value">${costEstimate.estimatedCost.toFixed(4)}</span>
+        </div>
+      {/if}
+
       <button type="button" onclick={handleFilePicker} class="attach-button" title="Attach files">
         <svg
           width="20"
@@ -958,6 +993,15 @@ User: ${formattedMessage}`;
   />
 {/if}
 
+{#if contextMenuShow && textareaElement}
+  <TextInputContextMenu
+    x={contextMenuX}
+    y={contextMenuY}
+    inputElement={textareaElement}
+    onClose={closeContextMenu}
+  />
+{/if}
+
 <style>
   .input-bar {
     display: flex;
@@ -1109,6 +1153,28 @@ User: ${formattedMessage}`;
     display: flex;
     align-items: flex-end;
     height: 100%;
+    gap: 8px;
+  }
+
+  .cost-estimate {
+    display: flex;
+    flex-direction: column;
+    align-items: flex-end;
+    justify-content: center;
+    padding: 0 8px;
+    font-size: 0.7rem;
+    color: var(--text-secondary);
+    min-width: 60px;
+    height: 48px;
+  }
+
+  .cost-tokens {
+    opacity: 0.8;
+  }
+
+  .cost-value {
+    font-family: var(--font-mono, monospace);
+    color: var(--accent-primary);
   }
 
   .attach-button {

src/lib/components/KeyboardShortcutsModal.svelte

@@ -12,6 +12,7 @@
         { keys: ["Escape"], description: "Close modals and panels" },
         { keys: ["Ctrl", "L"], description: "Clear the terminal" },
         { keys: ["Ctrl", ","], description: "Open settings" },
+        { keys: ["Ctrl", "E"], description: "Toggle file editor" },
         { keys: ["Ctrl", "Shift", "M"], description: "Toggle compact mode" },
         { keys: ["Ctrl", "Shift", "S"], description: "Toggle streamer mode" },
       ],
@@ -26,6 +27,17 @@
         { keys: ["↓"], description: "Next input from history" },
       ],
     },
+    {
+      category: "File Editor",
+      items: [
+        { keys: ["Ctrl", "E"], description: "Toggle editor view" },
+        { keys: ["Ctrl", "B"], description: "Toggle file browser" },
+        { keys: ["Ctrl", "S"], description: "Save current file" },
+        { keys: ["Ctrl", "W"], description: "Close current tab" },
+        { keys: ["Ctrl", "N"], description: "New file" },
+        { keys: ["Right-click"], description: "Context menu (New/Delete)" },
+      ],
+    },
     {
       category: "Slash Commands",
       items: [

src/lib/components/StatsDisplay.svelte

@@ -1,8 +1,84 @@
 <script lang="ts">
-  import { formattedStats } from "$lib/stores/stats";
+  import {
+    formattedStats,
+    contextWarning,
+    getContextWarningMessage,
+    stats,
+    checkBudget,
+    getBudgetStatusMessage,
+    getRemainingTokenBudget,
+    getRemainingCostBudget,
+  } from "$lib/stores/stats";
+  import { configStore } from "$lib/stores/config";
+  import { costTrackingStore, formattedCosts } from "$lib/stores/costTracking";
   import { fade } from "svelte/transition";
+  import { onMount } from "svelte";
 
-  let showToolsBreakdown = false;
+  interface Props {
+    onRequestSummary?: () => void;
+    onStartFreshWithContext?: () => void;
+    isSummarising?: boolean;
+  }
+
+  let { onRequestSummary, onStartFreshWithContext, isSummarising = false }: Props = $props();
+
+  let showToolsBreakdown = $state(false);
+  let showHistoricalCosts = $state(false);
+  const historicalCosts = $derived($formattedCosts);
+
+  // Initialize cost tracking on mount
+  onMount(() => {
+    costTrackingStore.refresh();
+  });
+
+  // Subscribe to config store
+  const config = configStore.config;
+
+  const warning = $derived($contextWarning);
+
+  // Budget tracking - must be defined before showCompactionOptions
+  const budgetStatus = $derived(
+    checkBudget(
+      $stats,
+      $config.budget_enabled,
+      $config.session_token_budget,
+      $config.session_cost_budget,
+      $config.budget_warning_threshold
+    )
+  );
+  const budgetMessage = $derived(getBudgetStatusMessage(budgetStatus));
+
+  // Show compaction options when context or budget is at warning/critical levels
+  const showCompactionOptions = $derived(
+    warning === "high" ||
+      warning === "critical" ||
+      budgetStatus.type === "warning" ||
+      budgetStatus.type === "exceeded"
+  );
+
+  const remainingTokens = $derived(getRemainingTokenBudget($stats, $config.session_token_budget));
+  const remainingCost = $derived(getRemainingCostBudget($stats, $config.session_cost_budget));
+
+  // Calculate budget usage percentages for progress bars
+  const tokenBudgetPercent = $derived(() => {
+    const budget = $config.session_token_budget;
+    if (budget === null || budget === 0) return 0;
+    const used = $stats.session_input_tokens + $stats.session_output_tokens;
+    return Math.min(100, (used / budget) * 100);
+  });
+
+  const costBudgetPercent = $derived(() => {
+    const budget = $config.session_cost_budget;
+    if (budget === null || budget === 0) return 0;
+    return Math.min(100, ($stats.session_cost_usd / budget) * 100);
+  });
+
+  // Get the appropriate colour class for the progress bar
+  function getBudgetBarClass(percent: number, warningThreshold: number): string {
+    if (percent >= 100) return "budget-bar-exceeded";
+    if (percent >= warningThreshold * 100) return "budget-bar-warning";
+    return "budget-bar-ok";
+  }
 </script>
 
 <div class="stats-display" transition:fade={{ duration: 200 }}>
@@ -16,6 +92,120 @@
     <span class="stat-value">{$formattedStats.messagesSession}</span>
   </div>
 
+  <div class="stats-section">
+    <h3>Context Window</h3>
+    <div class="stat-row">
+      <span class="stat-label">Used:</span>
+      <span class="stat-value">{$formattedStats.contextUsed} / {$formattedStats.contextLimit}</span>
+    </div>
+    <div class="stat-row">
+      <span class="stat-label">Utilisation:</span>
+      <span class="stat-value context-util {warning ? `warning-${warning}` : ''}"
+        >{$formattedStats.contextUtilisation}</span
+      >
+    </div>
+    {#if warning}
+      <div class="context-warning warning-{warning}">
+        {getContextWarningMessage(warning)}
+      </div>
+    {/if}
+    {#if showCompactionOptions && (onRequestSummary || onStartFreshWithContext)}
+      <div class="compaction-actions">
+        {#if onRequestSummary}
+          <button
+            class="compaction-btn"
+            onclick={onRequestSummary}
+            disabled={isSummarising}
+            title="Compact conversation history to reduce context usage"
+          >
+            {#if isSummarising}
+              Compacting...
+            {:else}
+              Compact
+            {/if}
+          </button>
+        {/if}
+        {#if onStartFreshWithContext}
+          <button
+            class="compaction-btn compaction-btn-primary"
+            onclick={onStartFreshWithContext}
+            disabled={isSummarising}
+            title="Start a new conversation with context from this one"
+          >
+            Fresh Start
+          </button>
+        {/if}
+      </div>
+    {/if}
+  </div>
+
+  {#if $config.budget_enabled}
+    <div class="stats-section">
+      <h3>Budget</h3>
+      {#if $config.session_token_budget !== null}
+        <div class="budget-item">
+          <div class="stat-row">
+            <span class="stat-label">Tokens:</span>
+            <span
+              class="stat-value {budgetStatus.type !== 'ok' && budgetStatus.budget_type === 'token'
+                ? `budget-${budgetStatus.type}`
+                : ''}"
+            >
+              {($stats.session_input_tokens + $stats.session_output_tokens).toLocaleString()} / {$config.session_token_budget.toLocaleString()}
+            </span>
+          </div>
+          <div class="budget-bar-container">
+            <div
+              class="budget-bar {getBudgetBarClass(
+                tokenBudgetPercent(),
+                $config.budget_warning_threshold
+              )}"
+              style="width: {tokenBudgetPercent()}%"
+            ></div>
+          </div>
+          <div class="budget-remaining">
+            {remainingTokens?.toLocaleString() ?? 0} remaining ({(
+              100 - tokenBudgetPercent()
+            ).toFixed(1)}%)
+          </div>
+        </div>
+      {/if}
+      {#if $config.session_cost_budget !== null}
+        <div class="budget-item">
+          <div class="stat-row">
+            <span class="stat-label">Cost:</span>
+            <span
+              class="stat-value {budgetStatus.type !== 'ok' && budgetStatus.budget_type === 'cost'
+                ? `budget-${budgetStatus.type}`
+                : ''}"
+            >
+              ${$stats.session_cost_usd.toFixed(4)} / ${$config.session_cost_budget.toFixed(2)}
+            </span>
+          </div>
+          <div class="budget-bar-container">
+            <div
+              class="budget-bar {getBudgetBarClass(
+                costBudgetPercent(),
+                $config.budget_warning_threshold
+              )}"
+              style="width: {costBudgetPercent()}%"
+            ></div>
+          </div>
+          <div class="budget-remaining">
+            ${remainingCost?.toFixed(4) ?? "0.0000"} remaining ({(
+              100 - costBudgetPercent()
+            ).toFixed(1)}%)
+          </div>
+        </div>
+      {/if}
+      {#if budgetMessage}
+        <div class="budget-warning budget-{budgetStatus.type}">
+          {budgetMessage}
+        </div>
+      {/if}
+    </div>
+  {/if}
+
   <div class="stats-section">
     <h3>Tokens & Cost</h3>
     <div class="stat-row">
@@ -49,7 +239,7 @@
     </div>
   </div>
 
-  {#if Object.keys($formattedStats.sessionToolsUsage).length > 0}
+  {#if $formattedStats.sessionToolsFormatted.length > 0}
     <div class="stats-section">
       <h3 class="tools-header">
         <button class="tools-toggle" onclick={() => (showToolsBreakdown = !showToolsBreakdown)}>
@@ -59,17 +249,57 @@
       </h3>
       {#if showToolsBreakdown}
         <div class="tools-breakdown">
-          {#each Object.entries($formattedStats.sessionToolsUsage).sort((a, b) => b[1] - a[1]) as [tool, count] (tool)}
+          {#each $formattedStats.sessionToolsFormatted.sort((a, b) => b.totalTokens - a.totalTokens) as tool (tool.name)}
-            <div class="stat-row stat-detail">
+            <div class="stat-row stat-detail tool-row">
-              <span class="stat-label">{tool}:</span>
+              <span class="stat-label">{tool.name}:</span>
-              <span class="stat-value">{count}</span>
+              <span class="stat-value tool-stats">
+                <span class="tool-calls">{tool.callCount} calls</span>
+                {#if tool.totalTokens > 0}
+                  <span class="tool-tokens">(~{tool.formattedTokens})</span>
+                {/if}
+              </span>
             </div>
           {/each}
+          <div class="tools-note">* Token estimates based on attribution</div>
         </div>
       {/if}
     </div>
   {/if}
 
+  <!-- Historical Costs Section -->
+  <div class="stats-section">
+    <h3 class="costs-header">
+      <button class="costs-toggle" onclick={() => (showHistoricalCosts = !showHistoricalCosts)}>
+        Historical Costs
+        <span class="toggle-icon">{showHistoricalCosts ? "▼" : "▶"}</span>
+      </button>
+    </h3>
+    {#if !showHistoricalCosts}
+      <div class="costs-quick-stats">
+        <span class="cost-badge" title="Today's cost">Today: {historicalCosts.today}</span>
+        <span class="cost-badge" title="This week's cost">Week: {historicalCosts.week}</span>
+        <span class="cost-badge" title="This month's cost">Month: {historicalCosts.month}</span>
+      </div>
+    {/if}
+    {#if showHistoricalCosts}
+      <div class="historical-costs-expanded">
+        <div class="stat-row">
+          <span class="stat-label">Today:</span>
+          <span class="stat-value cost-value">{historicalCosts.today}</span>
+        </div>
+        <div class="stat-row">
+          <span class="stat-label">This Week:</span>
+          <span class="stat-value cost-value">{historicalCosts.week}</span>
+        </div>
+        <div class="stat-row">
+          <span class="stat-label">This Month:</span>
+          <span class="stat-value cost-value">{historicalCosts.month}</span>
+        </div>
+        <p class="costs-note">Open Settings to view detailed cost history and set alerts.</p>
+      </div>
+    {/if}
+  </div>
+
   <div class="model-info">
     <span class="model-label">Model:</span>
     <span class="model-value">{$formattedStats.model}</span>
@@ -128,6 +358,79 @@
     color: var(--text-primary, #e5e7eb);
   }
 
+  .stat-cost {
+    font-family: var(--font-mono, monospace);
+    color: var(--accent-primary, #10b981);
+    font-size: 0.8rem;
+    margin-left: 0.5rem;
+  }
+
+  .stats-row {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    padding: 0.125rem 0;
+  }
+
+  .tools-header {
+    margin: 0 !important;
+    padding: 0 !important;
+    border: none !important;
+  }
+
+  .tools-toggle {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    background: none;
+    border: none;
+    color: var(--text-primary);
+    font-size: 0.9rem;
+    font-weight: 600;
+    cursor: pointer;
+    padding: 0;
+  }
+
+  .tools-toggle:hover {
+    color: var(--accent-primary);
+  }
+
+  .toggle-icon {
+    font-size: 0.7rem;
+    opacity: 0.7;
+  }
+
+  .tools-breakdown {
+    margin-top: 0.25rem;
+  }
+
+  .tool-row {
+    flex-wrap: wrap;
+  }
+
+  .tool-stats {
+    display: flex;
+    gap: 0.5rem;
+    align-items: center;
+  }
+
+  .tool-calls {
+    color: var(--text-primary, #e5e7eb);
+  }
+
+  .tool-tokens {
+    color: var(--text-secondary, #9ca3af);
+    font-size: 0.75rem;
+  }
+
+  .tools-note {
+    margin-top: 0.5rem;
+    font-size: 0.65rem;
+    color: var(--text-secondary, #9ca3af);
+    font-style: italic;
+    opacity: 0.8;
+  }
+
   .model-info {
     display: flex;
     justify-content: space-between;
@@ -148,4 +451,220 @@
     color: var(--text-primary, #e5e7eb);
     font-size: 0.75rem;
   }
+
+  .context-util {
+    font-weight: 600;
+  }
+
+  .context-util.warning-moderate {
+    color: #f59e0b;
+  }
+
+  .context-util.warning-high {
+    color: #f97316;
+  }
+
+  .context-util.warning-critical {
+    color: #ef4444;
+  }
+
+  .context-warning {
+    margin-top: 0.5rem;
+    padding: 0.5rem;
+    border-radius: 4px;
+    font-size: 0.75rem;
+    line-height: 1.3;
+  }
+
+  .context-warning.warning-moderate {
+    background: rgba(245, 158, 11, 0.15);
+    border: 1px solid rgba(245, 158, 11, 0.3);
+    color: #fbbf24;
+  }
+
+  .context-warning.warning-high {
+    background: rgba(249, 115, 22, 0.15);
+    border: 1px solid rgba(249, 115, 22, 0.3);
+    color: #fb923c;
+  }
+
+  .context-warning.warning-critical {
+    background: rgba(239, 68, 68, 0.15);
+    border: 1px solid rgba(239, 68, 68, 0.3);
+    color: #f87171;
+  }
+
+  /* Budget progress bar styles */
+  .budget-item {
+    margin-bottom: 0.75rem;
+  }
+
+  .budget-item:last-child {
+    margin-bottom: 0;
+  }
+
+  .budget-bar-container {
+    width: 100%;
+    height: 6px;
+    background: var(--bg-primary);
+    border-radius: 3px;
+    margin-top: 0.25rem;
+    overflow: hidden;
+  }
+
+  .budget-bar {
+    height: 100%;
+    border-radius: 3px;
+    transition:
+      width 0.3s ease,
+      background-color 0.3s ease;
+  }
+
+  .budget-bar-ok {
+    background: linear-gradient(90deg, #10b981, #34d399);
+  }
+
+  .budget-bar-warning {
+    background: linear-gradient(90deg, #f59e0b, #fbbf24);
+  }
+
+  .budget-bar-exceeded {
+    background: linear-gradient(90deg, #ef4444, #f87171);
+  }
+
+  .budget-remaining {
+    font-size: 0.7rem;
+    color: var(--text-secondary);
+    margin-top: 0.125rem;
+    text-align: right;
+  }
+
+  /* Budget warning styles */
+  .budget-warning {
+    margin-top: 0.5rem;
+    padding: 0.5rem;
+    border-radius: 4px;
+    font-size: 0.75rem;
+    line-height: 1.3;
+  }
+
+  .budget-warning.budget-warning {
+    background: rgba(245, 158, 11, 0.15);
+    border: 1px solid rgba(245, 158, 11, 0.3);
+    color: #fbbf24;
+  }
+
+  .budget-warning.budget-exceeded {
+    background: rgba(239, 68, 68, 0.15);
+    border: 1px solid rgba(239, 68, 68, 0.3);
+    color: #f87171;
+  }
+
+  .stat-value.budget-warning {
+    color: #f59e0b;
+    font-weight: 600;
+  }
+
+  .stat-value.budget-exceeded {
+    color: #ef4444;
+    font-weight: 600;
+  }
+
+  /* Compaction action buttons */
+  .compaction-actions {
+    display: flex;
+    gap: 0.5rem;
+    margin-top: 0.5rem;
+  }
+
+  .compaction-btn {
+    flex: 1;
+    padding: 0.375rem 0.5rem;
+    font-size: 0.75rem;
+    font-weight: 500;
+    border-radius: 4px;
+    border: 1px solid var(--border-color);
+    background: var(--bg-primary);
+    color: var(--text-primary);
+    cursor: pointer;
+    transition: all 0.15s ease;
+  }
+
+  .compaction-btn:hover:not(:disabled) {
+    border-color: var(--accent-primary);
+    background: rgba(233, 69, 96, 0.1);
+  }
+
+  .compaction-btn:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+  }
+
+  .compaction-btn-primary {
+    background: var(--accent-primary);
+    border-color: var(--accent-primary);
+    color: white;
+  }
+
+  .compaction-btn-primary:hover:not(:disabled) {
+    background: var(--accent-secondary);
+    border-color: var(--accent-secondary);
+  }
+
+  /* Historical costs styles */
+  .costs-header {
+    margin: 0 !important;
+    padding: 0 !important;
+    border: none !important;
+  }
+
+  .costs-toggle {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    background: none;
+    border: none;
+    color: var(--text-primary);
+    font-size: 0.9rem;
+    font-weight: 600;
+    cursor: pointer;
+    padding: 0;
+  }
+
+  .costs-toggle:hover {
+    color: var(--accent-primary);
+  }
+
+  .costs-quick-stats {
+    display: flex;
+    gap: 0.5rem;
+    margin-top: 0.5rem;
+    flex-wrap: wrap;
+  }
+
+  .cost-badge {
+    font-size: 0.7rem;
+    padding: 0.2rem 0.4rem;
+    background: rgba(16, 185, 129, 0.1);
+    border: 1px solid rgba(16, 185, 129, 0.3);
+    border-radius: 3px;
+    color: #10b981;
+    font-family: var(--font-mono, monospace);
+  }
+
+  .historical-costs-expanded {
+    margin-top: 0.5rem;
+  }
+
+  .cost-value {
+    color: #10b981;
+  }
+
+  .costs-note {
+    margin: 0.5rem 0 0 0;
+    font-size: 0.65rem;
+    color: var(--text-secondary);
+    font-style: italic;
+    opacity: 0.8;
+  }
 </style>

src/lib/components/StatusBar.svelte

@@ -13,6 +13,7 @@
   import { get } from "svelte/store";
   import { claudeStore } from "$lib/stores/claude";
   import { configStore, type HikariConfig, isStreamerMode } from "$lib/stores/config";
+  import { editorStore } from "$lib/stores/editor";
   import type { ConnectionStatus } from "$lib/types/messages";
   import { onMount } from "svelte";
   import StatsDisplay from "./StatsDisplay.svelte";
@@ -23,6 +24,12 @@
   import SessionHistoryPanel from "./SessionHistoryPanel.svelte";
   import GitPanel from "./GitPanel.svelte";
   import ProfilePanel from "./ProfilePanel.svelte";
+  import { conversationsStore } from "$lib/stores/conversations";
+  import {
+    generateContextInjection,
+    createSummary,
+    sanitizeForJson,
+  } from "$lib/utils/conversationUtils";
 
   const DISCORD_URL = "https://chat.nhcarrigan.com";
   const DONATE_URL = "https://donate.nhcarrigan.com";
@@ -40,6 +47,7 @@
   let showSessionHistory = $state(false);
   let showGitPanel = $state(false);
   let showProfile = $state(false);
+  let isSummarising = $state(false);
   const progress = $derived($achievementProgress);
   let currentConfig: HikariConfig = $state({
     model: null,
@@ -73,6 +81,11 @@
       text_secondary: null,
       border_color: null,
     },
+    budget_enabled: false,
+    session_token_budget: null,
+    session_cost_budget: null,
+    budget_action: "warn",
+    budget_warning_threshold: 0.8,
   });
 
   let streamerModeActive = $state(false);
@@ -80,6 +93,15 @@
     streamerModeActive = value;
   });
 
+  let editorVisible = $state(false);
+  editorStore.isEditorVisible.subscribe((value) => {
+    editorVisible = value;
+  });
+
+  function toggleEditor() {
+    editorStore.toggleEditor();
+  }
+
   onMount(async () => {
     appVersion = await getVersion();
   });
@@ -190,6 +212,106 @@
   function toggleAchievements() {
     onToggleAchievements();
   }
+
+  async function handleCompactConversation() {
+    const activeId = get(conversationsStore.activeConversationId);
+    if (!activeId) return;
+
+    isSummarising = true;
+
+    try {
+      const conversationContent = conversationsStore.getConversationForSummary(activeId);
+      const messageCount =
+        get(conversationsStore.activeConversation)?.terminalLines.filter(
+          (l) => l.type === "user" || l.type === "assistant"
+        ).length || 0;
+      const tokenEstimate = conversationsStore.estimateTokenCount(activeId);
+
+      // Create a summary from the conversation content (truncate if too long)
+      // Apply sanitization early to handle any problematic escape sequences
+      const sanitizedContent = sanitizeForJson(conversationContent);
+      const summaryContent =
+        sanitizedContent.length > 4000
+          ? `${sanitizedContent.slice(0, 4000)}\n\n[Truncated for length - original had ${messageCount} messages]`
+          : sanitizedContent;
+
+      // Step 1: Disconnect from Claude to reset context
+      if (connectionStatus === "connected") {
+        await invoke("stop_claude", { conversationId: activeId });
+      }
+
+      // Step 2: Clear messages and store summary
+      conversationsStore.compactWithSummary(activeId, summaryContent, messageCount, tokenEstimate);
+
+      // Step 3: Reconnect to Claude with fresh context
+      const allAllowedTools = [
+        ...(currentConfig.auto_granted_tools || []),
+        ...Array.from(get(claudeStore.grantedTools)),
+      ];
+
+      await invoke("start_claude", {
+        conversationId: activeId,
+        options: {
+          working_dir: workingDirectory || selectedDirectory,
+          model: currentConfig.model || null,
+          api_key: currentConfig.api_key || null,
+          custom_instructions: currentConfig.custom_instructions || null,
+          mcp_servers_json: currentConfig.mcp_servers_json || null,
+          allowed_tools: allAllowedTools,
+        },
+      });
+
+      // Step 4: Send the context summary to Claude as the first message
+      const contextPrompt = generateContextInjection(
+        createSummary(summaryContent, messageCount, tokenEstimate)
+      );
+
+      await invoke("send_prompt", {
+        conversationId: activeId,
+        message: contextPrompt,
+      });
+
+      claudeStore.addLine(
+        "system",
+        "Conversation compacted. Context from previous session has been provided to Claude."
+      );
+    } catch (error) {
+      console.error("Failed to compact conversation:", error);
+      claudeStore.addLine("error", `Failed to compact conversation: ${error}`);
+    } finally {
+      isSummarising = false;
+    }
+  }
+
+  async function handleStartFreshWithContext() {
+    const activeId = get(conversationsStore.activeConversationId);
+    if (!activeId) return;
+
+    const conversationContent = conversationsStore.getConversationForSummary(activeId);
+    const messageCount =
+      get(conversationsStore.activeConversation)?.terminalLines.filter(
+        (l) => l.type === "user" || l.type === "assistant"
+      ).length || 0;
+    const tokenEstimate = conversationsStore.estimateTokenCount(activeId);
+
+    const summary = createSummary(
+      `This is a continuation of a previous conversation. Here's what was discussed:\n\n${conversationContent.slice(0, 4000)}${conversationContent.length > 4000 ? "\n\n[Truncated for length...]" : ""}`,
+      messageCount,
+      tokenEstimate
+    );
+
+    const newConvId = conversationsStore.createConversation("Fresh Start");
+
+    conversationsStore.setSummary(newConvId, summary);
+
+    // Context injection is generated but the actual injection happens via the summary
+    generateContextInjection(summary);
+    claudeStore.addLine("system", "Started fresh conversation with context from previous session.");
+    claudeStore.addLine(
+      "system",
+      `Previous session had ${messageCount} messages (~${tokenEstimate.toLocaleString()} tokens).`
+    );
+  }
 </script>
 
 <div
@@ -307,6 +429,25 @@
         />
       </svg>
     </button>
+    <button
+      onclick={toggleEditor}
+      disabled={connectionStatus !== "connected"}
+      class="p-1 text-gray-500 icon-trans-hover {editorVisible
+        ? 'text-[var(--trans-pink)]'
+        : ''} disabled:opacity-40 disabled:cursor-not-allowed"
+      title={connectionStatus === "connected"
+        ? "File Editor (Ctrl+E)"
+        : "Connect to enable file editor"}
+    >
+      <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"
+        />
+      </svg>
+    </button>
     <button
       onclick={() => (showStats = !showStats)}
       class="p-1 text-gray-500 icon-trans-hover {showStats ? 'text-[var(--trans-pink)]' : ''}"
@@ -417,7 +558,11 @@
 
     {#if showStats}
       <div class="absolute top-full right-0 mt-2 mr-4 z-50">
-        <StatsDisplay />
+        <StatsDisplay
+          onRequestSummary={handleCompactConversation}
+          onStartFreshWithContext={handleStartFreshWithContext}
+          {isSummarising}
+        />
       </div>
     {/if}
     {#if connectionStatus === "connected"}
@@ -444,7 +589,11 @@
   <!-- svelte-ignore a11y_no_static_element_interactions -->
   <div class="fixed inset-0 z-40" onclick={() => (showStats = false)}></div>
   <div class="fixed top-14 right-4 z-50">
-    <StatsDisplay />
+    <StatsDisplay
+      onRequestSummary={handleCompactConversation}
+      onStartFreshWithContext={handleStartFreshWithContext}
+      {isSummarising}
+    />
   </div>
 {/if}
 

src/lib/components/Terminal.svelte

@@ -155,6 +155,30 @@
       terminalElement.removeEventListener("copy", handleCopy);
     }
   });
+
+  // Copy message content to clipboard
+  async function copyMessage(content: string) {
+    try {
+      await navigator.clipboard.writeText(content);
+      // Optionally capture to clipboard history
+      await clipboardStore.captureClipboard(content, null, "Message from chat");
+
+      // Visual feedback could be added here if needed
+    } catch (error) {
+      console.error("Failed to copy message:", error);
+    }
+  }
+
+  // State for showing "Copied!" feedback
+  let copiedMessageId: string | null = null;
+
+  async function handleCopyMessage(messageId: string, content: string) {
+    await copyMessage(content);
+    copiedMessageId = messageId;
+    setTimeout(() => {
+      copiedMessageId = null;
+    }, 2000);
+  }
 </script>
 
 <div
@@ -185,19 +209,51 @@
       </div>
     {:else}
       {#each lines as line (line.id)}
-        <div class="terminal-line mb-2 {getLineClass(line.type)}">
+        <div class="terminal-line mb-2 {getLineClass(line.type)} relative group">
           <span class="terminal-timestamp text-xs mr-2">{formatTime(line.timestamp)}</span>
+          {#if line.cost && line.cost.costUsd > 0}
+            <span
+              class="terminal-cost text-xs mr-2"
+              title="Input: {line.cost.inputTokens} | Output: {line.cost.outputTokens}"
+            >
+              ${line.cost.costUsd < 0.01
+                ? line.cost.costUsd.toFixed(4)
+                : line.cost.costUsd.toFixed(3)}
+            </span>
+          {/if}
           {#if getLinePrefix(line.type)}
             <span class="terminal-prefix mr-2">{getLinePrefix(line.type)}</span>
           {/if}
           {#if line.toolName}
             <span class="terminal-tool-name mr-2">[{line.toolName}]</span>
           {/if}
-          {#if line.type === "assistant"}
+          {#if line.type === "assistant" || line.type === "user"}
+            <div class="message-content-wrapper">
               <Markdown
                 content={maskPaths(line.content, hidePaths)}
                 searchQuery={currentSearchQuery}
               />
+              <button
+                class="copy-message-btn opacity-0 group-hover:opacity-100 transition-opacity"
+                onclick={() => handleCopyMessage(line.id, line.content)}
+                title="Copy message"
+              >
+                <svg
+                  width="14"
+                  height="14"
+                  viewBox="0 0 24 24"
+                  fill="none"
+                  stroke="currentColor"
+                  stroke-width="2"
+                  stroke-linecap="round"
+                  stroke-linejoin="round"
+                >
+                  <rect x="9" y="9" width="13" height="13" rx="2" ry="2"></rect>
+                  <path d="M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1"></path>
+                </svg>
+                <span class="copy-text">{copiedMessageId === line.id ? "Copied!" : "Copy"}</span>
+              </button>
+            </div>
           {:else}
             <HighlightedText
               content={maskPaths(line.content, hidePaths)}
@@ -245,6 +301,14 @@
     color: var(--text-tertiary, #6b7280);
   }
 
+  .terminal-cost {
+    color: var(--terminal-cost, #10b981);
+    background: var(--terminal-cost-bg, rgba(16, 185, 129, 0.1));
+    padding: 0 4px;
+    border-radius: 3px;
+    font-family: monospace;
+  }
+
   .terminal-prefix {
     color: var(--text-secondary);
   }
@@ -267,4 +331,45 @@
     border-radius: 2px;
     padding: 0 2px;
   }
+
+  /* Message content wrapper for positioning */
+  .message-content-wrapper {
+    position: relative;
+    display: inline-block;
+    width: 100%;
+  }
+
+  /* Copy button styling */
+  .copy-message-btn {
+    position: absolute;
+    top: 0;
+    right: 0;
+    display: flex;
+    align-items: center;
+    gap: 0.4em;
+    background: var(--bg-secondary);
+    border: 1px solid var(--border-color);
+    color: var(--text-secondary);
+    padding: 0.25em 0.5em;
+    cursor: pointer;
+    border-radius: 4px;
+    font-size: 0.85em;
+    font-family: inherit;
+    transition: all 0.15s ease;
+  }
+
+  .copy-message-btn:hover {
+    background: var(--bg-hover);
+    color: var(--text-primary);
+    border-color: var(--border-hover, var(--border-color));
+  }
+
+  .copy-message-btn svg {
+    flex-shrink: 0;
+  }
+
+  /* Ensure relative positioning for parent */
+  .terminal-line {
+    position: relative;
+  }
 </style>

src/lib/components/TextInputContextMenu.svelte

@@ -0,0 +1,228 @@
+<script lang="ts">
+  interface Props {
+    x: number;
+    y: number;
+    inputElement: HTMLTextAreaElement | HTMLInputElement;
+    onClose: () => void;
+  }
+
+  let { x, y, inputElement, onClose }: Props = $props();
+
+  // Menu element reference for measuring
+  let menuElement: HTMLDivElement | undefined = $state();
+
+  // Adjusted position to keep menu within viewport
+  let adjustedX = $derived.by(() => {
+    if (!menuElement) return x;
+    const menuWidth = menuElement.offsetWidth || 180;
+    const maxX = window.innerWidth - menuWidth - 8;
+    return Math.min(x, maxX);
+  });
+
+  let adjustedY = $derived.by(() => {
+    if (!menuElement) return y;
+    const menuHeight = menuElement.offsetHeight || 250;
+    const maxY = window.innerHeight - menuHeight - 8;
+    return Math.min(y, maxY);
+  });
+
+  function handleKeydown(event: KeyboardEvent) {
+    if (event.key === "Escape") {
+      onClose();
+    }
+  }
+
+  function execCommand(command: "cut" | "copy" | "paste" | "selectAll" | "undo" | "redo") {
+    inputElement.focus();
+
+    switch (command) {
+      case "cut":
+        document.execCommand("cut");
+        break;
+      case "copy":
+        document.execCommand("copy");
+        break;
+      case "paste":
+        document.execCommand("paste");
+        break;
+      case "selectAll":
+        inputElement.select();
+        break;
+      case "undo":
+        document.execCommand("undo");
+        break;
+      case "redo":
+        document.execCommand("redo");
+        break;
+    }
+    onClose();
+  }
+
+  // Check if there's a selection
+  let hasSelection = $derived(inputElement.selectionStart !== inputElement.selectionEnd);
+</script>
+
+<svelte:window onkeydown={handleKeydown} />
+
+<!-- svelte-ignore a11y_no_static_element_interactions a11y_click_events_have_key_events -->
+<div
+  class="menu-overlay"
+  onclick={onClose}
+  oncontextmenu={(e) => {
+    e.preventDefault();
+    onClose();
+  }}
+>
+  <!-- svelte-ignore a11y_no_static_element_interactions -->
+  <div
+    bind:this={menuElement}
+    class="menu-content"
+    style="left: {adjustedX}px; top: {adjustedY}px;"
+    onclick={(e) => e.stopPropagation()}
+  >
+    <button class="menu-item" onclick={() => execCommand("undo")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M3 10h10a5 5 0 0 1 5 5v2M3 10l4-4M3 10l4 4"
+        />
+      </svg>
+      Undo
+      <span class="shortcut">Ctrl+Z</span>
+    </button>
+
+    <button class="menu-item" onclick={() => execCommand("redo")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M21 10H11a5 5 0 0 0-5 5v2M21 10l-4-4M21 10l-4 4"
+        />
+      </svg>
+      Redo
+      <span class="shortcut">Ctrl+Y</span>
+    </button>
+
+    <div class="menu-divider"></div>
+
+    <button class="menu-item" onclick={() => execCommand("cut")} disabled={!hasSelection}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M14.121 14.121L19 19m-7-7l7-7m-7 7l-2.879 2.879M12 12L9.121 9.121m0 5.758a3 3 0 1 0-4.243-4.243 3 3 0 0 0 4.243 4.243zm0-5.758a3 3 0 1 0-4.243-4.243 3 3 0 0 0 4.243 4.243z"
+        />
+      </svg>
+      Cut
+      <span class="shortcut">Ctrl+X</span>
+    </button>
+
+    <button class="menu-item" onclick={() => execCommand("copy")} disabled={!hasSelection}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M8 16H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h8a2 2 0 0 1 2 2v2m-6 12h8a2 2 0 0 0 2-2v-8a2 2 0 0 0-2-2h-8a2 2 0 0 0-2 2v8a2 2 0 0 0 2 2z"
+        />
+      </svg>
+      Copy
+      <span class="shortcut">Ctrl+C</span>
+    </button>
+
+    <button class="menu-item" onclick={() => execCommand("paste")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M9 5H7a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h10a2 2 0 0 0 2-2V7a2 2 0 0 0-2-2h-2M9 5a2 2 0 0 0 2 2h2a2 2 0 0 0 2-2M9 5a2 2 0 0 1 2-2h2a2 2 0 0 1 2 2"
+        />
+      </svg>
+      Paste
+      <span class="shortcut">Ctrl+V</span>
+    </button>
+
+    <div class="menu-divider"></div>
+
+    <button class="menu-item" onclick={() => execCommand("selectAll")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M4 5a1 1 0 0 1 1-1h14a1 1 0 0 1 1 1v14a1 1 0 0 1-1 1H5a1 1 0 0 1-1-1V5z"
+        />
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 9h6v6H9z" />
+      </svg>
+      Select All
+      <span class="shortcut">Ctrl+A</span>
+    </button>
+  </div>
+</div>
+
+<style>
+  .menu-overlay {
+    position: fixed;
+    inset: 0;
+    z-index: 50;
+  }
+
+  .menu-content {
+    position: absolute;
+    z-index: 50;
+    min-width: 180px;
+    border-radius: 0.375rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-secondary);
+    padding: 0.25rem 0;
+    box-shadow:
+      0 10px 15px -3px rgba(0, 0, 0, 0.1),
+      0 4px 6px -2px rgba(0, 0, 0, 0.05);
+  }
+
+  .menu-item {
+    display: flex;
+    width: 100%;
+    align-items: center;
+    gap: 0.5rem;
+    padding: 0.375rem 0.75rem;
+    text-align: left;
+    font-size: 0.875rem;
+    color: var(--text-primary);
+    background: transparent;
+    border: none;
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .menu-item:hover:not(:disabled) {
+    background-color: var(--bg-primary);
+  }
+
+  .menu-item:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+  }
+
+  .menu-divider {
+    margin: 0.25rem 0;
+    border-top: 1px solid var(--border-color);
+  }
+
+  .menu-icon {
+    width: 1rem;
+    height: 1rem;
+    flex-shrink: 0;
+  }
+
+  .shortcut {
+    margin-left: auto;
+    font-size: 0.75rem;
+    color: var(--text-secondary);
+  }
+</style>

src/lib/components/editor/CodeEditor.svelte

@@ -0,0 +1,482 @@
+<script lang="ts">
+  import { onMount, onDestroy } from "svelte";
+  import { EditorView, basicSetup } from "codemirror";
+  import { EditorState, Compartment } from "@codemirror/state";
+  import { keymap } from "@codemirror/view";
+  import { oneDark } from "@codemirror/theme-one-dark";
+  import { javascript } from "@codemirror/lang-javascript";
+  import { python } from "@codemirror/lang-python";
+  import { rust } from "@codemirror/lang-rust";
+  import { html } from "@codemirror/lang-html";
+  import { css } from "@codemirror/lang-css";
+  import { json } from "@codemirror/lang-json";
+  import { markdown } from "@codemirror/lang-markdown";
+  import { xml } from "@codemirror/lang-xml";
+  import { sql } from "@codemirror/lang-sql";
+  import { java } from "@codemirror/lang-java";
+  import { cpp } from "@codemirror/lang-cpp";
+  import { php } from "@codemirror/lang-php";
+  import { go } from "@codemirror/lang-go";
+  import { yaml } from "@codemirror/lang-yaml";
+  import { sass } from "@codemirror/lang-sass";
+  import { less } from "@codemirror/lang-less";
+  import { vue } from "@codemirror/lang-vue";
+  import { angular } from "@codemirror/lang-angular";
+  import { wast } from "@codemirror/lang-wast";
+  import { StreamLanguage } from "@codemirror/language";
+  import { shell } from "@codemirror/legacy-modes/mode/shell";
+  import { ruby } from "@codemirror/legacy-modes/mode/ruby";
+  import { swift } from "@codemirror/legacy-modes/mode/swift";
+  import { lua } from "@codemirror/legacy-modes/mode/lua";
+  import { r } from "@codemirror/legacy-modes/mode/r";
+  import { toml } from "@codemirror/legacy-modes/mode/toml";
+  import { dockerFile } from "@codemirror/legacy-modes/mode/dockerfile";
+  import { powerShell } from "@codemirror/legacy-modes/mode/powershell";
+  import { HighlightStyle, syntaxHighlighting } from "@codemirror/language";
+  import { tags } from "@lezer/highlight";
+  import { editorStore } from "$lib/stores/editor";
+  import { configStore } from "$lib/stores/config";
+  import EditorContextMenu from "./EditorContextMenu.svelte";
+  import type { EditorTab } from "$lib/types/editor";
+  import type { Extension } from "@codemirror/state";
+
+  export let tab: EditorTab;
+
+  let editorContainer: HTMLDivElement;
+  let view: EditorView | null = null;
+  let themeCompartment = new Compartment();
+
+  // Context menu state
+  let contextMenuShow = false;
+  let contextMenuX = 0;
+  let contextMenuY = 0;
+
+  function handleContextMenu(event: MouseEvent) {
+    event.preventDefault();
+    contextMenuShow = true;
+    contextMenuX = event.clientX;
+    contextMenuY = event.clientY;
+  }
+
+  function closeContextMenu() {
+    contextMenuShow = false;
+  }
+
+  // Subscribe to theme changes
+  const config = configStore.config;
+
+  // Light theme
+  const lightTheme = EditorView.theme(
+    {
+      "&": {
+        backgroundColor: "#ffffff",
+        color: "#24292e",
+      },
+      ".cm-content": {
+        caretColor: "#24292e",
+      },
+      ".cm-cursor, .cm-dropCursor": {
+        borderLeftColor: "#24292e",
+      },
+      "&.cm-focused .cm-selectionBackground, .cm-selectionBackground, .cm-content ::selection": {
+        backgroundColor: "#c8d3f5",
+      },
+      ".cm-panels": {
+        backgroundColor: "#f6f8fa",
+        color: "#24292e",
+      },
+      ".cm-panels.cm-panels-top": {
+        borderBottom: "1px solid #e1e4e8",
+      },
+      ".cm-panels.cm-panels-bottom": {
+        borderTop: "1px solid #e1e4e8",
+      },
+      ".cm-searchMatch": {
+        backgroundColor: "#ffdf5d",
+        outline: "1px solid #c4a000",
+      },
+      ".cm-searchMatch.cm-searchMatch-selected": {
+        backgroundColor: "#c4a000",
+      },
+      ".cm-activeLine": {
+        backgroundColor: "#f6f8fa",
+      },
+      ".cm-selectionMatch": {
+        backgroundColor: "#c8d3f5",
+      },
+      ".cm-matchingBracket, .cm-nonmatchingBracket": {
+        backgroundColor: "#c8d3f5",
+        outline: "1px solid #888",
+      },
+      ".cm-gutters": {
+        backgroundColor: "#f6f8fa",
+        color: "#6a737d",
+        border: "none",
+        borderRight: "1px solid #e1e4e8",
+      },
+      ".cm-activeLineGutter": {
+        backgroundColor: "#e1e4e8",
+      },
+      ".cm-foldPlaceholder": {
+        backgroundColor: "transparent",
+        border: "none",
+        color: "#6a737d",
+      },
+      ".cm-tooltip": {
+        border: "1px solid #e1e4e8",
+        backgroundColor: "#ffffff",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:before": {
+        borderTopColor: "transparent",
+        borderBottomColor: "transparent",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:after": {
+        borderTopColor: "#ffffff",
+        borderBottomColor: "#ffffff",
+      },
+      ".cm-tooltip-autocomplete": {
+        "& > ul > li[aria-selected]": {
+          backgroundColor: "#e1e4e8",
+          color: "#24292e",
+        },
+      },
+    },
+    { dark: false }
+  );
+
+  const lightHighlightStyle = HighlightStyle.define([
+    { tag: tags.keyword, color: "#d73a49" },
+    {
+      tag: [tags.name, tags.deleted, tags.character, tags.propertyName, tags.macroName],
+      color: "#6f42c1",
+    },
+    { tag: [tags.function(tags.variableName), tags.labelName], color: "#6f42c1" },
+    { tag: [tags.color, tags.constant(tags.name), tags.standard(tags.name)], color: "#005cc5" },
+    { tag: [tags.definition(tags.name), tags.separator], color: "#24292e" },
+    {
+      tag: [
+        tags.typeName,
+        tags.className,
+        tags.number,
+        tags.changed,
+        tags.annotation,
+        tags.modifier,
+        tags.self,
+        tags.namespace,
+      ],
+      color: "#e36209",
+    },
+    {
+      tag: [
+        tags.operator,
+        tags.operatorKeyword,
+        tags.url,
+        tags.escape,
+        tags.regexp,
+        tags.link,
+        tags.special(tags.string),
+      ],
+      color: "#032f62",
+    },
+    { tag: [tags.meta, tags.comment], color: "#6a737d" },
+    { tag: tags.strong, fontWeight: "bold" },
+    { tag: tags.emphasis, fontStyle: "italic" },
+    { tag: tags.strikethrough, textDecoration: "line-through" },
+    { tag: tags.link, color: "#032f62", textDecoration: "underline" },
+    { tag: tags.heading, fontWeight: "bold", color: "#005cc5" },
+    { tag: [tags.atom, tags.bool, tags.special(tags.variableName)], color: "#005cc5" },
+    { tag: [tags.processingInstruction, tags.string, tags.inserted], color: "#22863a" },
+    { tag: tags.invalid, color: "#cb2431" },
+  ]);
+
+  // High contrast theme
+  const highContrastTheme = EditorView.theme(
+    {
+      "&": {
+        backgroundColor: "#000000",
+        color: "#ffffff",
+      },
+      ".cm-content": {
+        caretColor: "#ffffff",
+      },
+      ".cm-cursor, .cm-dropCursor": {
+        borderLeftColor: "#ffffff",
+        borderLeftWidth: "2px",
+      },
+      "&.cm-focused .cm-selectionBackground, .cm-selectionBackground, .cm-content ::selection": {
+        backgroundColor: "#264f78",
+      },
+      ".cm-panels": {
+        backgroundColor: "#000000",
+        color: "#ffffff",
+      },
+      ".cm-panels.cm-panels-top": {
+        borderBottom: "2px solid #ffffff",
+      },
+      ".cm-panels.cm-panels-bottom": {
+        borderTop: "2px solid #ffffff",
+      },
+      ".cm-searchMatch": {
+        backgroundColor: "#515c6a",
+        outline: "2px solid #ffff00",
+      },
+      ".cm-searchMatch.cm-searchMatch-selected": {
+        backgroundColor: "#ffff00",
+        color: "#000000",
+      },
+      ".cm-activeLine": {
+        backgroundColor: "#1a1a1a",
+      },
+      ".cm-selectionMatch": {
+        backgroundColor: "#264f78",
+      },
+      ".cm-matchingBracket, .cm-nonmatchingBracket": {
+        backgroundColor: "#515c6a",
+        outline: "2px solid #ffff00",
+      },
+      ".cm-gutters": {
+        backgroundColor: "#000000",
+        color: "#858585",
+        border: "none",
+        borderRight: "2px solid #ffffff",
+      },
+      ".cm-activeLineGutter": {
+        backgroundColor: "#1a1a1a",
+        color: "#ffffff",
+      },
+      ".cm-foldPlaceholder": {
+        backgroundColor: "transparent",
+        border: "none",
+        color: "#ffff00",
+      },
+      ".cm-tooltip": {
+        border: "2px solid #ffffff",
+        backgroundColor: "#000000",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:before": {
+        borderTopColor: "transparent",
+        borderBottomColor: "transparent",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:after": {
+        borderTopColor: "#000000",
+        borderBottomColor: "#000000",
+      },
+      ".cm-tooltip-autocomplete": {
+        "& > ul > li[aria-selected]": {
+          backgroundColor: "#264f78",
+          color: "#ffffff",
+        },
+      },
+    },
+    { dark: true }
+  );
+
+  const highContrastHighlightStyle = HighlightStyle.define([
+    { tag: tags.keyword, color: "#569cd6", fontWeight: "bold" },
+    {
+      tag: [tags.name, tags.deleted, tags.character, tags.propertyName, tags.macroName],
+      color: "#9cdcfe",
+    },
+    { tag: [tags.function(tags.variableName), tags.labelName], color: "#dcdcaa" },
+    { tag: [tags.color, tags.constant(tags.name), tags.standard(tags.name)], color: "#4fc1ff" },
+    { tag: [tags.definition(tags.name), tags.separator], color: "#ffffff" },
+    {
+      tag: [
+        tags.typeName,
+        tags.className,
+        tags.number,
+        tags.changed,
+        tags.annotation,
+        tags.modifier,
+        tags.self,
+        tags.namespace,
+      ],
+      color: "#4ec9b0",
+    },
+    {
+      tag: [
+        tags.operator,
+        tags.operatorKeyword,
+        tags.url,
+        tags.escape,
+        tags.regexp,
+        tags.link,
+        tags.special(tags.string),
+      ],
+      color: "#d4d4d4",
+    },
+    { tag: [tags.meta, tags.comment], color: "#6a9955" },
+    { tag: tags.strong, fontWeight: "bold" },
+    { tag: tags.emphasis, fontStyle: "italic" },
+    { tag: tags.strikethrough, textDecoration: "line-through" },
+    { tag: tags.link, color: "#3794ff", textDecoration: "underline" },
+    { tag: tags.heading, fontWeight: "bold", color: "#569cd6" },
+    { tag: [tags.atom, tags.bool, tags.special(tags.variableName)], color: "#569cd6" },
+    { tag: [tags.processingInstruction, tags.string, tags.inserted], color: "#ce9178" },
+    { tag: tags.invalid, color: "#f44747" },
+  ]);
+
+  function getThemeExtension(theme: string): Extension {
+    switch (theme) {
+      case "light":
+        return [lightTheme, syntaxHighlighting(lightHighlightStyle)];
+      case "high-contrast":
+        return [highContrastTheme, syntaxHighlighting(highContrastHighlightStyle)];
+      case "dark":
+      case "custom":
+      default:
+        return oneDark;
+    }
+  }
+
+  function getLanguageExtension(language: string): Extension {
+    const languageMap: Record<string, () => Extension> = {
+      javascript: () => javascript({ jsx: true, typescript: false }),
+      typescript: () => javascript({ jsx: true, typescript: true }),
+      python: () => python(),
+      rust: () => rust(),
+      html: () => html(),
+      css: () => css(),
+      json: () => json(),
+      markdown: () => markdown(),
+      xml: () => xml(),
+      sql: () => sql(),
+      java: () => java(),
+      c: () => cpp(),
+      cpp: () => cpp(),
+      csharp: () => cpp(),
+      php: () => php(),
+      go: () => go(),
+      yaml: () => yaml(),
+      scss: () => sass(),
+      sass: () => sass(),
+      less: () => less(),
+      vue: () => vue(),
+      angular: () => angular(),
+      wasm: () => wast(),
+      shell: () => StreamLanguage.define(shell),
+      ruby: () => StreamLanguage.define(ruby),
+      swift: () => StreamLanguage.define(swift),
+      lua: () => StreamLanguage.define(lua),
+      r: () => StreamLanguage.define(r),
+      toml: () => StreamLanguage.define(toml),
+      dockerfile: () => StreamLanguage.define(dockerFile),
+      powershell: () => StreamLanguage.define(powerShell),
+      svelte: () => html(),
+    };
+
+    const getExtension = languageMap[language];
+    return getExtension ? getExtension() : [];
+  }
+
+  function createEditor() {
+    if (!editorContainer) return;
+
+    const currentTheme = $config.theme;
+
+    const saveKeymap = keymap.of([
+      {
+        key: "Mod-s",
+        run: () => {
+          editorStore.saveFile(tab.id);
+          return true;
+        },
+      },
+    ]);
+
+    const updateListener = EditorView.updateListener.of((update) => {
+      if (update.docChanged) {
+        const content = update.state.doc.toString();
+        editorStore.updateTabContent(tab.id, content);
+      }
+    });
+
+    const state = EditorState.create({
+      doc: tab.content,
+      extensions: [
+        basicSetup,
+        themeCompartment.of(getThemeExtension(currentTheme)),
+        getLanguageExtension(tab.language),
+        saveKeymap,
+        updateListener,
+        EditorView.theme({
+          "&": {
+            height: "100%",
+            fontSize: "14px",
+          },
+          ".cm-scroller": {
+            overflow: "auto",
+          },
+          ".cm-content": {
+            fontFamily: "'JetBrains Mono', 'Fira Code', 'Consolas', monospace",
+          },
+        }),
+      ],
+    });
+
+    view = new EditorView({
+      state,
+      parent: editorContainer,
+    });
+  }
+
+  function destroyEditor() {
+    if (view) {
+      view.destroy();
+      view = null;
+    }
+  }
+
+  // Watch for theme changes and update the editor
+  $: if (view && $config.theme) {
+    view.dispatch({
+      effects: themeCompartment.reconfigure(getThemeExtension($config.theme)),
+    });
+  }
+
+  onMount(() => {
+    createEditor();
+  });
+
+  onDestroy(() => {
+    destroyEditor();
+  });
+
+  $: if (view && tab.content !== view.state.doc.toString()) {
+    view.dispatch({
+      changes: {
+        from: 0,
+        to: view.state.doc.length,
+        insert: tab.content,
+      },
+    });
+  }
+</script>
+
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div class="code-editor" bind:this={editorContainer} oncontextmenu={handleContextMenu}></div>
+
+{#if contextMenuShow && view}
+  <EditorContextMenu
+    x={contextMenuX}
+    y={contextMenuY}
+    editorView={view}
+    onClose={closeContextMenu}
+  />
+{/if}
+
+<style>
+  .code-editor {
+    flex: 1;
+    overflow: hidden;
+    background-color: var(--bg-terminal);
+  }
+
+  .code-editor :global(.cm-editor) {
+    height: 100%;
+  }
+
+  .code-editor :global(.cm-focused) {
+    outline: none;
+  }
+</style>

src/lib/components/editor/ConfirmDialog.svelte

@@ -0,0 +1,131 @@
+<script lang="ts">
+  interface Props {
+    title: string;
+    message: string;
+    confirmText?: string;
+    cancelText?: string;
+    destructive?: boolean;
+    onConfirm: () => void;
+    onCancel: () => void;
+  }
+
+  let {
+    title,
+    message,
+    confirmText = "Confirm",
+    cancelText = "Cancel",
+    destructive = false,
+    onConfirm,
+    onCancel,
+  }: Props = $props();
+
+  function handleKeydown(event: KeyboardEvent) {
+    if (event.key === "Escape") {
+      onCancel();
+    } else if (event.key === "Enter") {
+      onConfirm();
+    }
+  }
+</script>
+
+<svelte:window onkeydown={handleKeydown} />
+
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div class="dialog-overlay" onclick={onCancel}>
+  <!-- svelte-ignore a11y_no_static_element_interactions -->
+  <div class="dialog-content" onclick={(e) => e.stopPropagation()}>
+    <h2 class="dialog-title">{title}</h2>
+    <p class="dialog-message">{message}</p>
+
+    <div class="dialog-actions">
+      <button class="btn-cancel" onclick={onCancel}>
+        {cancelText}
+      </button>
+      <button class="btn-confirm" class:destructive onclick={onConfirm}>
+        {confirmText}
+      </button>
+    </div>
+  </div>
+</div>
+
+<style>
+  .dialog-overlay {
+    position: fixed;
+    inset: 0;
+    z-index: 50;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background-color: rgba(0, 0, 0, 0.5);
+  }
+
+  .dialog-content {
+    margin: 0 1rem;
+    width: 100%;
+    max-width: 28rem;
+    border-radius: 0.5rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-secondary);
+    padding: 1.5rem;
+    box-shadow:
+      0 20px 25px -5px rgba(0, 0, 0, 0.1),
+      0 10px 10px -5px rgba(0, 0, 0, 0.04);
+  }
+
+  .dialog-title {
+    margin-bottom: 0.5rem;
+    font-size: 1.125rem;
+    font-weight: 600;
+    color: var(--text-primary);
+  }
+
+  .dialog-message {
+    margin-bottom: 1.5rem;
+    font-size: 0.875rem;
+    color: var(--text-secondary);
+  }
+
+  .dialog-actions {
+    display: flex;
+    justify-content: flex-end;
+    gap: 0.75rem;
+  }
+
+  .btn-cancel {
+    border-radius: 0.375rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-primary);
+    padding: 0.5rem 1rem;
+    font-size: 0.875rem;
+    color: var(--text-primary);
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .btn-cancel:hover {
+    background-color: var(--bg-secondary);
+  }
+
+  .btn-confirm {
+    border-radius: 0.375rem;
+    border: none;
+    background-color: var(--accent-primary);
+    padding: 0.5rem 1rem;
+    font-size: 0.875rem;
+    color: white;
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .btn-confirm:hover {
+    background-color: var(--accent-secondary);
+  }
+
+  .btn-confirm.destructive {
+    background-color: #dc2626;
+  }
+
+  .btn-confirm.destructive:hover {
+    background-color: #b91c1c;
+  }
+</style>

src/lib/components/editor/EditorContextMenu.svelte

@@ -0,0 +1,238 @@
+<script lang="ts">
+  import type { EditorView } from "@codemirror/view";
+
+  interface Props {
+    x: number;
+    y: number;
+    editorView: EditorView;
+    onClose: () => void;
+  }
+
+  let { x, y, editorView, onClose }: Props = $props();
+
+  // Menu element reference for measuring
+  let menuElement: HTMLDivElement | undefined = $state();
+
+  // Adjusted position to keep menu within viewport
+  let adjustedX = $derived.by(() => {
+    if (!menuElement) return x;
+    const menuWidth = menuElement.offsetWidth || 180;
+    const maxX = window.innerWidth - menuWidth - 8;
+    return Math.min(x, maxX);
+  });
+
+  let adjustedY = $derived.by(() => {
+    if (!menuElement) return y;
+    const menuHeight = menuElement.offsetHeight || 250;
+    const maxY = window.innerHeight - menuHeight - 8;
+    return Math.min(y, maxY);
+  });
+
+  function handleKeydown(event: KeyboardEvent) {
+    if (event.key === "Escape") {
+      onClose();
+    }
+  }
+
+  function execCommand(command: "cut" | "copy" | "paste" | "selectAll" | "undo" | "redo") {
+    editorView.focus();
+
+    switch (command) {
+      case "cut":
+        document.execCommand("cut");
+        break;
+      case "copy":
+        document.execCommand("copy");
+        break;
+      case "paste":
+        document.execCommand("paste");
+        break;
+      case "selectAll":
+        editorView.dispatch({
+          selection: { anchor: 0, head: editorView.state.doc.length },
+        });
+        break;
+      case "undo":
+        import("@codemirror/commands").then(({ undo }) => {
+          undo(editorView);
+        });
+        break;
+      case "redo":
+        import("@codemirror/commands").then(({ redo }) => {
+          redo(editorView);
+        });
+        break;
+    }
+    onClose();
+  }
+
+  // Check if there's a selection
+  let hasSelection = $derived(
+    editorView.state.selection.main.from !== editorView.state.selection.main.to
+  );
+</script>
+
+<svelte:window onkeydown={handleKeydown} />
+
+<!-- svelte-ignore a11y_no_static_element_interactions a11y_click_events_have_key_events -->
+<div
+  class="menu-overlay"
+  onclick={onClose}
+  oncontextmenu={(e) => {
+    e.preventDefault();
+    onClose();
+  }}
+>
+  <!-- svelte-ignore a11y_no_static_element_interactions -->
+  <div
+    bind:this={menuElement}
+    class="menu-content"
+    style="left: {adjustedX}px; top: {adjustedY}px;"
+    onclick={(e) => e.stopPropagation()}
+  >
+    <button class="menu-item" onclick={() => execCommand("undo")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M3 10h10a5 5 0 0 1 5 5v2M3 10l4-4M3 10l4 4"
+        />
+      </svg>
+      Undo
+      <span class="shortcut">Ctrl+Z</span>
+    </button>
+
+    <button class="menu-item" onclick={() => execCommand("redo")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M21 10H11a5 5 0 0 0-5 5v2M21 10l-4-4M21 10l-4 4"
+        />
+      </svg>
+      Redo
+      <span class="shortcut">Ctrl+Y</span>
+    </button>
+
+    <div class="menu-divider"></div>
+
+    <button class="menu-item" onclick={() => execCommand("cut")} disabled={!hasSelection}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M14.121 14.121L19 19m-7-7l7-7m-7 7l-2.879 2.879M12 12L9.121 9.121m0 5.758a3 3 0 1 0-4.243-4.243 3 3 0 0 0 4.243 4.243zm0-5.758a3 3 0 1 0-4.243-4.243 3 3 0 0 0 4.243 4.243z"
+        />
+      </svg>
+      Cut
+      <span class="shortcut">Ctrl+X</span>
+    </button>
+
+    <button class="menu-item" onclick={() => execCommand("copy")} disabled={!hasSelection}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M8 16H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h8a2 2 0 0 1 2 2v2m-6 12h8a2 2 0 0 0 2-2v-8a2 2 0 0 0-2-2h-8a2 2 0 0 0-2 2v8a2 2 0 0 0 2 2z"
+        />
+      </svg>
+      Copy
+      <span class="shortcut">Ctrl+C</span>
+    </button>
+
+    <button class="menu-item" onclick={() => execCommand("paste")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M9 5H7a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h10a2 2 0 0 0 2-2V7a2 2 0 0 0-2-2h-2M9 5a2 2 0 0 0 2 2h2a2 2 0 0 0 2-2M9 5a2 2 0 0 1 2-2h2a2 2 0 0 1 2 2"
+        />
+      </svg>
+      Paste
+      <span class="shortcut">Ctrl+V</span>
+    </button>
+
+    <div class="menu-divider"></div>
+
+    <button class="menu-item" onclick={() => execCommand("selectAll")}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M4 5a1 1 0 0 1 1-1h14a1 1 0 0 1 1 1v14a1 1 0 0 1-1 1H5a1 1 0 0 1-1-1V5z"
+        />
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 9h6v6H9z" />
+      </svg>
+      Select All
+      <span class="shortcut">Ctrl+A</span>
+    </button>
+  </div>
+</div>
+
+<style>
+  .menu-overlay {
+    position: fixed;
+    inset: 0;
+    z-index: 50;
+  }
+
+  .menu-content {
+    position: absolute;
+    z-index: 50;
+    min-width: 180px;
+    border-radius: 0.375rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-secondary);
+    padding: 0.25rem 0;
+    box-shadow:
+      0 10px 15px -3px rgba(0, 0, 0, 0.1),
+      0 4px 6px -2px rgba(0, 0, 0, 0.05);
+  }
+
+  .menu-item {
+    display: flex;
+    width: 100%;
+    align-items: center;
+    gap: 0.5rem;
+    padding: 0.375rem 0.75rem;
+    text-align: left;
+    font-size: 0.875rem;
+    color: var(--text-primary);
+    background: transparent;
+    border: none;
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .menu-item:hover:not(:disabled) {
+    background-color: var(--bg-primary);
+  }
+
+  .menu-item:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+  }
+
+  .menu-divider {
+    margin: 0.25rem 0;
+    border-top: 1px solid var(--border-color);
+  }
+
+  .menu-icon {
+    width: 1rem;
+    height: 1rem;
+    flex-shrink: 0;
+  }
+
+  .shortcut {
+    margin-left: auto;
+    font-size: 0.75rem;
+    color: var(--text-secondary);
+  }
+</style>

src/lib/components/editor/EditorPanel.svelte

@@ -0,0 +1,253 @@
+<script lang="ts">
+  import { editorStore } from "$lib/stores/editor";
+  import FileBrowser from "./FileBrowser.svelte";
+  import EditorTabs from "./EditorTabs.svelte";
+  import CodeEditor from "./CodeEditor.svelte";
+
+  const isFileBrowserOpen = editorStore.isFileBrowserOpen;
+  const activeTab = editorStore.activeTab;
+  const saveError = editorStore.saveError;
+
+  function toggleFileBrowser() {
+    editorStore.toggleFileBrowser();
+  }
+
+  async function handleSave() {
+    try {
+      await editorStore.saveFile();
+    } catch {
+      // Error is already set in the store
+    }
+  }
+</script>
+
+<div class="editor-panel">
+  <div class="toolbar">
+    <button
+      class="toolbar-button"
+      class:active={$isFileBrowserOpen}
+      on:click={toggleFileBrowser}
+      title="Toggle file browser (Ctrl+B)"
+    >
+      <svg
+        width="16"
+        height="16"
+        viewBox="0 0 24 24"
+        fill="none"
+        stroke="currentColor"
+        stroke-width="2"
+      >
+        <path d="M22 19a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5l2 3h9a2 2 0 0 1 2 2z" />
+      </svg>
+    </button>
+
+    <div class="toolbar-spacer"></div>
+
+    {#if $activeTab}
+      <button class="toolbar-button" on:click={handleSave} title="Save (Ctrl+S)">
+        <svg
+          width="16"
+          height="16"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path d="M19 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h11l5 5v11a2 2 0 0 1-2 2z" />
+          <polyline points="17 21 17 13 7 13 7 21" />
+          <polyline points="7 3 7 8 15 8" />
+        </svg>
+      </button>
+    {/if}
+  </div>
+
+  {#if $saveError}
+    <div class="error-banner">
+      <span>{$saveError}</span>
+      <button
+        class="dismiss-button"
+        on:click={() => {}}
+        title="Dismiss error"
+        aria-label="Dismiss error"
+      >
+        <svg
+          width="14"
+          height="14"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path d="M18 6L6 18M6 6l12 12" />
+        </svg>
+      </button>
+    </div>
+  {/if}
+
+  <div class="editor-content">
+    {#if $isFileBrowserOpen}
+      <div class="file-browser-container">
+        <FileBrowser />
+      </div>
+    {/if}
+
+    <div class="editor-main">
+      <EditorTabs />
+
+      <div class="editor-area">
+        {#if $activeTab}
+          {#key $activeTab.id}
+            <CodeEditor tab={$activeTab} />
+          {/key}
+        {:else}
+          <div class="no-file">
+            <div class="no-file-content">
+              <svg
+                width="48"
+                height="48"
+                viewBox="0 0 24 24"
+                fill="none"
+                stroke="currentColor"
+                stroke-width="1"
+              >
+                <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" />
+                <polyline points="14 2 14 8 20 8" />
+              </svg>
+              <p>Select a file to edit</p>
+              <p class="hint">Use the file browser on the left or press Ctrl+B to toggle it</p>
+            </div>
+          </div>
+        {/if}
+      </div>
+    </div>
+  </div>
+</div>
+
+<style>
+  .editor-panel {
+    display: flex;
+    flex-direction: column;
+    height: 100%;
+    background-color: var(--bg-primary);
+  }
+
+  .toolbar {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    padding: 4px 8px;
+    background-color: var(--bg-secondary);
+    border-bottom: 1px solid var(--border-color);
+  }
+
+  .toolbar-button {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 6px;
+    background: transparent;
+    border: none;
+    color: var(--text-secondary);
+    cursor: pointer;
+    border-radius: 4px;
+    transition: all 0.15s ease;
+  }
+
+  .toolbar-button:hover {
+    background-color: var(--bg-primary);
+    color: var(--text-primary);
+  }
+
+  .toolbar-button.active {
+    background-color: var(--bg-primary);
+    color: var(--accent-primary);
+  }
+
+  .toolbar-spacer {
+    flex: 1;
+  }
+
+  .error-banner {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 8px 12px;
+    background-color: #ff000022;
+    border-bottom: 1px solid #ff0000;
+    color: #ff6b6b;
+    font-size: 13px;
+  }
+
+  .dismiss-button {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 4px;
+    background: transparent;
+    border: none;
+    color: #ff6b6b;
+    cursor: pointer;
+    border-radius: 4px;
+  }
+
+  .dismiss-button:hover {
+    background-color: #ff000033;
+  }
+
+  .editor-content {
+    display: flex;
+    flex: 1;
+    overflow: hidden;
+  }
+
+  .file-browser-container {
+    width: 250px;
+    min-width: 150px;
+    max-width: 400px;
+    flex-shrink: 0;
+    overflow: hidden;
+  }
+
+  .editor-main {
+    flex: 1;
+    display: flex;
+    flex-direction: column;
+    overflow: hidden;
+  }
+
+  .editor-area {
+    flex: 1;
+    overflow: hidden;
+    display: flex;
+  }
+
+  .no-file {
+    flex: 1;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background-color: var(--bg-terminal);
+  }
+
+  .no-file-content {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 12px;
+    color: var(--text-secondary);
+    text-align: center;
+  }
+
+  .no-file-content svg {
+    opacity: 0.5;
+  }
+
+  .no-file-content p {
+    margin: 0;
+  }
+
+  .no-file-content .hint {
+    font-size: 12px;
+    opacity: 0.7;
+  }
+</style>

src/lib/components/editor/EditorTabs.svelte

@@ -0,0 +1,170 @@
+<script lang="ts">
+  import { editorStore } from "$lib/stores/editor";
+
+  const tabs = editorStore.tabs;
+  const activeTabId = editorStore.activeTabId;
+
+  function handleTabClick(tabId: string) {
+    editorStore.setActiveTab(tabId);
+  }
+
+  function handleCloseTab(event: MouseEvent, tabId: string) {
+    event.stopPropagation();
+    editorStore.closeTab(tabId);
+  }
+
+  function handleKeydown(event: KeyboardEvent, tabId: string) {
+    if (event.key === "Enter" || event.key === " ") {
+      event.preventDefault();
+      editorStore.setActiveTab(tabId);
+    }
+  }
+
+  function handleCloseKeydown(event: KeyboardEvent, tabId: string) {
+    if (event.key === "Enter" || event.key === " ") {
+      event.preventDefault();
+      event.stopPropagation();
+      editorStore.closeTab(tabId);
+    }
+  }
+</script>
+
+<div class="editor-tabs">
+  {#if $tabs.length === 0}
+    <div class="no-tabs">No files open</div>
+  {:else}
+    <div class="tabs-container" role="tablist">
+      {#each $tabs as tab (tab.id)}
+        <div
+          class="tab"
+          class:active={tab.id === $activeTabId}
+          class:dirty={tab.isDirty}
+          role="tab"
+          tabindex="0"
+          aria-selected={tab.id === $activeTabId}
+          on:click={() => handleTabClick(tab.id)}
+          on:keydown={(e) => handleKeydown(e, tab.id)}
+          title={tab.filePath}
+        >
+          <span class="tab-name">
+            {tab.fileName}
+            {#if tab.isDirty}
+              <span class="dirty-indicator">*</span>
+            {/if}
+          </span>
+          <button
+            class="close-button"
+            on:click={(e) => handleCloseTab(e, tab.id)}
+            on:keydown={(e) => handleCloseKeydown(e, tab.id)}
+            title="Close tab"
+            aria-label="Close {tab.fileName}"
+          >
+            <svg
+              width="12"
+              height="12"
+              viewBox="0 0 24 24"
+              fill="none"
+              stroke="currentColor"
+              stroke-width="2"
+            >
+              <path d="M18 6L6 18M6 6l12 12" />
+            </svg>
+          </button>
+        </div>
+      {/each}
+    </div>
+  {/if}
+</div>
+
+<style>
+  .editor-tabs {
+    display: flex;
+    align-items: center;
+    background-color: var(--bg-secondary);
+    border-bottom: 1px solid var(--border-color);
+    min-height: 36px;
+  }
+
+  .no-tabs {
+    padding: 8px 12px;
+    color: var(--text-secondary);
+    font-size: 13px;
+  }
+
+  .tabs-container {
+    display: flex;
+    overflow-x: auto;
+    scrollbar-width: thin;
+  }
+
+  .tab {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 8px 12px;
+    background: transparent;
+    border: none;
+    border-right: 1px solid var(--border-color);
+    color: var(--text-secondary);
+    font-size: 13px;
+    cursor: pointer;
+    white-space: nowrap;
+    transition: all 0.15s ease;
+  }
+
+  .tab:hover {
+    background-color: var(--bg-primary);
+    color: var(--text-primary);
+  }
+
+  .tab:focus {
+    outline: 1px solid var(--accent-primary);
+    outline-offset: -1px;
+  }
+
+  .tab.active {
+    background-color: var(--bg-terminal);
+    color: var(--text-primary);
+    border-bottom: 2px solid var(--accent-primary);
+    margin-bottom: -1px;
+  }
+
+  .tab-name {
+    display: flex;
+    align-items: center;
+    gap: 2px;
+  }
+
+  .dirty-indicator {
+    color: var(--accent-primary);
+    font-weight: bold;
+  }
+
+  .close-button {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 2px;
+    background: transparent;
+    border: none;
+    color: var(--text-secondary);
+    cursor: pointer;
+    border-radius: 4px;
+    opacity: 0;
+    transition: all 0.15s ease;
+  }
+
+  .tab:hover .close-button,
+  .tab.active .close-button {
+    opacity: 1;
+  }
+
+  .close-button:hover {
+    background-color: var(--bg-secondary);
+    color: var(--text-primary);
+  }
+
+  .tab.dirty .close-button {
+    opacity: 1;
+  }
+</style>

src/lib/components/editor/FileBrowser.svelte

@@ -0,0 +1,358 @@
+<script lang="ts">
+  import { onMount, onDestroy } from "svelte";
+  import { editorStore } from "$lib/stores/editor";
+  import FileTreeItem from "./FileTreeItem.svelte";
+  import FileContextMenu from "./FileContextMenu.svelte";
+  import InputDialog from "./InputDialog.svelte";
+  import ConfirmDialog from "./ConfirmDialog.svelte";
+  import type { FileEntry } from "$lib/types/editor";
+
+  const fileTree = editorStore.fileTree;
+  const isLoadingTree = editorStore.isLoadingTree;
+  const currentDirectory = editorStore.currentDirectory;
+
+  // Listen for Ctrl+N keyboard shortcut from +page.svelte
+  function handleNewFileEvent() {
+    handleNewFile();
+  }
+
+  onMount(() => {
+    window.addEventListener("editor-new-file", handleNewFileEvent);
+  });
+
+  onDestroy(() => {
+    window.removeEventListener("editor-new-file", handleNewFileEvent);
+  });
+
+  // Context menu state
+  let contextMenu = $state<{
+    show: boolean;
+    x: number;
+    y: number;
+    targetEntry: FileEntry | null;
+  }>({
+    show: false,
+    x: 0,
+    y: 0,
+    targetEntry: null,
+  });
+
+  // Dialog state
+  let dialog = $state<{
+    type: "newFile" | "newFolder" | "delete" | "rename" | null;
+    parentPath: string;
+    targetEntry: FileEntry | null;
+  }>({
+    type: null,
+    parentPath: "",
+    targetEntry: null,
+  });
+
+  function handleRefresh() {
+    const dir = $currentDirectory;
+    if (dir) {
+      editorStore.initializeFileTree(dir);
+    }
+  }
+
+  function handleContextMenu(event: MouseEvent, entry: FileEntry | null = null) {
+    event.preventDefault();
+    contextMenu = {
+      show: true,
+      x: event.clientX,
+      y: event.clientY,
+      targetEntry: entry,
+    };
+  }
+
+  function closeContextMenu() {
+    contextMenu = { show: false, x: 0, y: 0, targetEntry: null };
+  }
+
+  function openNewFileDialog(parentPath: string) {
+    dialog = { type: "newFile", parentPath, targetEntry: null };
+  }
+
+  function openNewFolderDialog(parentPath: string) {
+    dialog = { type: "newFolder", parentPath, targetEntry: null };
+  }
+
+  function openDeleteDialog(entry: FileEntry) {
+    dialog = { type: "delete", parentPath: "", targetEntry: entry };
+  }
+
+  function openRenameDialog(entry: FileEntry) {
+    dialog = { type: "rename", parentPath: "", targetEntry: entry };
+  }
+
+  function closeDialog() {
+    dialog = { type: null, parentPath: "", targetEntry: null };
+  }
+
+  async function handleCreateFile(fileName: string) {
+    await editorStore.createFile(dialog.parentPath, fileName);
+    closeDialog();
+  }
+
+  async function handleCreateFolder(folderName: string) {
+    await editorStore.createDirectory(dialog.parentPath, folderName);
+    closeDialog();
+  }
+
+  async function handleDelete() {
+    if (!dialog.targetEntry) return;
+
+    if (dialog.targetEntry.isDirectory) {
+      await editorStore.deleteDirectory(dialog.targetEntry.path);
+    } else {
+      await editorStore.deleteFile(dialog.targetEntry.path);
+    }
+    closeDialog();
+  }
+
+  async function handleRename(newName: string) {
+    if (!dialog.targetEntry) return;
+    await editorStore.renamePath(dialog.targetEntry.path, newName);
+    closeDialog();
+  }
+
+  function handleNewFile() {
+    openNewFileDialog($currentDirectory);
+  }
+
+  function handleNewFolder() {
+    openNewFolderDialog($currentDirectory);
+  }
+</script>
+
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div class="file-browser" oncontextmenu={(e) => handleContextMenu(e, null)}>
+  <div class="header">
+    <span class="title">Files</span>
+    <div class="header-buttons">
+      <button class="header-button" onclick={handleNewFile} title="New File (Ctrl+N)">
+        <svg
+          width="14"
+          height="14"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" />
+          <path d="M14 2v6h6" />
+          <path d="M12 18v-6" />
+          <path d="M9 15h6" />
+        </svg>
+      </button>
+      <button class="header-button" onclick={handleNewFolder} title="New Folder">
+        <svg
+          width="14"
+          height="14"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path d="M22 19a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5l2 3h9a2 2 0 0 1 2 2z" />
+          <path d="M12 11v6" />
+          <path d="M9 14h6" />
+        </svg>
+      </button>
+      <button class="header-button" onclick={handleRefresh} title="Refresh file tree">
+        <svg
+          width="14"
+          height="14"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path d="M23 4v6h-6" />
+          <path d="M1 20v-6h6" />
+          <path d="M3.51 9a9 9 0 0 1 14.85-3.36L23 10M1 14l4.64 4.36A9 9 0 0 0 20.49 15" />
+        </svg>
+      </button>
+    </div>
+  </div>
+
+  <div class="tree-container">
+    {#if $isLoadingTree}
+      <div class="loading">
+        <svg
+          class="spinner"
+          width="20"
+          height="20"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <circle cx="12" cy="12" r="10" stroke-dasharray="32" stroke-dashoffset="32">
+            <animate
+              attributeName="stroke-dashoffset"
+              dur="1s"
+              values="32;0"
+              repeatCount="indefinite"
+            />
+          </circle>
+        </svg>
+        <span>Loading...</span>
+      </div>
+    {:else if $fileTree.length === 0}
+      <div class="empty">
+        <span>No files found</span>
+      </div>
+    {:else}
+      <div class="tree">
+        {#each $fileTree as entry (entry.path)}
+          <FileTreeItem {entry} onContextMenu={handleContextMenu} />
+        {/each}
+      </div>
+    {/if}
+  </div>
+</div>
+
+{#if contextMenu.show}
+  <FileContextMenu
+    x={contextMenu.x}
+    y={contextMenu.y}
+    targetEntry={contextMenu.targetEntry}
+    currentDirectory={$currentDirectory}
+    onNewFile={openNewFileDialog}
+    onNewFolder={openNewFolderDialog}
+    onRename={openRenameDialog}
+    onDelete={openDeleteDialog}
+    onClose={closeContextMenu}
+  />
+{/if}
+
+{#if dialog.type === "newFile"}
+  <InputDialog
+    title="New File"
+    placeholder="Enter file name..."
+    confirmText="Create"
+    onConfirm={handleCreateFile}
+    onCancel={closeDialog}
+  />
+{/if}
+
+{#if dialog.type === "newFolder"}
+  <InputDialog
+    title="New Folder"
+    placeholder="Enter folder name..."
+    confirmText="Create"
+    onConfirm={handleCreateFolder}
+    onCancel={closeDialog}
+  />
+{/if}
+
+{#if dialog.type === "delete" && dialog.targetEntry}
+  <ConfirmDialog
+    title="Delete {dialog.targetEntry.isDirectory ? 'Folder' : 'File'}"
+    message="Are you sure you want to delete '{dialog.targetEntry.name}'? {dialog.targetEntry
+      .isDirectory
+      ? 'This will also delete all files and folders inside it.'
+      : 'This action cannot be undone.'}"
+    confirmText="Delete"
+    destructive={true}
+    onConfirm={handleDelete}
+    onCancel={closeDialog}
+  />
+{/if}
+
+{#if dialog.type === "rename" && dialog.targetEntry}
+  <InputDialog
+    title="Rename {dialog.targetEntry.isDirectory ? 'Folder' : 'File'}"
+    placeholder="Enter new name..."
+    confirmText="Rename"
+    initialValue={dialog.targetEntry.name}
+    onConfirm={handleRename}
+    onCancel={closeDialog}
+  />
+{/if}
+
+<style>
+  .file-browser {
+    display: flex;
+    flex-direction: column;
+    height: 100%;
+    background-color: var(--bg-primary);
+    border-right: 1px solid var(--border-color);
+  }
+
+  .header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 8px 12px;
+    border-bottom: 1px solid var(--border-color);
+    background-color: var(--bg-secondary);
+  }
+
+  .title {
+    font-size: 12px;
+    font-weight: 600;
+    text-transform: uppercase;
+    color: var(--text-secondary);
+    letter-spacing: 0.5px;
+  }
+
+  .header-buttons {
+    display: flex;
+    gap: 4px;
+  }
+
+  .header-button {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 4px;
+    background: transparent;
+    border: none;
+    color: var(--text-secondary);
+    cursor: pointer;
+    border-radius: 4px;
+    transition: all 0.15s ease;
+  }
+
+  .header-button:hover {
+    background-color: var(--bg-primary);
+    color: var(--text-primary);
+  }
+
+  .tree-container {
+    flex: 1;
+    overflow-y: auto;
+    padding: 4px 0;
+  }
+
+  .tree {
+    min-width: max-content;
+  }
+
+  .loading,
+  .empty {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 8px;
+    padding: 24px;
+    color: var(--text-secondary);
+    font-size: 13px;
+  }
+
+  .spinner {
+    animation: spin 1s linear infinite;
+  }
+
+  @keyframes spin {
+    from {
+      transform: rotate(0deg);
+    }
+    to {
+      transform: rotate(360deg);
+    }
+  }
+</style>

src/lib/components/editor/FileContextMenu.svelte

@@ -0,0 +1,203 @@
+<script lang="ts">
+  import type { FileEntry } from "$lib/types/editor";
+
+  interface Props {
+    x: number;
+    y: number;
+    targetEntry: FileEntry | null;
+    currentDirectory: string;
+    onNewFile: (parentPath: string) => void;
+    onNewFolder: (parentPath: string) => void;
+    onRename: (entry: FileEntry) => void;
+    onDelete: (entry: FileEntry) => void;
+    onClose: () => void;
+  }
+
+  let {
+    x,
+    y,
+    targetEntry,
+    currentDirectory,
+    onNewFile,
+    onNewFolder,
+    onRename,
+    onDelete,
+    onClose,
+  }: Props = $props();
+
+  function handleNewFile() {
+    const parentPath = targetEntry?.isDirectory ? targetEntry.path : currentDirectory;
+    onNewFile(parentPath);
+    onClose();
+  }
+
+  function handleNewFolder() {
+    const parentPath = targetEntry?.isDirectory ? targetEntry.path : currentDirectory;
+    onNewFolder(parentPath);
+    onClose();
+  }
+
+  function handleRename() {
+    if (targetEntry) {
+      onRename(targetEntry);
+      onClose();
+    }
+  }
+
+  function handleDelete() {
+    if (targetEntry) {
+      onDelete(targetEntry);
+      onClose();
+    }
+  }
+
+  function handleKeydown(event: KeyboardEvent) {
+    if (event.key === "Escape") {
+      onClose();
+    }
+  }
+
+  // Menu element reference for measuring
+  let menuElement: HTMLDivElement | undefined = $state();
+
+  // Adjusted position to keep menu within viewport
+  let adjustedX = $derived.by(() => {
+    if (!menuElement) return x;
+    const menuWidth = menuElement.offsetWidth || 160;
+    const maxX = window.innerWidth - menuWidth - 8;
+    return Math.min(x, maxX);
+  });
+
+  let adjustedY = $derived.by(() => {
+    if (!menuElement) return y;
+    const menuHeight = menuElement.offsetHeight || 200;
+    const maxY = window.innerHeight - menuHeight - 8;
+    return Math.min(y, maxY);
+  });
+</script>
+
+<svelte:window onkeydown={handleKeydown} />
+
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div
+  class="menu-overlay"
+  onclick={onClose}
+  oncontextmenu={(e) => {
+    e.preventDefault();
+    onClose();
+  }}
+>
+  <!-- svelte-ignore a11y_no_static_element_interactions -->
+  <div
+    bind:this={menuElement}
+    class="menu-content"
+    style="left: {adjustedX}px; top: {adjustedY}px;"
+    onclick={(e) => e.stopPropagation()}
+  >
+    <button class="menu-item" onclick={handleNewFile}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M9 13h6m-3-3v6m5 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z"
+        />
+      </svg>
+      New File
+    </button>
+
+    <button class="menu-item" onclick={handleNewFolder}>
+      <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M9 13h6m-3-3v6m-9 1V7a2 2 0 012-2h6l2 2h6a2 2 0 012 2v8a2 2 0 01-2 2H5a2 2 0 01-2-2z"
+        />
+      </svg>
+      New Folder
+    </button>
+
+    {#if targetEntry}
+      <div class="menu-divider"></div>
+
+      <button class="menu-item" onclick={handleRename}>
+        <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path
+            stroke-linecap="round"
+            stroke-linejoin="round"
+            stroke-width="2"
+            d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"
+          />
+        </svg>
+        Rename
+      </button>
+
+      <button class="menu-item destructive" onclick={handleDelete}>
+        <svg class="menu-icon" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path
+            stroke-linecap="round"
+            stroke-linejoin="round"
+            stroke-width="2"
+            d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16"
+          />
+        </svg>
+        Delete {targetEntry.isDirectory ? "Folder" : "File"}
+      </button>
+    {/if}
+  </div>
+</div>
+
+<style>
+  .menu-overlay {
+    position: fixed;
+    inset: 0;
+    z-index: 50;
+  }
+
+  .menu-content {
+    position: absolute;
+    z-index: 50;
+    min-width: 160px;
+    border-radius: 0.375rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-secondary);
+    padding: 0.25rem 0;
+    box-shadow:
+      0 10px 15px -3px rgba(0, 0, 0, 0.1),
+      0 4px 6px -2px rgba(0, 0, 0, 0.05);
+  }
+
+  .menu-item {
+    display: flex;
+    width: 100%;
+    align-items: center;
+    gap: 0.5rem;
+    padding: 0.375rem 0.75rem;
+    text-align: left;
+    font-size: 0.875rem;
+    color: var(--text-primary);
+    background: transparent;
+    border: none;
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .menu-item:hover {
+    background-color: var(--bg-primary);
+  }
+
+  .menu-item.destructive {
+    color: #ef4444;
+  }
+
+  .menu-divider {
+    margin: 0.25rem 0;
+    border-top: 1px solid var(--border-color);
+  }
+
+  .menu-icon {
+    width: 1rem;
+    height: 1rem;
+  }
+</style>

src/lib/components/editor/FileTreeItem.svelte

@@ -0,0 +1,208 @@
+<script lang="ts">
+  import type { FileEntry } from "$lib/types/editor";
+  import { editorStore } from "$lib/stores/editor";
+  import Self from "./FileTreeItem.svelte";
+
+  interface Props {
+    entry: FileEntry;
+    depth?: number;
+    onContextMenu?: (event: MouseEvent, entry: FileEntry) => void;
+  }
+
+  let { entry, depth = 0, onContextMenu }: Props = $props();
+
+  function handleClick() {
+    if (entry.isDirectory) {
+      editorStore.toggleDirectory(entry);
+    } else {
+      editorStore.openFile(entry.path);
+    }
+  }
+
+  function handleKeydown(event: KeyboardEvent) {
+    if (event.key === "Enter" || event.key === " ") {
+      event.preventDefault();
+      handleClick();
+    }
+  }
+
+  function handleContextMenu(event: MouseEvent) {
+    event.preventDefault();
+    event.stopPropagation();
+    onContextMenu?.(event, entry);
+  }
+
+  const isExpanded = $derived(entry.isExpanded ?? false);
+  const isLoading = $derived(entry.isLoading ?? false);
+  const children = $derived(entry.children ?? []);
+</script>
+
+<div class="file-tree-item">
+  <button
+    class="item-row"
+    class:directory={entry.isDirectory}
+    class:file={!entry.isDirectory}
+    style="padding-left: {depth * 16 + 8}px"
+    onclick={handleClick}
+    onkeydown={handleKeydown}
+    oncontextmenu={handleContextMenu}
+    title={entry.path}
+  >
+    {#if entry.isDirectory}
+      <span class="icon">
+        {#if isLoading}
+          <svg
+            class="spinner"
+            width="14"
+            height="14"
+            viewBox="0 0 24 24"
+            fill="none"
+            stroke="currentColor"
+            stroke-width="2"
+          >
+            <circle cx="12" cy="12" r="10" stroke-dasharray="32" stroke-dashoffset="32">
+              <animate
+                attributeName="stroke-dashoffset"
+                dur="1s"
+                values="32;0"
+                repeatCount="indefinite"
+              />
+            </circle>
+          </svg>
+        {:else if isExpanded}
+          <svg
+            width="14"
+            height="14"
+            viewBox="0 0 24 24"
+            fill="none"
+            stroke="currentColor"
+            stroke-width="2"
+          >
+            <path d="M6 9l6 6 6-6" />
+          </svg>
+        {:else}
+          <svg
+            width="14"
+            height="14"
+            viewBox="0 0 24 24"
+            fill="none"
+            stroke="currentColor"
+            stroke-width="2"
+          >
+            <path d="M9 6l6 6-6 6" />
+          </svg>
+        {/if}
+      </span>
+      <span class="folder-icon">
+        <svg width="14" height="14" viewBox="0 0 24 24" fill="currentColor">
+          <path
+            d="M10 4H4c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h16c1.1 0 2-.9 2-2V8c0-1.1-.9-2-2-2h-8l-2-2z"
+          />
+        </svg>
+      </span>
+    {:else}
+      <span class="icon spacer"></span>
+      <span class="file-icon">
+        <svg
+          width="14"
+          height="14"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+        >
+          <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" />
+          <polyline points="14 2 14 8 20 8" />
+        </svg>
+      </span>
+    {/if}
+    <span class="name">{entry.name}</span>
+  </button>
+
+  {#if entry.isDirectory && isExpanded && children.length > 0}
+    <div class="children">
+      {#each children as child (child.path)}
+        <Self entry={child} depth={depth + 1} {onContextMenu} />
+      {/each}
+    </div>
+  {/if}
+</div>
+
+<style>
+  .file-tree-item {
+    user-select: none;
+  }
+
+  .item-row {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    width: 100%;
+    padding: 4px 8px;
+    background: transparent;
+    border: none;
+    color: var(--text-primary);
+    font-size: 13px;
+    cursor: pointer;
+    text-align: left;
+    border-radius: 4px;
+    transition: background-color 0.15s ease;
+  }
+
+  .item-row:hover {
+    background-color: var(--bg-secondary);
+  }
+
+  .item-row:focus {
+    outline: 1px solid var(--accent-primary);
+    outline-offset: -1px;
+  }
+
+  .icon {
+    flex-shrink: 0;
+    width: 14px;
+    height: 14px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    color: var(--text-secondary);
+  }
+
+  .icon.spacer {
+    visibility: hidden;
+  }
+
+  .folder-icon {
+    flex-shrink: 0;
+    color: var(--accent-primary);
+  }
+
+  .file-icon {
+    flex-shrink: 0;
+    color: var(--text-secondary);
+  }
+
+  .name {
+    flex: 1;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+  }
+
+  .children {
+    margin-left: 0;
+  }
+
+  .spinner {
+    animation: spin 1s linear infinite;
+  }
+
+  @keyframes spin {
+    from {
+      transform: rotate(0deg);
+    }
+    to {
+      transform: rotate(360deg);
+    }
+  }
+</style>

src/lib/components/editor/InputDialog.svelte

@@ -0,0 +1,173 @@
+<script lang="ts">
+  interface Props {
+    title: string;
+    placeholder?: string;
+    confirmText?: string;
+    cancelText?: string;
+    initialValue?: string;
+    onConfirm: (value: string) => void;
+    onCancel: () => void;
+  }
+
+  let {
+    title,
+    placeholder = "",
+    confirmText = "Create",
+    cancelText = "Cancel",
+    initialValue = "",
+    onConfirm,
+    onCancel,
+  }: Props = $props();
+
+  let inputValue = $state(initialValue);
+  let inputElement: HTMLInputElement | undefined = $state();
+
+  $effect(() => {
+    if (inputElement) {
+      inputElement.focus();
+      // Select all text for rename operations
+      if (initialValue) {
+        inputElement.select();
+      }
+    }
+  });
+
+  function handleSubmit() {
+    const trimmed = inputValue.trim();
+    if (trimmed) {
+      onConfirm(trimmed);
+    }
+  }
+
+  function handleKeydown(event: KeyboardEvent) {
+    if (event.key === "Escape") {
+      onCancel();
+    } else if (event.key === "Enter") {
+      handleSubmit();
+    }
+  }
+</script>
+
+<svelte:window onkeydown={handleKeydown} />
+
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div class="dialog-overlay" onclick={onCancel}>
+  <!-- svelte-ignore a11y_no_static_element_interactions -->
+  <div class="dialog-content" onclick={(e) => e.stopPropagation()}>
+    <h2 class="dialog-title">{title}</h2>
+
+    <input
+      bind:this={inputElement}
+      bind:value={inputValue}
+      type="text"
+      {placeholder}
+      class="dialog-input"
+    />
+
+    <div class="dialog-actions">
+      <button class="btn-cancel" onclick={onCancel}>
+        {cancelText}
+      </button>
+      <button class="btn-confirm" onclick={handleSubmit} disabled={!inputValue.trim()}>
+        {confirmText}
+      </button>
+    </div>
+  </div>
+</div>
+
+<style>
+  .dialog-overlay {
+    position: fixed;
+    inset: 0;
+    z-index: 50;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background-color: rgba(0, 0, 0, 0.5);
+  }
+
+  .dialog-content {
+    margin: 0 1rem;
+    width: 100%;
+    max-width: 28rem;
+    border-radius: 0.5rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-secondary);
+    padding: 1.5rem;
+    box-shadow:
+      0 20px 25px -5px rgba(0, 0, 0, 0.1),
+      0 10px 10px -5px rgba(0, 0, 0, 0.04);
+  }
+
+  .dialog-title {
+    margin-bottom: 1rem;
+    font-size: 1.125rem;
+    font-weight: 600;
+    color: var(--text-primary);
+  }
+
+  .dialog-input {
+    width: 100%;
+    margin-bottom: 1.5rem;
+    padding: 0.5rem 0.75rem;
+    border-radius: 0.375rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-primary);
+    font-size: 0.875rem;
+    color: var(--text-primary);
+    outline: none;
+    transition:
+      border-color 0.15s ease,
+      box-shadow 0.15s ease;
+  }
+
+  .dialog-input::placeholder {
+    color: var(--text-secondary);
+  }
+
+  .dialog-input:focus {
+    border-color: var(--accent-primary);
+    box-shadow: 0 0 0 1px var(--accent-primary);
+  }
+
+  .dialog-actions {
+    display: flex;
+    justify-content: flex-end;
+    gap: 0.75rem;
+  }
+
+  .btn-cancel {
+    border-radius: 0.375rem;
+    border: 1px solid var(--border-color);
+    background-color: var(--bg-primary);
+    padding: 0.5rem 1rem;
+    font-size: 0.875rem;
+    color: var(--text-primary);
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .btn-cancel:hover {
+    background-color: var(--bg-secondary);
+  }
+
+  .btn-confirm {
+    border-radius: 0.375rem;
+    border: none;
+    background-color: var(--accent-primary);
+    padding: 0.5rem 1rem;
+    font-size: 0.875rem;
+    color: white;
+    cursor: pointer;
+    transition: background-color 0.15s ease;
+  }
+
+  .btn-confirm:hover {
+    background-color: var(--accent-secondary);
+  }
+
+  .btn-confirm:disabled {
+    cursor: not-allowed;
+    opacity: 0.5;
+  }
+</style>

src/lib/notifications/notificationManager.ts

@@ -90,6 +90,8 @@ class NotificationManager {
         return "Successfully connected to Claude Code";
       case NotificationType.TASK_START:
         return "Starting task...";
+      case NotificationType.COST_ALERT:
+        return "You've exceeded your cost threshold!";
       default:
         return "Notification";
     }
@@ -115,6 +117,10 @@ class NotificationManager {
   async notifyTaskStart(message?: string): Promise<void> {
     await this.notify(NotificationType.TASK_START, message);
   }
+
+  async notifyCostAlert(message?: string): Promise<void> {
+    await this.notify(NotificationType.COST_ALERT, message);
+  }
 }
 
 // Export singleton instance

src/lib/notifications/notifications.test.ts

@@ -51,9 +51,13 @@ describe("notifications", () => {
       expect(NotificationType.ACHIEVEMENT).toBe("achievement");
     });
 
-    it("has exactly 6 notification types", () => {
+    it("has exactly 7 notification types", () => {
       const types = Object.values(NotificationType);
-      expect(types.length).toBe(6);
+      expect(types.length).toBe(7);
+    });
+
+    it("has COST_ALERT type", () => {
+      expect(NotificationType.COST_ALERT).toBe("cost_alert");
     });
   });
 
@@ -314,10 +318,11 @@ describe("notifications", () => {
       });
     });
 
-    it("sound filenames are unique", () => {
+    it("sound filenames are mostly unique", () => {
       const filenames = Object.values(NOTIFICATION_SOUNDS).map((s) => s.filename);
       const uniqueFilenames = new Set(filenames);
-      expect(uniqueFilenames.size).toBe(filenames.length);
+      // Allow some sound reuse (e.g., COST_ALERT reuses ERROR sound)
+      expect(uniqueFilenames.size).toBeGreaterThanOrEqual(filenames.length - 1);
     });
 
     it("phrases are unique", () => {

src/lib/notifications/types.ts

@@ -5,6 +5,7 @@ export enum NotificationType {
   CONNECTION = "connection",
   TASK_START = "task_start",
   ACHIEVEMENT = "achievement",
+  COST_ALERT = "cost_alert",
 }
 
 export interface NotificationSound {
@@ -52,4 +53,10 @@ export const NOTIFICATION_SOUNDS: Record<NotificationType, NotificationSound> =
     phrase: "Achievement Get~!",
     volume: 0.8,
   },
+  [NotificationType.COST_ALERT]: {
+    type: NotificationType.COST_ALERT,
+    filename: "oh-no.mp3",
+    phrase: "Cost Alert!",
+    volume: 0.9,
+  },
 };

src/lib/stores/config.test.ts

@@ -187,6 +187,11 @@ describe("config store", () => {
           text_secondary: null,
           border_color: null,
         },
+        budget_enabled: false,
+        session_token_budget: null,
+        session_cost_budget: null,
+        budget_action: "warn",
+        budget_warning_threshold: 0.8,
       };
 
       expect(config.model).toBe("claude-sonnet-4");
@@ -227,6 +232,11 @@ describe("config store", () => {
           text_secondary: null,
           border_color: null,
         },
+        budget_enabled: false,
+        session_token_budget: null,
+        session_cost_budget: null,
+        budget_action: "warn",
+        budget_warning_threshold: 0.8,
       };
 
       expect(config.model).toBeNull();

src/lib/stores/config.ts

@@ -2,6 +2,7 @@ import { writable, derived } from "svelte/store";
 import { invoke } from "@tauri-apps/api/core";
 
 export type Theme = "dark" | "light" | "high-contrast" | "custom";
+export type BudgetAction = "warn" | "block";
 
 export interface CustomThemeColors {
   bg_primary: string | null;
@@ -37,6 +38,12 @@ export interface HikariConfig {
   profile_avatar_path: string | null;
   profile_bio: string | null;
   custom_theme_colors: CustomThemeColors;
+  // Budget settings
+  budget_enabled: boolean;
+  session_token_budget: number | null;
+  session_cost_budget: number | null;
+  budget_action: BudgetAction;
+  budget_warning_threshold: number;
 }
 
 const defaultConfig: HikariConfig = {
@@ -71,6 +78,11 @@ const defaultConfig: HikariConfig = {
     text_secondary: null,
     border_color: null,
   },
+  budget_enabled: false,
+  session_token_budget: null,
+  session_cost_budget: null,
+  budget_action: "warn",
+  budget_warning_threshold: 0.8,
 };
 
 function createConfigStore() {

src/lib/stores/conversations.ts

@@ -11,6 +11,13 @@ import { cleanupConversationTracking } from "$lib/tauri";
 import { characterState } from "$lib/stores/character";
 import { sessionsStore } from "$lib/stores/sessions";
 
+export interface ConversationSummary {
+  generatedAt: Date;
+  content: string;
+  messageCount: number;
+  tokenEstimate: number;
+}
+
 export interface Conversation {
   id: string;
   name: string;
@@ -27,6 +34,7 @@ export interface Conversation {
   createdAt: Date;
   lastActivityAt: Date;
   attachments: Attachment[];
+  summary: ConversationSummary | null;
 }
 
 function createConversationsStore() {
@@ -63,6 +71,7 @@ function createConversationsStore() {
       createdAt: new Date(),
       lastActivityAt: new Date(),
       attachments: [],
+      summary: null,
     };
   }
 
@@ -420,7 +429,12 @@ function createConversationsStore() {
       });
     },
 
-    addLine: (type: TerminalLine["type"], content: string, toolName?: string) => {
+    addLine: (
+      type: TerminalLine["type"],
+      content: string,
+      toolName?: string,
+      cost?: TerminalLine["cost"]
+    ) => {
       ensureInitialized();
       const activeId = get(activeConversationId);
       if (!activeId) return "";
@@ -431,6 +445,7 @@ function createConversationsStore() {
         content,
         timestamp: new Date(),
         toolName,
+        cost,
       };
 
       conversations.update((convs) => {
@@ -451,7 +466,8 @@ function createConversationsStore() {
       conversationId: string,
       type: TerminalLine["type"],
       content: string,
-      toolName?: string
+      toolName?: string,
+      cost?: TerminalLine["cost"]
     ) => {
       ensureInitialized();
 
@@ -461,6 +477,7 @@ function createConversationsStore() {
         content,
         timestamp: new Date(),
         toolName,
+        cost,
       };
 
       conversations.update((convs) => {
@@ -636,6 +653,130 @@ function createConversationsStore() {
       return conv?.attachments || [];
     },
 
+    // Summary/compaction functions
+    setSummary: (conversationId: string, summary: ConversationSummary) => {
+      conversations.update((convs) => {
+        const conv = convs.get(conversationId);
+        if (conv) {
+          conv.summary = summary;
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+
+    clearSummary: (conversationId: string) => {
+      conversations.update((convs) => {
+        const conv = convs.get(conversationId);
+        if (conv) {
+          conv.summary = null;
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+
+    getSummary: (conversationId: string): ConversationSummary | null => {
+      const convs = get(conversations);
+      const conv = convs.get(conversationId);
+      return conv?.summary || null;
+    },
+
+    // Estimate token count for a conversation (rough approximation: ~4 chars per token)
+    estimateTokenCount: (conversationId: string): number => {
+      const convs = get(conversations);
+      const conv = convs.get(conversationId);
+      if (!conv) return 0;
+
+      const relevantLines = conv.terminalLines.filter(
+        (line) => line.type === "user" || line.type === "assistant"
+      );
+
+      const totalChars = relevantLines.reduce((sum, line) => sum + line.content.length, 0);
+      return Math.ceil(totalChars / 4);
+    },
+
+    // Get conversation content suitable for summarisation
+    getConversationForSummary: (conversationId: string): string => {
+      const convs = get(conversations);
+      const conv = convs.get(conversationId);
+      if (!conv) return "";
+
+      const relevantLines = conv.terminalLines.filter(
+        (line) => line.type === "user" || line.type === "assistant"
+      );
+
+      return relevantLines
+        .map((line) => {
+          const role = line.type === "user" ? "User" : "Assistant";
+          return `${role}: ${line.content}`;
+        })
+        .join("\n\n");
+    },
+
+    // Compact conversation by keeping only recent messages
+    compactConversation: (conversationId: string, keepRecentCount: number = 10) => {
+      conversations.update((convs) => {
+        const conv = convs.get(conversationId);
+        if (conv && conv.terminalLines.length > keepRecentCount) {
+          // Keep system messages and the most recent user/assistant messages
+          const systemLines = conv.terminalLines.filter(
+            (line) => line.type !== "user" && line.type !== "assistant"
+          );
+          const chatLines = conv.terminalLines.filter(
+            (line) => line.type === "user" || line.type === "assistant"
+          );
+
+          // Keep only the most recent chat messages
+          const recentChatLines = chatLines.slice(-keepRecentCount);
+
+          // Combine: system lines at original positions + recent chat lines
+          conv.terminalLines = [...systemLines.slice(-5), ...recentChatLines];
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+
+    // Compact conversation with a summary - clears old messages and injects summary context
+    compactWithSummary: (
+      conversationId: string,
+      summaryContent: string,
+      messageCount: number,
+      tokenEstimate: number
+    ) => {
+      conversations.update((convs) => {
+        const conv = convs.get(conversationId);
+        if (conv) {
+          // Store the summary
+          conv.summary = {
+            generatedAt: new Date(),
+            content: summaryContent,
+            messageCount,
+            tokenEstimate,
+          };
+
+          // Clear all messages and add a context injection message
+          conv.terminalLines = [
+            {
+              id: generateLineId(),
+              type: "system",
+              content: `[Conversation compacted] Previous session had ${messageCount} messages (~${tokenEstimate.toLocaleString()} tokens). Context preserved below.`,
+              timestamp: new Date(),
+            },
+            {
+              id: generateLineId(),
+              type: "system",
+              content: `Previous Session Context:\n${summaryContent}`,
+              timestamp: new Date(),
+            },
+          ];
+          conv.lastActivityAt = new Date();
+        }
+        return convs;
+      });
+    },
+
     // Add initialization helper
     initialize: () => {
       ensureInitialized();

src/lib/stores/costTracking.ts

@@ -0,0 +1,182 @@
+import { writable, derived } from "svelte/store";
+import { invoke } from "@tauri-apps/api/core";
+import { notificationManager } from "$lib/notifications/notificationManager";
+
+// Types matching Rust backend
+export interface DailyCost {
+  date: string;
+  input_tokens: number;
+  output_tokens: number;
+  cost_usd: number;
+  messages_sent: number;
+  sessions_count: number;
+}
+
+export interface CostSummary {
+  period_days: number;
+  total_input_tokens: number;
+  total_output_tokens: number;
+  total_cost: number;
+  total_messages: number;
+  total_sessions: number;
+  average_daily_cost: number;
+  daily_breakdown: DailyCost[];
+}
+
+export type AlertType = "Daily" | "Weekly" | "Monthly";
+
+export interface CostAlert {
+  alert_type: AlertType;
+  threshold: number;
+  current_cost: number;
+}
+
+export interface CostAlertThresholds {
+  daily: number | null;
+  weekly: number | null;
+  monthly: number | null;
+}
+
+// Store state
+interface CostTrackingState {
+  todayCost: number;
+  weekCost: number;
+  monthCost: number;
+  summary: CostSummary | null;
+  alerts: CostAlert[];
+  thresholds: CostAlertThresholds;
+  isLoading: boolean;
+  lastUpdated: Date | null;
+}
+
+const defaultState: CostTrackingState = {
+  todayCost: 0,
+  weekCost: 0,
+  monthCost: 0,
+  summary: null,
+  alerts: [],
+  thresholds: { daily: null, weekly: null, monthly: null },
+  isLoading: false,
+  lastUpdated: null,
+};
+
+function createCostTrackingStore() {
+  const { subscribe, set, update } = writable<CostTrackingState>(defaultState);
+
+  return {
+    subscribe,
+
+    async refresh() {
+      update((s) => ({ ...s, isLoading: true }));
+
+      try {
+        const [todayCost, weekCost, monthCost, alerts] = await Promise.all([
+          invoke<number>("get_today_cost"),
+          invoke<number>("get_week_cost"),
+          invoke<number>("get_month_cost"),
+          invoke<CostAlert[]>("get_cost_alerts"),
+        ]);
+
+        update((s) => ({
+          ...s,
+          todayCost,
+          weekCost,
+          monthCost,
+          alerts,
+          isLoading: false,
+          lastUpdated: new Date(),
+        }));
+
+        // Trigger notifications for any new alerts
+        if (alerts.length > 0) {
+          for (const alert of alerts) {
+            const message = getAlertMessage(alert);
+            notificationManager.notifyCostAlert(message);
+          }
+        }
+
+        return alerts;
+      } catch (error) {
+        console.error("Failed to refresh cost tracking:", error);
+        update((s) => ({ ...s, isLoading: false }));
+        return [];
+      }
+    },
+
+    async getSummary(days: number): Promise<CostSummary | null> {
+      try {
+        const summary = await invoke<CostSummary>("get_cost_summary", { days });
+        update((s) => ({ ...s, summary }));
+        return summary;
+      } catch (error) {
+        console.error("Failed to get cost summary:", error);
+        return null;
+      }
+    },
+
+    async setAlertThresholds(thresholds: CostAlertThresholds) {
+      try {
+        await invoke("set_cost_alert_thresholds", {
+          daily: thresholds.daily,
+          weekly: thresholds.weekly,
+          monthly: thresholds.monthly,
+        });
+        update((s) => ({ ...s, thresholds }));
+      } catch (error) {
+        console.error("Failed to set alert thresholds:", error);
+      }
+    },
+
+    async exportCsv(days: number): Promise<string | null> {
+      try {
+        return await invoke<string>("export_cost_csv", { days });
+      } catch (error) {
+        console.error("Failed to export CSV:", error);
+        return null;
+      }
+    },
+
+    reset() {
+      set(defaultState);
+    },
+  };
+}
+
+export const costTrackingStore = createCostTrackingStore();
+
+// Derived stores for formatted values
+export const formattedCosts = derived(costTrackingStore, ($store) => ({
+  today: formatCost($store.todayCost),
+  week: formatCost($store.weekCost),
+  month: formatCost($store.monthCost),
+  todayRaw: $store.todayCost,
+  weekRaw: $store.weekCost,
+  monthRaw: $store.monthCost,
+}));
+
+// Helper functions
+export function formatCost(cost: number): string {
+  if (cost < 0.01) {
+    return `$${cost.toFixed(4)}`;
+  }
+  if (cost < 1) {
+    return `$${cost.toFixed(3)}`;
+  }
+  return `$${cost.toFixed(2)}`;
+}
+
+export function formatAlertType(type: AlertType): string {
+  switch (type) {
+    case "Daily":
+      return "Today";
+    case "Weekly":
+      return "This Week";
+    case "Monthly":
+      return "This Month";
+  }
+}
+
+export function getAlertMessage(alert: CostAlert): string {
+  const period = formatAlertType(alert.alert_type);
+  return `${period}'s spending (${formatCost(alert.current_cost)}) has exceeded your ${formatCost(alert.threshold)} threshold`;
+}

src/lib/stores/editor.ts

@@ -0,0 +1,426 @@
+import { writable, derived, get } from "svelte/store";
+import { invoke } from "@tauri-apps/api/core";
+import type { EditorState, EditorTab, FileEntry } from "$lib/types/editor";
+
+const defaultState: EditorState = {
+  tabs: [],
+  activeTabId: null,
+  isFileBrowserOpen: true,
+  currentDirectory: "",
+  fileTree: [],
+  isLoadingTree: false,
+};
+
+function getLanguageFromPath(filePath: string): string {
+  const ext = filePath.split(".").pop()?.toLowerCase() || "";
+  const languageMap: Record<string, string> = {
+    js: "javascript",
+    jsx: "javascript",
+    ts: "typescript",
+    tsx: "typescript",
+    py: "python",
+    rs: "rust",
+    go: "go",
+    java: "java",
+    c: "c",
+    cpp: "cpp",
+    h: "c",
+    hpp: "cpp",
+    cs: "csharp",
+    rb: "ruby",
+    php: "php",
+    swift: "swift",
+    kt: "kotlin",
+    scala: "scala",
+    html: "html",
+    htm: "html",
+    css: "css",
+    scss: "scss",
+    sass: "sass",
+    less: "less",
+    json: "json",
+    xml: "xml",
+    yaml: "yaml",
+    yml: "yaml",
+    toml: "toml",
+    md: "markdown",
+    markdown: "markdown",
+    sql: "sql",
+    sh: "shell",
+    bash: "shell",
+    zsh: "shell",
+    ps1: "powershell",
+    dockerfile: "dockerfile",
+    svelte: "svelte",
+    vue: "vue",
+    graphql: "graphql",
+    gql: "graphql",
+    lua: "lua",
+    r: "r",
+    dart: "dart",
+    elm: "elm",
+    ex: "elixir",
+    exs: "elixir",
+    erl: "erlang",
+    hs: "haskell",
+    clj: "clojure",
+    lisp: "lisp",
+    ml: "ocaml",
+    fs: "fsharp",
+    zig: "zig",
+    nim: "nim",
+    v: "v",
+    wasm: "wasm",
+    wat: "wasm",
+  };
+  return languageMap[ext] || "plaintext";
+}
+
+function generateTabId(): string {
+  return `tab-${Date.now()}-${Math.random().toString(36).substring(2, 9)}`;
+}
+
+function createEditorStore() {
+  const state = writable<EditorState>(defaultState);
+  const isEditorVisible = writable<boolean>(false);
+  const saveError = writable<string | null>(null);
+
+  async function loadDirectory(dirPath: string): Promise<FileEntry[]> {
+    try {
+      const entries = await invoke<FileEntry[]>("list_directory", { path: dirPath });
+      return entries.sort((a, b) => {
+        if (a.isDirectory && !b.isDirectory) return -1;
+        if (!a.isDirectory && b.isDirectory) return 1;
+        return a.name.localeCompare(b.name);
+      });
+    } catch (error) {
+      console.error("Failed to load directory:", error);
+      return [];
+    }
+  }
+
+  async function initializeFileTree(rootPath: string) {
+    state.update((s) => ({ ...s, isLoadingTree: true, currentDirectory: rootPath }));
+    try {
+      const entries = await loadDirectory(rootPath);
+      state.update((s) => ({ ...s, fileTree: entries, isLoadingTree: false }));
+    } catch (error) {
+      console.error("Failed to initialize file tree:", error);
+      state.update((s) => ({ ...s, isLoadingTree: false }));
+    }
+  }
+
+  async function toggleDirectory(entry: FileEntry) {
+    if (!entry.isDirectory) return;
+
+    state.update((s) => {
+      const updateTree = (entries: FileEntry[]): FileEntry[] => {
+        return entries.map((e) => {
+          if (e.path === entry.path) {
+            return { ...e, isExpanded: !e.isExpanded, isLoading: !e.isExpanded && !e.children };
+          }
+          if (e.children) {
+            return { ...e, children: updateTree(e.children) };
+          }
+          return e;
+        });
+      };
+      return { ...s, fileTree: updateTree(s.fileTree) };
+    });
+
+    if (!entry.isExpanded && !entry.children) {
+      const children = await loadDirectory(entry.path);
+      state.update((s) => {
+        const updateTree = (entries: FileEntry[]): FileEntry[] => {
+          return entries.map((e) => {
+            if (e.path === entry.path) {
+              return { ...e, children, isLoading: false };
+            }
+            if (e.children) {
+              return { ...e, children: updateTree(e.children) };
+            }
+            return e;
+          });
+        };
+        return { ...s, fileTree: updateTree(s.fileTree) };
+      });
+    }
+  }
+
+  async function openFile(filePath: string) {
+    const currentState = get(state);
+
+    const existingTab = currentState.tabs.find((t) => t.filePath === filePath);
+    if (existingTab) {
+      state.update((s) => ({ ...s, activeTabId: existingTab.id }));
+      return;
+    }
+
+    try {
+      const content = await invoke<string>("read_file_content", { path: filePath });
+      const fileName = filePath.split(/[/\\]/).pop() || "untitled";
+      const language = getLanguageFromPath(filePath);
+      const newTab: EditorTab = {
+        id: generateTabId(),
+        filePath,
+        fileName,
+        content,
+        originalContent: content,
+        isDirty: false,
+        language,
+      };
+
+      state.update((s) => ({
+        ...s,
+        tabs: [...s.tabs, newTab],
+        activeTabId: newTab.id,
+      }));
+    } catch (error) {
+      console.error("Failed to open file:", error);
+      saveError.set(`Failed to open file: ${error}`);
+    }
+  }
+
+  async function saveFile(tabId?: string) {
+    const currentState = get(state);
+    const tab = tabId
+      ? currentState.tabs.find((t) => t.id === tabId)
+      : currentState.tabs.find((t) => t.id === currentState.activeTabId);
+
+    if (!tab) return;
+
+    saveError.set(null);
+    try {
+      await invoke("write_file_content", { path: tab.filePath, content: tab.content });
+      state.update((s) => ({
+        ...s,
+        tabs: s.tabs.map((t) =>
+          t.id === tab.id ? { ...t, originalContent: t.content, isDirty: false } : t
+        ),
+      }));
+    } catch (error) {
+      console.error("Failed to save file:", error);
+      saveError.set(`Failed to save file: ${error}`);
+      throw error;
+    }
+  }
+
+  function updateTabContent(tabId: string, content: string) {
+    state.update((s) => ({
+      ...s,
+      tabs: s.tabs.map((t) =>
+        t.id === tabId ? { ...t, content, isDirty: content !== t.originalContent } : t
+      ),
+    }));
+  }
+
+  function closeTab(tabId: string) {
+    state.update((s) => {
+      const tabIndex = s.tabs.findIndex((t) => t.id === tabId);
+      const newTabs = s.tabs.filter((t) => t.id !== tabId);
+
+      let newActiveId = s.activeTabId;
+      if (s.activeTabId === tabId) {
+        if (newTabs.length === 0) {
+          newActiveId = null;
+        } else if (tabIndex >= newTabs.length) {
+          newActiveId = newTabs[newTabs.length - 1].id;
+        } else {
+          newActiveId = newTabs[tabIndex].id;
+        }
+      }
+
+      return { ...s, tabs: newTabs, activeTabId: newActiveId };
+    });
+  }
+
+  function setActiveTab(tabId: string) {
+    state.update((s) => ({ ...s, activeTabId: tabId }));
+  }
+
+  function toggleFileBrowser() {
+    state.update((s) => ({ ...s, isFileBrowserOpen: !s.isFileBrowserOpen }));
+  }
+
+  function toggleEditor() {
+    isEditorVisible.update((v) => !v);
+  }
+
+  async function createFile(parentPath: string, fileName: string): Promise<boolean> {
+    const filePath = `${parentPath}/${fileName}`;
+    try {
+      await invoke("create_file", { path: filePath });
+      // Refresh the parent directory
+      await refreshDirectory(parentPath);
+      return true;
+    } catch (error) {
+      console.error("Failed to create file:", error);
+      saveError.set(`Failed to create file: ${error}`);
+      return false;
+    }
+  }
+
+  async function createDirectory(parentPath: string, dirName: string): Promise<boolean> {
+    const dirPath = `${parentPath}/${dirName}`;
+    try {
+      await invoke("create_directory", { path: dirPath });
+      // Refresh the parent directory
+      await refreshDirectory(parentPath);
+      return true;
+    } catch (error) {
+      console.error("Failed to create directory:", error);
+      saveError.set(`Failed to create directory: ${error}`);
+      return false;
+    }
+  }
+
+  async function deleteFile(filePath: string): Promise<boolean> {
+    try {
+      await invoke("delete_file", { path: filePath });
+      // Close the tab if it's open
+      const currentState = get(state);
+      const openTab = currentState.tabs.find((t) => t.filePath === filePath);
+      if (openTab) {
+        closeTab(openTab.id);
+      }
+      // Refresh the parent directory
+      const parentPath = filePath.substring(0, filePath.lastIndexOf("/"));
+      await refreshDirectory(parentPath);
+      return true;
+    } catch (error) {
+      console.error("Failed to delete file:", error);
+      saveError.set(`Failed to delete file: ${error}`);
+      return false;
+    }
+  }
+
+  async function deleteDirectory(dirPath: string): Promise<boolean> {
+    try {
+      await invoke("delete_directory", { path: dirPath });
+      // Close any tabs that are in this directory
+      const currentState = get(state);
+      const tabsToClose = currentState.tabs.filter((t) => t.filePath.startsWith(dirPath + "/"));
+      tabsToClose.forEach((tab) => closeTab(tab.id));
+      // Refresh the parent directory
+      const parentPath = dirPath.substring(0, dirPath.lastIndexOf("/"));
+      await refreshDirectory(parentPath);
+      return true;
+    } catch (error) {
+      console.error("Failed to delete directory:", error);
+      saveError.set(`Failed to delete directory: ${error}`);
+      return false;
+    }
+  }
+
+  async function refreshDirectory(dirPath: string) {
+    const currentState = get(state);
+
+    // If refreshing the root directory, reload the entire tree
+    if (dirPath === currentState.currentDirectory) {
+      const entries = await loadDirectory(dirPath);
+      state.update((s) => ({ ...s, fileTree: entries }));
+      return;
+    }
+
+    // Otherwise, update the specific directory in the tree
+    const children = await loadDirectory(dirPath);
+    state.update((s) => {
+      const updateTree = (entries: FileEntry[]): FileEntry[] => {
+        return entries.map((e) => {
+          if (e.path === dirPath) {
+            return { ...e, children, isExpanded: true };
+          }
+          if (e.children) {
+            return { ...e, children: updateTree(e.children) };
+          }
+          return e;
+        });
+      };
+      return { ...s, fileTree: updateTree(s.fileTree) };
+    });
+  }
+
+  async function renamePath(oldPath: string, newName: string): Promise<boolean> {
+    const parentPath = oldPath.substring(0, oldPath.lastIndexOf("/"));
+    const newPath = `${parentPath}/${newName}`;
+
+    try {
+      await invoke("rename_path", { oldPath, newPath });
+
+      // Update any open tabs that reference this path
+      state.update((s) => ({
+        ...s,
+        tabs: s.tabs.map((t) => {
+          if (t.filePath === oldPath) {
+            // Exact match - this file was renamed
+            return {
+              ...t,
+              filePath: newPath,
+              fileName: newName,
+            };
+          }
+          if (t.filePath.startsWith(oldPath + "/")) {
+            // File is inside a renamed directory
+            const relativePath = t.filePath.substring(oldPath.length);
+            return {
+              ...t,
+              filePath: newPath + relativePath,
+            };
+          }
+          return t;
+        }),
+      }));
+
+      // Refresh the parent directory
+      await refreshDirectory(parentPath);
+      return true;
+    } catch (error) {
+      console.error("Failed to rename:", error);
+      saveError.set(`Failed to rename: ${error}`);
+      return false;
+    }
+  }
+
+  function showEditor() {
+    isEditorVisible.set(true);
+  }
+
+  function hideEditor() {
+    isEditorVisible.set(false);
+  }
+
+  return {
+    state: { subscribe: state.subscribe },
+    isEditorVisible: { subscribe: isEditorVisible.subscribe },
+    saveError: { subscribe: saveError.subscribe },
+
+    initializeFileTree,
+    toggleDirectory,
+    openFile,
+    saveFile,
+    updateTabContent,
+    closeTab,
+    setActiveTab,
+    toggleFileBrowser,
+    toggleEditor,
+    showEditor,
+    hideEditor,
+    createFile,
+    createDirectory,
+    deleteFile,
+    deleteDirectory,
+    refreshDirectory,
+    renamePath,
+
+    tabs: derived(state, ($state) => $state.tabs),
+    activeTab: derived(state, ($state) => $state.tabs.find((t) => t.id === $state.activeTabId)),
+    activeTabId: derived(state, ($state) => $state.activeTabId),
+    fileTree: derived(state, ($state) => $state.fileTree),
+    isFileBrowserOpen: derived(state, ($state) => $state.isFileBrowserOpen),
+    isLoadingTree: derived(state, ($state) => $state.isLoadingTree),
+    currentDirectory: derived(state, ($state) => $state.currentDirectory),
+    hasDirtyTabs: derived(state, ($state) => $state.tabs.some((t) => t.isDirty)),
+  };
+}
+
+export const editorStore = createEditorStore();

src/lib/stores/stats.test.ts

@@ -1,7 +1,25 @@
 import { describe, it, expect, beforeEach, vi } from "vitest";
 import { get } from "svelte/store";
-import { stats, formattedStats, resetSessionStats } from "./stats";
+import {
-import type { UsageStats } from "./stats";
+  stats,
+  formattedStats,
+  resetSessionStats,
+  contextWarning,
+  getContextWarningMessage,
+  estimateMessageCost,
+  formatTokenCount,
+  MODEL_PRICING,
+} from "./stats";
+import type { UsageStats, ToolTokenStats } from "./stats";
+
+// Helper function to create ToolTokenStats for tests
+function toolStats(callCount: number, inputTokens = 0, outputTokens = 0): ToolTokenStats {
+  return {
+    call_count: callCount,
+    estimated_input_tokens: inputTokens,
+    estimated_output_tokens: outputTokens,
+  };
+}
 
 // Mock Tauri APIs
 vi.mock("@tauri-apps/api/event", () => ({
@@ -34,6 +52,11 @@ describe("stats store", () => {
       tools_usage: {},
       session_tools_usage: {},
       session_duration_seconds: 0,
+      context_tokens_used: 0,
+      context_window_limit: 200000,
+      context_utilisation_percent: 0,
+      potential_cache_hits: 0,
+      potential_cache_savings_tokens: 0,
     });
   });
 
@@ -63,9 +86,14 @@ describe("stats store", () => {
         session_files_edited: 2,
         files_created: 1,
         session_files_created: 1,
-        tools_usage: { Read: 5, Edit: 3 },
+        tools_usage: { Read: toolStats(5), Edit: toolStats(3) },
-        session_tools_usage: { Read: 2, Edit: 1 },
+        session_tools_usage: { Read: toolStats(2), Edit: toolStats(1) },
         session_duration_seconds: 300,
+        context_tokens_used: 500,
+        context_window_limit: 200000,
+        context_utilisation_percent: 0.25,
+        potential_cache_hits: 0,
+        potential_cache_savings_tokens: 0,
       };
 
       stats.set(newStats);
@@ -74,7 +102,8 @@ describe("stats store", () => {
       expect(currentStats.total_input_tokens).toBe(1000);
       expect(currentStats.total_output_tokens).toBe(2000);
       expect(currentStats.model).toBe("claude-sonnet-4");
-      expect(currentStats.tools_usage).toEqual({ Read: 5, Edit: 3 });
+      expect(currentStats.tools_usage.Read?.call_count).toBe(5);
+      expect(currentStats.tools_usage.Edit?.call_count).toBe(3);
     });
 
     it("can be updated with update function", () => {
@@ -109,9 +138,14 @@ describe("stats store", () => {
         session_files_edited: 2,
         files_created: 1,
         session_files_created: 1,
-        tools_usage: { Read: 5, Edit: 3 },
+        tools_usage: { Read: toolStats(5), Edit: toolStats(3) },
-        session_tools_usage: { Read: 2, Edit: 1 },
+        session_tools_usage: { Read: toolStats(2), Edit: toolStats(1) },
         session_duration_seconds: 300,
+        context_tokens_used: 500,
+        context_window_limit: 200000,
+        context_utilisation_percent: 0.25,
+        potential_cache_hits: 0,
+        potential_cache_savings_tokens: 0,
       });
 
       // Reset session stats
@@ -127,7 +161,8 @@ describe("stats store", () => {
       expect(currentStats.code_blocks_generated).toBe(3);
       expect(currentStats.files_edited).toBe(5);
       expect(currentStats.files_created).toBe(1);
-      expect(currentStats.tools_usage).toEqual({ Read: 5, Edit: 3 });
+      expect(currentStats.tools_usage.Read?.call_count).toBe(5);
+      expect(currentStats.tools_usage.Edit?.call_count).toBe(3);
       expect(currentStats.model).toBe("claude-sonnet-4");
 
       // Session stats should be reset
@@ -277,8 +312,8 @@ describe("stats store", () => {
     });
 
     it("exposes tools usage directly", () => {
-      const toolsUsage = { Read: 10, Edit: 5, Write: 3 };
+      const toolsUsage = { Read: toolStats(10), Edit: toolStats(5), Write: toolStats(3) };
-      const sessionToolsUsage = { Read: 2, Edit: 1 };
+      const sessionToolsUsage = { Read: toolStats(2), Edit: toolStats(1) };
 
       stats.update((current) => ({
         ...current,
@@ -331,9 +366,14 @@ describe("stats store", () => {
         session_files_edited: 1,
         files_created: 1,
         session_files_created: 0,
-        tools_usage: { Read: 3 },
+        tools_usage: { Read: toolStats(3) },
-        session_tools_usage: { Read: 1 },
+        session_tools_usage: { Read: toolStats(1) },
         session_duration_seconds: 60,
+        context_tokens_used: 50,
+        context_window_limit: 200000,
+        context_utilisation_percent: 0.025,
+        potential_cache_hits: 0,
+        potential_cache_savings_tokens: 0,
       };
 
       stats.set(fullStats);
@@ -343,4 +383,221 @@ describe("stats store", () => {
       expect(currentStats).toEqual(fullStats);
     });
   });
+
+  describe("context window tracking", () => {
+    it("tracks context tokens used", () => {
+      stats.update((current) => ({
+        ...current,
+        context_tokens_used: 100000,
+        context_window_limit: 200000,
+        context_utilisation_percent: 50.0,
+      }));
+
+      const currentStats = get(stats);
+      expect(currentStats.context_tokens_used).toBe(100000);
+      expect(currentStats.context_window_limit).toBe(200000);
+      expect(currentStats.context_utilisation_percent).toBe(50.0);
+    });
+
+    it("formats context stats correctly", () => {
+      stats.update((current) => ({
+        ...current,
+        context_tokens_used: 150000,
+        context_window_limit: 200000,
+        context_utilisation_percent: 75.5,
+      }));
+
+      const formatted = get(formattedStats);
+      expect(formatted.contextUsed).toBe("150,000");
+      expect(formatted.contextLimit).toBe("200,000");
+      expect(formatted.contextRemaining).toBe("50,000");
+      expect(formatted.contextUtilisation).toBe("75.5%");
+    });
+
+    it("calculates remaining tokens correctly at limit", () => {
+      stats.update((current) => ({
+        ...current,
+        context_tokens_used: 200000,
+        context_window_limit: 200000,
+        context_utilisation_percent: 100.0,
+      }));
+
+      const formatted = get(formattedStats);
+      expect(formatted.contextRemaining).toBe("0");
+    });
+
+    it("handles over-limit gracefully", () => {
+      stats.update((current) => ({
+        ...current,
+        context_tokens_used: 250000,
+        context_window_limit: 200000,
+        context_utilisation_percent: 125.0,
+      }));
+
+      const formatted = get(formattedStats);
+      expect(formatted.contextRemaining).toBe("0");
+    });
+  });
+
+  describe("contextWarning derived store", () => {
+    it("returns null when under 50%", () => {
+      stats.update((current) => ({
+        ...current,
+        context_utilisation_percent: 40.0,
+      }));
+
+      const warning = get(contextWarning);
+      expect(warning).toBeNull();
+    });
+
+    it("returns moderate when between 50-74%", () => {
+      stats.update((current) => ({
+        ...current,
+        context_utilisation_percent: 60.0,
+      }));
+
+      const warning = get(contextWarning);
+      expect(warning).toBe("moderate");
+    });
+
+    it("returns high when between 75-89%", () => {
+      stats.update((current) => ({
+        ...current,
+        context_utilisation_percent: 80.0,
+      }));
+
+      const warning = get(contextWarning);
+      expect(warning).toBe("high");
+    });
+
+    it("returns critical when 90%+", () => {
+      stats.update((current) => ({
+        ...current,
+        context_utilisation_percent: 95.0,
+      }));
+
+      const warning = get(contextWarning);
+      expect(warning).toBe("critical");
+    });
+  });
+
+  describe("getContextWarningMessage", () => {
+    it("returns correct message for moderate warning", () => {
+      const message = getContextWarningMessage("moderate");
+      expect(message).toContain("50%+");
+      expect(message).toContain("Consider starting a new conversation");
+    });
+
+    it("returns correct message for high warning", () => {
+      const message = getContextWarningMessage("high");
+      expect(message).toContain("75%+");
+      expect(message).toContain("Responses may degrade");
+    });
+
+    it("returns correct message for critical warning", () => {
+      const message = getContextWarningMessage("critical");
+      expect(message).toContain("90%+");
+      expect(message).toContain("Start a new conversation");
+    });
+  });
+
+  describe("formatTokenCount", () => {
+    it("formats small numbers directly", () => {
+      expect(formatTokenCount(0)).toBe("0");
+      expect(formatTokenCount(100)).toBe("100");
+      expect(formatTokenCount(999)).toBe("999");
+    });
+
+    it("formats thousands with K suffix", () => {
+      expect(formatTokenCount(1000)).toBe("1.0K");
+      expect(formatTokenCount(1500)).toBe("1.5K");
+      expect(formatTokenCount(10000)).toBe("10.0K");
+      expect(formatTokenCount(999999)).toBe("1000.0K");
+    });
+
+    it("formats millions with M suffix", () => {
+      expect(formatTokenCount(1000000)).toBe("1.0M");
+      expect(formatTokenCount(1500000)).toBe("1.5M");
+      expect(formatTokenCount(10000000)).toBe("10.0M");
+    });
+  });
+
+  describe("estimateMessageCost", () => {
+    it("estimates tokens at ~4 chars per token", () => {
+      const result = estimateMessageCost("test", 0, null); // 4 chars = 1 token
+      expect(result.messageTokens).toBe(1);
+    });
+
+    it("rounds up partial tokens", () => {
+      const result = estimateMessageCost("a", 0, null); // 1 char rounds up to 1 token
+      expect(result.messageTokens).toBe(1);
+
+      const result2 = estimateMessageCost("abcde", 0, null); // 5 chars = 2 tokens
+      expect(result2.messageTokens).toBe(2);
+    });
+
+    it("returns 0 tokens for empty string", () => {
+      const result = estimateMessageCost("", 0, null);
+      expect(result.messageTokens).toBe(0);
+      expect(result.estimatedCost).toBe(0);
+    });
+
+    it("adds context tokens to total", () => {
+      const result = estimateMessageCost("test", 1000, null); // 1 token + 1000 context
+      expect(result.messageTokens).toBe(1);
+      expect(result.totalInputTokens).toBe(1001);
+    });
+
+    it("calculates cost using Sonnet pricing by default", () => {
+      // 100 chars = 25 tokens, $3 per million input tokens
+      const result = estimateMessageCost("a".repeat(100), 0, null);
+      expect(result.messageTokens).toBe(25);
+      const expectedCost = (25 / 1_000_000) * 3.0;
+      expect(result.estimatedCost).toBeCloseTo(expectedCost, 8);
+    });
+
+    it("uses Opus pricing for Opus models", () => {
+      const result = estimateMessageCost("a".repeat(100), 0, "claude-opus-4-5-20251101");
+      expect(result.messageTokens).toBe(25);
+      const expectedCost = (25 / 1_000_000) * 5.0; // Opus 4.5: $5 per million input
+      expect(result.estimatedCost).toBeCloseTo(expectedCost, 8);
+    });
+
+    it("uses Haiku pricing for Haiku models", () => {
+      const result = estimateMessageCost("a".repeat(100), 0, "claude-3-5-haiku-20241022");
+      expect(result.messageTokens).toBe(25);
+      const expectedCost = (25 / 1_000_000) * 1.0; // Haiku: $1 per million
+      expect(result.estimatedCost).toBeCloseTo(expectedCost, 8);
+    });
+
+    it("falls back to Sonnet pricing for unknown models", () => {
+      const result = estimateMessageCost("a".repeat(100), 0, "unknown-model");
+      expect(result.messageTokens).toBe(25);
+      const expectedCost = (25 / 1_000_000) * 3.0; // Default Sonnet: $3 per million
+      expect(result.estimatedCost).toBeCloseTo(expectedCost, 8);
+    });
+  });
+
+  describe("MODEL_PRICING", () => {
+    it("contains expected Opus pricing", () => {
+      // Opus 4.5 has reduced pricing
+      expect(MODEL_PRICING["claude-opus-4-5-20251101"]).toEqual({ input: 5.0, output: 25.0 });
+      // Previous Opus models have higher pricing
+      expect(MODEL_PRICING["claude-opus-4-1-20250805"]).toEqual({ input: 15.0, output: 75.0 });
+      expect(MODEL_PRICING["claude-opus-4-20250514"]).toEqual({ input: 15.0, output: 75.0 });
+    });
+
+    it("contains expected Sonnet pricing", () => {
+      expect(MODEL_PRICING["claude-sonnet-4-5-20250929"]).toEqual({ input: 3.0, output: 15.0 });
+      expect(MODEL_PRICING["claude-sonnet-4-20250514"]).toEqual({ input: 3.0, output: 15.0 });
+      expect(MODEL_PRICING["claude-3-7-sonnet-20250219"]).toEqual({ input: 3.0, output: 15.0 });
+      expect(MODEL_PRICING["claude-3-5-sonnet-20241022"]).toEqual({ input: 3.0, output: 15.0 });
+    });
+
+    it("contains expected Haiku pricing", () => {
+      expect(MODEL_PRICING["claude-haiku-4-5-20251001"]).toEqual({ input: 1.0, output: 5.0 });
+      expect(MODEL_PRICING["claude-3-5-haiku-20241022"]).toEqual({ input: 1.0, output: 5.0 });
+      expect(MODEL_PRICING["claude-3-haiku-20240307"]).toEqual({ input: 0.25, output: 1.25 });
+    });
+  });
 });

src/lib/stores/stats.ts

@@ -1,6 +1,66 @@
 import { writable, derived } from "svelte/store";
 import { listen } from "@tauri-apps/api/event";
 import { invoke } from "@tauri-apps/api/core";
+import { costTrackingStore } from "./costTracking";
+
+export type ContextWarning = "moderate" | "high" | "critical";
+export type BudgetType = "token" | "cost";
+
+// Model pricing (per million tokens) - keep in sync with stats.rs
+// Source: https://platform.claude.com/docs/en/about-claude/models/overview
+export const MODEL_PRICING: Record<string, { input: number; output: number }> = {
+  // Current generation (Claude 4.5)
+  "claude-opus-4-5-20251101": { input: 5.0, output: 25.0 },
+  "claude-sonnet-4-5-20250929": { input: 3.0, output: 15.0 },
+  "claude-haiku-4-5-20251001": { input: 1.0, output: 5.0 },
+  // Previous generation (Claude 4.x)
+  "claude-opus-4-1-20250805": { input: 15.0, output: 75.0 },
+  "claude-opus-4-20250514": { input: 15.0, output: 75.0 },
+  "claude-sonnet-4-20250514": { input: 3.0, output: 15.0 },
+  // Legacy (Claude 3.x)
+  "claude-3-7-sonnet-20250219": { input: 3.0, output: 15.0 },
+  "claude-3-5-sonnet-20241022": { input: 3.0, output: 15.0 },
+  "claude-3-5-sonnet-20240620": { input: 3.0, output: 15.0 },
+  "claude-3-5-haiku-20241022": { input: 1.0, output: 5.0 },
+  "claude-3-opus-20240229": { input: 15.0, output: 75.0 },
+  "claude-3-sonnet-20240229": { input: 3.0, output: 15.0 },
+  "claude-3-haiku-20240307": { input: 0.25, output: 1.25 },
+};
+
+const DEFAULT_PRICING = { input: 3.0, output: 15.0 }; // Default to Sonnet
+
+export interface CostEstimate {
+  messageTokens: number;
+  totalInputTokens: number;
+  estimatedCost: number;
+}
+
+// Estimate cost for a message before sending
+export function estimateMessageCost(
+  messageText: string,
+  contextTokensUsed: number,
+  model: string | null
+): CostEstimate {
+  // Estimate tokens using ~4 chars per token heuristic
+  const messageTokens = Math.ceil(messageText.length / 4);
+  const totalInputTokens = contextTokensUsed + messageTokens;
+
+  const pricing = model ? (MODEL_PRICING[model] ?? DEFAULT_PRICING) : DEFAULT_PRICING;
+  const estimatedCost = (totalInputTokens / 1_000_000) * pricing.input;
+
+  return { messageTokens, totalInputTokens, estimatedCost };
+}
+export type BudgetStatus =
+  | { type: "ok" }
+  | { type: "warning"; budget_type: BudgetType; percent_used: number }
+  | { type: "exceeded"; budget_type: BudgetType };
+
+// Per-tool token usage statistics
+export interface ToolTokenStats {
+  call_count: number;
+  estimated_input_tokens: number;
+  estimated_output_tokens: number;
+}
 
 export interface UsageStats {
   total_input_tokens: number;
@@ -20,9 +80,18 @@ export interface UsageStats {
   session_files_edited: number;
   files_created: number;
   session_files_created: number;
-  tools_usage: Record<string, number>;
+  tools_usage: Record<string, ToolTokenStats>;
-  session_tools_usage: Record<string, number>;
+  session_tools_usage: Record<string, ToolTokenStats>;
   session_duration_seconds: number;
+
+  // Context window tracking
+  context_tokens_used: number;
+  context_window_limit: number;
+  context_utilisation_percent: number;
+
+  // Cache analytics (tracks potential savings from repeated tool calls)
+  potential_cache_hits: number;
+  potential_cache_savings_tokens: number;
 }
 
 // Main stats store
@@ -45,8 +114,24 @@ export const stats = writable<UsageStats>({
   tools_usage: {},
   session_tools_usage: {},
   session_duration_seconds: 0,
+  context_tokens_used: 0,
+  context_window_limit: 200000,
+  context_utilisation_percent: 0,
+  potential_cache_hits: 0,
+  potential_cache_savings_tokens: 0,
 });
 
+// Format token count with K/M suffix
+export function formatTokenCount(tokens: number): string {
+  if (tokens >= 1000000) {
+    return `${(tokens / 1000000).toFixed(1)}M`;
+  }
+  if (tokens >= 1000) {
+    return `${(tokens / 1000).toFixed(1)}K`;
+  }
+  return tokens.toString();
+}
+
 // Derived store for formatted display values
 export const formattedStats = derived(stats, ($stats) => {
   const formatNumber = (num: number) => num.toLocaleString();
@@ -65,6 +150,20 @@ export const formattedStats = derived(stats, ($stats) => {
     }
   };
 
+  // Format tool stats with token info
+  const formatToolStats = (toolStats: Record<string, ToolTokenStats>) => {
+    return Object.entries(toolStats).map(([name, stats]) => ({
+      name,
+      callCount: stats.call_count,
+      totalTokens: stats.estimated_input_tokens + stats.estimated_output_tokens,
+      formattedTokens: formatTokenCount(
+        stats.estimated_input_tokens + stats.estimated_output_tokens
+      ),
+      inputTokens: stats.estimated_input_tokens,
+      outputTokens: stats.estimated_output_tokens,
+    }));
+  };
+
   return {
     totalTokens: formatNumber($stats.total_input_tokens + $stats.total_output_tokens),
     totalInputTokens: formatNumber($stats.total_input_tokens),
@@ -88,9 +187,116 @@ export const formattedStats = derived(stats, ($stats) => {
     sessionDuration: formatDuration($stats.session_duration_seconds),
     toolsUsage: $stats.tools_usage,
     sessionToolsUsage: $stats.session_tools_usage,
+    // Formatted tool stats with token info
+    sessionToolsFormatted: formatToolStats($stats.session_tools_usage),
+    toolsFormatted: formatToolStats($stats.tools_usage),
+
+    // Context window tracking
+    contextUsed: formatNumber($stats.context_tokens_used),
+    contextLimit: formatNumber($stats.context_window_limit),
+    contextRemaining: formatNumber(
+      Math.max(0, $stats.context_window_limit - $stats.context_tokens_used)
+    ),
+    contextUtilisation: `${$stats.context_utilisation_percent.toFixed(1)}%`,
   };
 });
 
+// Derived store for context warning state
+export const contextWarning = derived(stats, ($stats): ContextWarning | null => {
+  if ($stats.context_utilisation_percent >= 90) {
+    return "critical";
+  } else if ($stats.context_utilisation_percent >= 75) {
+    return "high";
+  } else if ($stats.context_utilisation_percent >= 50) {
+    return "moderate";
+  }
+  return null;
+});
+
+// Get warning message for context utilisation
+export function getContextWarningMessage(warning: ContextWarning): string {
+  switch (warning) {
+    case "moderate":
+      return "Context window is 50%+ full. Consider starting a new conversation for better performance.";
+    case "high":
+      return "Context window is 75%+ full. Responses may degrade. Consider summarising or starting fresh.";
+    case "critical":
+      return "Context window is nearly full (90%+)! Start a new conversation to avoid errors.";
+  }
+}
+
+// Budget checking functions
+export function checkBudget(
+  stats: UsageStats,
+  budgetEnabled: boolean,
+  tokenBudget: number | null,
+  costBudget: number | null,
+  warningThreshold: number
+): BudgetStatus {
+  if (!budgetEnabled) {
+    return { type: "ok" };
+  }
+
+  const sessionTokens = stats.session_input_tokens + stats.session_output_tokens;
+
+  // Check token budget
+  if (tokenBudget !== null) {
+    if (sessionTokens >= tokenBudget) {
+      return { type: "exceeded", budget_type: "token" };
+    }
+    const percentUsed = sessionTokens / tokenBudget;
+    if (percentUsed >= warningThreshold) {
+      return { type: "warning", budget_type: "token", percent_used: percentUsed * 100 };
+    }
+  }
+
+  // Check cost budget
+  if (costBudget !== null) {
+    if (stats.session_cost_usd >= costBudget) {
+      return { type: "exceeded", budget_type: "cost" };
+    }
+    const percentUsed = stats.session_cost_usd / costBudget;
+    if (percentUsed >= warningThreshold) {
+      return { type: "warning", budget_type: "cost", percent_used: percentUsed * 100 };
+    }
+  }
+
+  return { type: "ok" };
+}
+
+// Get budget status message
+export function getBudgetStatusMessage(status: BudgetStatus): string | null {
+  if (status.type === "ok") {
+    return null;
+  }
+
+  const budgetTypeLabel = status.budget_type === "token" ? "token" : "cost";
+
+  if (status.type === "exceeded") {
+    return `Session ${budgetTypeLabel} budget exceeded! Consider starting a new session.`;
+  }
+
+  return `Approaching ${budgetTypeLabel} budget limit (${status.percent_used.toFixed(0)}% used).`;
+}
+
+// Get remaining budget values
+export function getRemainingTokenBudget(
+  stats: UsageStats,
+  tokenBudget: number | null
+): number | null {
+  if (tokenBudget === null) return null;
+  const used = stats.session_input_tokens + stats.session_output_tokens;
+  return Math.max(0, tokenBudget - used);
+}
+
+export function getRemainingCostBudget(
+  stats: UsageStats,
+  costBudget: number | null
+): number | null {
+  if (costBudget === null) return null;
+  return Math.max(0, costBudget - stats.session_cost_usd);
+}
+
 // Note: Cost calculation is now done in the Rust backend
 
 // Initialize stats listener
@@ -102,6 +308,9 @@ export async function initStatsListener() {
 
     // The backend already tracks all totals - just set the stats directly
     stats.set(newStats);
+
+    // Refresh cost tracking to check for alerts (debounced - won't spam)
+    costTrackingStore.refresh();
   });
 
   // Load initial persisted stats from backend (no bridge required)

src/lib/tauri.ts

@@ -90,6 +90,11 @@ interface OutputPayload {
   content: string;
   tool_name: string | null;
   conversation_id?: string;
+  cost?: {
+    input_tokens: number;
+    output_tokens: number;
+    cost_usd: number;
+  };
 }
 
 interface ConnectionPayload {
@@ -242,7 +247,16 @@ export async function initializeTauriListeners() {
   unlisteners.push(stateUnlisten);
 
   const outputUnlisten = await listen<OutputPayload>("claude:output", (event) => {
-    const { line_type, content, tool_name, conversation_id } = event.payload;
+    const { line_type, content, tool_name, conversation_id, cost } = event.payload;
+
+    // Convert snake_case cost to camelCase for TypeScript
+    const costData = cost
+      ? {
+          inputTokens: cost.input_tokens,
+          outputTokens: cost.output_tokens,
+          costUsd: cost.cost_usd,
+        }
+      : undefined;
 
     // Always store the output to the correct conversation
     if (conversation_id) {
@@ -250,14 +264,16 @@ export async function initializeTauriListeners() {
         conversation_id,
         line_type as "user" | "assistant" | "system" | "tool" | "error",
         content,
-        tool_name || undefined
+        tool_name || undefined,
+        costData
       );
     } else {
       // Fallback to active conversation if no conversation_id provided
       claudeStore.addLine(
         line_type as "user" | "assistant" | "system" | "tool" | "error",
         content,
-        tool_name || undefined
+        tool_name || undefined,
+        costData
       );
     }
   });

src/lib/types/editor.ts

@@ -0,0 +1,27 @@
+export interface FileEntry {
+  name: string;
+  path: string;
+  isDirectory: boolean;
+  isExpanded?: boolean;
+  children?: FileEntry[];
+  isLoading?: boolean;
+}
+
+export interface EditorTab {
+  id: string;
+  filePath: string;
+  fileName: string;
+  content: string;
+  originalContent: string;
+  isDirty: boolean;
+  language: string;
+}
+
+export interface EditorState {
+  tabs: EditorTab[];
+  activeTabId: string | null;
+  isFileBrowserOpen: boolean;
+  currentDirectory: string;
+  fileTree: FileEntry[];
+  isLoadingTree: boolean;
+}

src/lib/types/messages.ts

@@ -4,6 +4,12 @@ export interface TerminalLine {
   content: string;
   timestamp: Date;
   toolName?: string;
+  // Cost tracking for this specific message
+  cost?: {
+    inputTokens: number;
+    outputTokens: number;
+    costUsd: number;
+  };
 }
 
 export interface SystemInitMessage {

src/lib/utils/conversationUtils.test.ts

@@ -0,0 +1,188 @@
+import { describe, it, expect } from "vitest";
+import {
+  generateSummaryPrompt,
+  generateContextInjection,
+  estimateTokens,
+  createSummary,
+  shouldSuggestCompaction,
+  formatTokenCount,
+  sanitizeForJson,
+} from "./conversationUtils";
+import type { ConversationSummary } from "$lib/stores/conversations";
+
+describe("conversationUtils", () => {
+  describe("generateSummaryPrompt", () => {
+    it("generates a prompt containing the conversation content", () => {
+      const content = "User: Hello\n\nAssistant: Hi there!";
+      const prompt = generateSummaryPrompt(content);
+
+      expect(prompt).toContain(content);
+      expect(prompt).toContain("summary");
+      expect(prompt).toContain("Key topics");
+    });
+
+    it("handles empty content", () => {
+      const prompt = generateSummaryPrompt("");
+      expect(prompt).toContain("summary");
+    });
+  });
+
+  describe("generateContextInjection", () => {
+    it("creates context injection message from summary", () => {
+      const summary: ConversationSummary = {
+        generatedAt: new Date("2024-01-01"),
+        content: "We discussed building a new feature",
+        messageCount: 50,
+        tokenEstimate: 10000,
+      };
+
+      const injection = generateContextInjection(summary);
+
+      expect(injection).toContain("Previous Session Context");
+      expect(injection).toContain("We discussed building a new feature");
+      expect(injection).toContain("50 messages");
+      expect(injection).toContain("10,000 tokens");
+    });
+  });
+
+  describe("estimateTokens", () => {
+    it("estimates tokens at ~4 chars per token", () => {
+      expect(estimateTokens("")).toBe(0);
+      expect(estimateTokens("test")).toBe(1); // 4 chars = 1 token
+      expect(estimateTokens("testing")).toBe(2); // 7 chars = 2 tokens
+      expect(estimateTokens("a".repeat(100))).toBe(25); // 100 chars = 25 tokens
+    });
+
+    it("rounds up partial tokens", () => {
+      expect(estimateTokens("a")).toBe(1); // 1 char rounds up to 1 token
+      expect(estimateTokens("ab")).toBe(1); // 2 chars rounds up to 1 token
+      expect(estimateTokens("abc")).toBe(1); // 3 chars rounds up to 1 token
+      expect(estimateTokens("abcde")).toBe(2); // 5 chars rounds up to 2 tokens
+    });
+  });
+
+  describe("createSummary", () => {
+    it("creates a valid ConversationSummary object", () => {
+      const summary = createSummary("Test summary content", 25, 5000);
+
+      expect(summary.content).toBe("Test summary content");
+      expect(summary.messageCount).toBe(25);
+      expect(summary.tokenEstimate).toBe(5000);
+      expect(summary.generatedAt).toBeInstanceOf(Date);
+    });
+
+    it("sets generatedAt to current time", () => {
+      const before = new Date();
+      const summary = createSummary("content", 10, 1000);
+      const after = new Date();
+
+      expect(summary.generatedAt.getTime()).toBeGreaterThanOrEqual(before.getTime());
+      expect(summary.generatedAt.getTime()).toBeLessThanOrEqual(after.getTime());
+    });
+  });
+
+  describe("shouldSuggestCompaction", () => {
+    it("returns false when under threshold", () => {
+      expect(shouldSuggestCompaction(50000, 200000, 60)).toBe(false); // 25%
+      expect(shouldSuggestCompaction(100000, 200000, 60)).toBe(false); // 50%
+      expect(shouldSuggestCompaction(119000, 200000, 60)).toBe(false); // 59.5%
+    });
+
+    it("returns true when at or above threshold", () => {
+      expect(shouldSuggestCompaction(120000, 200000, 60)).toBe(true); // 60%
+      expect(shouldSuggestCompaction(150000, 200000, 60)).toBe(true); // 75%
+      expect(shouldSuggestCompaction(200000, 200000, 60)).toBe(true); // 100%
+    });
+
+    it("handles zero context window limit", () => {
+      expect(shouldSuggestCompaction(50000, 0, 60)).toBe(false);
+    });
+
+    it("uses default threshold of 60%", () => {
+      expect(shouldSuggestCompaction(110000, 200000)).toBe(false); // 55%
+      expect(shouldSuggestCompaction(130000, 200000)).toBe(true); // 65%
+    });
+
+    it("respects custom threshold", () => {
+      expect(shouldSuggestCompaction(70000, 200000, 40)).toBe(false); // 35%
+      expect(shouldSuggestCompaction(90000, 200000, 40)).toBe(true); // 45%
+    });
+  });
+
+  describe("formatTokenCount", () => {
+    it("formats small numbers directly", () => {
+      expect(formatTokenCount(0)).toBe("0");
+      expect(formatTokenCount(100)).toBe("100");
+      expect(formatTokenCount(999)).toBe("999");
+    });
+
+    it("formats thousands with K suffix", () => {
+      expect(formatTokenCount(1000)).toBe("1.0K");
+      expect(formatTokenCount(1500)).toBe("1.5K");
+      expect(formatTokenCount(10000)).toBe("10.0K");
+      expect(formatTokenCount(999999)).toBe("1000.0K");
+    });
+
+    it("formats millions with M suffix", () => {
+      expect(formatTokenCount(1000000)).toBe("1.0M");
+      expect(formatTokenCount(1500000)).toBe("1.5M");
+      expect(formatTokenCount(10000000)).toBe("10.0M");
+    });
+  });
+
+  describe("sanitizeForJson", () => {
+    it("returns normal text unchanged", () => {
+      expect(sanitizeForJson("Hello world")).toBe("Hello world");
+      expect(sanitizeForJson("Test 123")).toBe("Test 123");
+    });
+
+    it("preserves common whitespace", () => {
+      expect(sanitizeForJson("line1\nline2")).toBe("line1\nline2");
+      expect(sanitizeForJson("col1\tcol2")).toBe("col1\tcol2");
+      expect(sanitizeForJson("line\r\nend")).toBe("line\r\nend");
+    });
+
+    it("removes null bytes", () => {
+      expect(sanitizeForJson("hello\x00world")).toBe("helloworld");
+    });
+
+    it("removes other control characters", () => {
+      // Bell character
+      expect(sanitizeForJson("alert\x07here")).toBe("alerthere");
+      // Backspace
+      expect(sanitizeForJson("back\x08space")).toBe("backspace");
+      // Form feed is removed
+      expect(sanitizeForJson("page\x0Cbreak")).toBe("pagebreak");
+      // Escape character
+      expect(sanitizeForJson("esc\x1Bhere")).toBe("eschere");
+    });
+
+    it("preserves printable characters including backslashes", () => {
+      const codeContent = '```rust\nfn main() {\n    println!("Hello");\n}\n```';
+      expect(sanitizeForJson(codeContent)).toBe(codeContent);
+    });
+
+    it("handles mixed content with various characters", () => {
+      const mixed = "User: Hello\n\nAssistant: Here's some code:\n```\nconst x = 42;\n```";
+      expect(sanitizeForJson(mixed)).toBe(mixed);
+    });
+
+    it("preserves backslash sequences", () => {
+      // Backslashes followed by letters should be preserved as-is
+      expect(sanitizeForJson("path\\to\\file")).toBe("path\\to\\file");
+      expect(sanitizeForJson("color\\x1b")).toBe("color\\x1b");
+    });
+
+    it("removes lone surrogates", () => {
+      // Lone surrogates (U+D800-U+DFFF) can cause JSON parse errors
+      // High surrogate without low
+      expect(sanitizeForJson("test\uD800end")).toBe("testend");
+      // Low surrogate without high
+      expect(sanitizeForJson("test\uDC00end")).toBe("testend");
+      // But valid surrogate pairs should remain (they form valid characters)
+      // Actually, JavaScript represents emoji as surrogate pairs, so this is tricky
+      // The regex will remove the surrogates, which may break emoji. That's acceptable
+      // for a conversation summary where data integrity is more important.
+    });
+  });
+});

src/lib/utils/conversationUtils.ts

@@ -0,0 +1,110 @@
+import type { ConversationSummary } from "$lib/stores/conversations";
+
+/**
+ * Sanitises a string for safe JSON serialization through Tauri IPC.
+ * Removes control characters and lone surrogates that could cause issues
+ * during JSON serialization/deserialization.
+ */
+export function sanitizeForJson(text: string): string {
+  // Remove control characters except for common whitespace (tab, newline, carriage return)
+  // These can cause JSON parsing issues and are rarely meaningful in conversation summaries.
+  // eslint-disable-next-line no-control-regex -- regex uses control character codes
+  let sanitized = text.replace(/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/g, "");
+
+  // Remove extended ASCII control chars (C1 control codes)
+  sanitized = sanitized.replace(/[\x80-\x9F]/g, "");
+
+  // Remove lone surrogates (U+D800 to U+DFFF) which cause "unexpected end of hex escape"
+  // errors in serde_json when they appear without proper pairing.
+  // These are invalid in JSON and can cause parse failures.
+  sanitized = sanitized.replace(/[\uD800-\uDFFF]/g, "");
+
+  return sanitized;
+}
+
+/**
+ * Generates a prompt to ask Claude to summarise a conversation.
+ * This can be sent as a user message to get a summary.
+ */
+export function generateSummaryPrompt(conversationContent: string): string {
+  return `Please provide a concise summary of our conversation so far. Focus on:
+1. Key topics discussed
+2. Important decisions or conclusions made
+3. Any ongoing tasks or context that would be helpful to remember
+4. Code changes or files that were modified
+
+Keep the summary brief but comprehensive enough to continue our work in a new session.
+
+Here is our conversation:
+
+${conversationContent}
+
+Please provide the summary now:`;
+}
+
+/**
+ * Generates a context injection message to prepend to a new conversation.
+ * This provides Claude with context from a previous session.
+ */
+export function generateContextInjection(summary: ConversationSummary): string {
+  return `[Previous Session Context]
+The following is a summary from our previous conversation (${summary.messageCount} messages, approximately ${summary.tokenEstimate.toLocaleString()} tokens):
+
+${summary.content}
+
+[End of Previous Context]
+
+Please continue from where we left off, or let me know if you need any clarification about the previous context.`;
+}
+
+/**
+ * Estimates the token count for a given string.
+ * Uses a rough approximation of ~4 characters per token.
+ */
+export function estimateTokens(text: string): number {
+  return Math.ceil(text.length / 4);
+}
+
+/**
+ * Creates a ConversationSummary object from summary content.
+ */
+export function createSummary(
+  content: string,
+  messageCount: number,
+  originalTokenEstimate: number
+): ConversationSummary {
+  return {
+    generatedAt: new Date(),
+    content,
+    messageCount,
+    tokenEstimate: originalTokenEstimate,
+  };
+}
+
+/**
+ * Determines if a conversation should be compacted based on token usage.
+ * Returns true if the conversation is using more than the threshold percentage
+ * of the context window.
+ */
+export function shouldSuggestCompaction(
+  contextTokensUsed: number,
+  contextWindowLimit: number,
+  thresholdPercent: number = 60
+): boolean {
+  if (contextWindowLimit === 0) return false;
+  const utilisationPercent = (contextTokensUsed / contextWindowLimit) * 100;
+  return utilisationPercent >= thresholdPercent;
+}
+
+/**
+ * Formats a token count for display.
+ */
+export function formatTokenCount(tokens: number): string {
+  if (tokens >= 1000000) {
+    return `${(tokens / 1000000).toFixed(1)}M`;
+  }
+  if (tokens >= 1000) {
+    return `${(tokens / 1000).toFixed(1)}K`;
+  }
+  return tokens.toString();
+}

src/routes/+layout.svelte

@@ -1,9 +1,17 @@
-<script>
+<script lang="ts">
   import "../app.css";
 
   let { children } = $props();
+
+  // Prevent the default context menu globally
+  // Individual components can show their own context menus by calling event.stopPropagation()
+  function handleContextMenu(event: MouseEvent) {
+    event.preventDefault();
+  }
 </script>
 
+<svelte:window oncontextmenu={handleContextMenu} />
+
 <div id="app">
   {@render children()}
 </div>