diff --git a/src/lib/stores/clipboard.test.ts b/src/lib/stores/clipboard.test.ts
index 167650f..1671a97 100644
--- a/src/lib/stores/clipboard.test.ts
+++ b/src/lib/stores/clipboard.test.ts
@@ -552,6 +552,48 @@ describe("clipboardStore - store actions", () => {
       expect(consoleErrorSpy).toHaveBeenCalledWith("Failed to toggle pin:", expect.any(Error));
       consoleErrorSpy.mockRestore();
     });
+
+    it("exercises the unpinned-before-pinned sort branch", async () => {
+      // Three entries so sort compares (entry-1 unpinned, entry-2 pinned) — hits line 144
+      const e1 = { ...mockEntry, id: "e1", is_pinned: false };
+      const e2 = { ...mockEntry, id: "e2", is_pinned: false };
+      const e3 = { ...mockEntry, id: "e3", is_pinned: false };
+      clipboardStore.entries.set([e1, e2, e3]);
+      const pinned = { ...e2, is_pinned: true };
+      setMockInvokeResult("toggle_pin_clipboard_entry", pinned);
+      await clipboardStore.togglePin("e2");
+      expect(get(clipboardStore.entries)[0].id).toBe("e2");
+    });
+
+    it("sorts same-pin-status entries by timestamp descending", async () => {
+      // Toggle entry to pinned while two others remain unpinned — sort compares unpinned pair by timestamp
+      const older = {
+        ...mockEntry,
+        id: "older",
+        is_pinned: false,
+        timestamp: "2026-01-01T00:00:00.000Z",
+      };
+      const newer = {
+        ...mockEntry,
+        id: "newer",
+        is_pinned: false,
+        timestamp: "2026-01-02T00:00:00.000Z",
+      };
+      const pinned = {
+        ...mockEntry,
+        id: "pinned",
+        is_pinned: false,
+        timestamp: "2026-01-03T00:00:00.000Z",
+      };
+      clipboardStore.entries.set([older, newer, pinned]);
+      const pinnedResult = { ...pinned, is_pinned: true };
+      setMockInvokeResult("toggle_pin_clipboard_entry", pinnedResult);
+      await clipboardStore.togglePin("pinned");
+      const entries = get(clipboardStore.entries);
+      expect(entries[0].id).toBe("pinned");
+      expect(entries[1].id).toBe("newer");
+      expect(entries[2].id).toBe("older");
+    });
   });
 
   describe("clearHistory", () => {
@@ -587,6 +629,16 @@ describe("clipboardStore - store actions", () => {
       expect(get(clipboardStore.entries)[0].language).toBe("javascript");
     });
 
+    it("leaves non-matching entries unchanged", async () => {
+      const other = { ...mockEntry, id: "other", language: "python" };
+      clipboardStore.entries.set([mockEntry, other]);
+      const updated = { ...mockEntry, language: "javascript" };
+      setMockInvokeResult("update_clipboard_language", updated);
+      await clipboardStore.updateLanguage("entry-1", "javascript");
+      const entries = get(clipboardStore.entries);
+      expect(entries[1].language).toBe("python");
+    });
+
     it("handles errors gracefully", async () => {
       const consoleErrorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
       setMockInvokeResult("update_clipboard_language", new Error("Failed"));
diff --git a/src/lib/stores/editor.test.ts b/src/lib/stores/editor.test.ts
index 0154423..5aca84e 100644
--- a/src/lib/stores/editor.test.ts
+++ b/src/lib/stores/editor.test.ts
@@ -360,3 +360,280 @@ describe("editorStore - initializeFileTree", () => {
     consoleErrorSpy.mockRestore();
   });
 });
+
+describe("editorStore - toggleDirectory", () => {
+  beforeEach(async () => {
+    const entries = [
+      {
+        path: "/path/dir",
+        name: "dir",
+        isDirectory: true,
+        isExpanded: false,
+        children: undefined,
+      },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+  });
+
+  it("does nothing when entry is not a directory", async () => {
+    const nonDirEntry = {
+      path: "/path/file.ts",
+      name: "file.ts",
+      isDirectory: false,
+    };
+    const treeBefore = get(editorStore.fileTree);
+    await editorStore.toggleDirectory(nonDirEntry);
+    expect(get(editorStore.fileTree)).toEqual(treeBefore);
+  });
+
+  it("expands a collapsed directory and loads children asynchronously", async () => {
+    const children = [
+      { path: "/path/dir/child.ts", name: "child.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", children);
+
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+
+    const updatedEntry = get(editorStore.fileTree)[0];
+    expect(updatedEntry.isExpanded).toBe(true);
+    expect(updatedEntry.children).toEqual(children);
+    expect(updatedEntry.isLoading).toBe(false);
+  });
+
+  it("collapses an expanded directory", async () => {
+    const children = [
+      { path: "/path/dir/child.ts", name: "child.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", children);
+
+    // Expand first
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+    expect(get(editorStore.fileTree)[0].isExpanded).toBe(true);
+
+    // Now collapse
+    const expandedEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(expandedEntry);
+    expect(get(editorStore.fileTree)[0].isExpanded).toBe(false);
+  });
+
+  it("expands a directory that already has children without reloading", async () => {
+    // Re-init with a directory that already has children
+    const entries = [
+      {
+        path: "/path/dir",
+        name: "dir",
+        isDirectory: true,
+        isExpanded: false,
+        children: [
+          {
+            path: "/path/dir/child.ts",
+            name: "child.ts",
+            isDirectory: false,
+            children: undefined,
+          },
+        ],
+      },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+
+    // Toggle should expand without loading (children already present)
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+
+    const updatedEntry = get(editorStore.fileTree)[0];
+    expect(updatedEntry.isExpanded).toBe(true);
+    expect(updatedEntry.children).toHaveLength(1);
+  });
+
+  it("handles tree with multiple entries when toggling — exercises non-matching leaf fallback", async () => {
+    // Tree has dir + a sibling file; toggling dir exercises the `return e` branch for the file
+    const entries = [
+      {
+        path: "/path/dir",
+        name: "dir",
+        isDirectory: true,
+        isExpanded: false,
+        children: undefined,
+      },
+      { path: "/path/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+
+    const children: never[] = [];
+    setMockInvokeResult("list_directory", children);
+    const dirEntry = get(editorStore.fileTree)[0];
+    await editorStore.toggleDirectory(dirEntry);
+
+    // The sibling file should remain unchanged
+    expect(get(editorStore.fileTree)[1].path).toBe("/path/file.ts");
+    expect(get(editorStore.fileTree)[0].isExpanded).toBe(true);
+  });
+
+  it("handles nested directory toggle — exercises recursive updateTree branches", async () => {
+    // Tree: outer_dir → [inner_dir (no children), sibling_file]
+    // Toggling inner_dir covers the recursive path through outer's children
+    const entries = [
+      {
+        path: "/path/outer",
+        name: "outer",
+        isDirectory: true,
+        isExpanded: true,
+        children: [
+          {
+            path: "/path/outer/inner",
+            name: "inner",
+            isDirectory: true,
+            isExpanded: false,
+            children: undefined,
+          },
+          {
+            path: "/path/outer/sibling.ts",
+            name: "sibling.ts",
+            isDirectory: false,
+            children: undefined,
+          },
+        ],
+      },
+    ];
+    setMockInvokeResult("list_directory", entries);
+    await editorStore.initializeFileTree("/path");
+
+    const innerChildren = [
+      {
+        path: "/path/outer/inner/deep.ts",
+        name: "deep.ts",
+        isDirectory: false,
+        children: undefined,
+      },
+    ];
+    setMockInvokeResult("list_directory", innerChildren);
+
+    const innerEntry = get(editorStore.fileTree)[0].children![0];
+    await editorStore.toggleDirectory(innerEntry);
+
+    const outer = get(editorStore.fileTree)[0];
+    expect(outer.children![0].isExpanded).toBe(true);
+    expect(outer.children![0].children).toEqual(innerChildren);
+  });
+});
+
+describe("editorStore - deleteFile closes open tab", () => {
+  it("closes the tab when the deleted file is open", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/file.ts");
+    expect(get(editorStore.tabs)).toHaveLength(1);
+
+    setMockInvokeResult("delete_file", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.deleteFile("/path/to/file.ts");
+    expect(get(editorStore.tabs)).toHaveLength(0);
+  });
+});
+
+describe("editorStore - deleteDirectory closes open tabs", () => {
+  it("closes all tabs inside the deleted directory", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/dir/file1.ts");
+    await editorStore.openFile("/path/to/dir/nested/file2.ts");
+    await editorStore.openFile("/path/to/other.ts");
+    expect(get(editorStore.tabs)).toHaveLength(3);
+
+    setMockInvokeResult("delete_directory", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.deleteDirectory("/path/to/dir");
+
+    const remainingTabs = get(editorStore.tabs);
+    expect(remainingTabs).toHaveLength(1);
+    expect(remainingTabs[0].filePath).toBe("/path/to/other.ts");
+  });
+});
+
+describe("editorStore - renamePath updates open tabs", () => {
+  it("updates filePath and fileName when the renamed file is open in a tab", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/old-name.ts");
+
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-name.ts", "new-name.ts");
+
+    const tab = get(editorStore.activeTab);
+    expect(tab?.filePath).toBe("/path/to/new-name.ts");
+    expect(tab?.fileName).toBe("new-name.ts");
+  });
+
+  it("updates filePaths for tabs inside a renamed directory", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/old-dir/file.ts");
+
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-dir", "new-dir");
+
+    const tab = get(editorStore.activeTab);
+    expect(tab?.filePath).toBe("/path/to/new-dir/file.ts");
+  });
+
+  it("leaves unrelated tabs unchanged when renaming — exercises return-t fallback", async () => {
+    setMockInvokeResult("read_file_content", FILE_CONTENT);
+    await editorStore.openFile("/path/to/unrelated.ts");
+    await editorStore.openFile("/path/to/old-name.ts");
+
+    setMockInvokeResult("rename_path", undefined);
+    setMockInvokeResult("list_directory", []);
+    await editorStore.renamePath("/path/to/old-name.ts", "new-name.ts");
+
+    const tabs = get(editorStore.tabs);
+    const unrelated = tabs.find((t) => t.filePath === "/path/to/unrelated.ts");
+    expect(unrelated).toBeDefined();
+    expect(unrelated?.fileName).toBe("unrelated.ts");
+  });
+});
+
+describe("editorStore - refreshDirectory", () => {
+  it("reloads the entire tree when refreshing the root directory", async () => {
+    const initialEntries = [
+      { path: "/root/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", initialEntries);
+    await editorStore.initializeFileTree("/root");
+    expect(get(editorStore.fileTree)).toHaveLength(1);
+
+    const updatedEntries = [
+      { path: "/root/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+      { path: "/root/new.ts", name: "new.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", updatedEntries);
+    await editorStore.refreshDirectory("/root");
+    expect(get(editorStore.fileTree)).toHaveLength(2);
+  });
+
+  it("updates a subdirectory entry in the tree", async () => {
+    const initialEntries = [
+      {
+        path: "/root/subdir",
+        name: "subdir",
+        isDirectory: true,
+        isExpanded: true,
+        children: [],
+      },
+    ];
+    setMockInvokeResult("list_directory", initialEntries);
+    await editorStore.initializeFileTree("/root");
+
+    const subChildren = [
+      { path: "/root/subdir/file.ts", name: "file.ts", isDirectory: false, children: undefined },
+    ];
+    setMockInvokeResult("list_directory", subChildren);
+    await editorStore.refreshDirectory("/root/subdir");
+
+    const tree = get(editorStore.fileTree);
+    expect(tree[0].children).toEqual(subChildren);
+    expect(tree[0].isExpanded).toBe(true);
+  });
+});
diff --git a/src/lib/stores/sessions.test.ts b/src/lib/stores/sessions.test.ts
index 810c7e5..f686f06 100644
--- a/src/lib/stores/sessions.test.ts
+++ b/src/lib/stores/sessions.test.ts
@@ -220,6 +220,16 @@ describe("sessionsStore - scheduleAutoSave and cancelAutoSave", () => {
   it("handles cancel when no auto-save is pending", () => {
     sessionsStore.cancelAutoSave("non-existent-id");
   });
+
+  it("clears an existing pending auto-save when rescheduled for the same conversation", async () => {
+    setMockInvokeResult("save_session", undefined);
+    setMockInvokeResult("list_sessions", []);
+    const conv = makeConversation();
+    sessionsStore.scheduleAutoSave(conv as never);
+    // Schedule again before timer fires — hits clearTimeout branch (line 487)
+    sessionsStore.scheduleAutoSave(conv as never);
+    await vi.advanceTimersByTimeAsync(2001);
+  });
 });
 
 describe("sessionsStore - exportSessionAsJson", () => {
@@ -254,6 +264,17 @@ describe("sessionsStore - exportSessionAsJson", () => {
     expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(false);
     spy.mockRestore();
   });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.json");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsJson("session-1")).toBe(false);
+    spy.mockRestore();
+  });
 });
 
 describe("sessionsStore - exportSessionAsMarkdown", () => {
@@ -318,6 +339,17 @@ describe("sessionsStore - exportSessionAsMarkdown", () => {
     expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(false);
     spy.mockRestore();
   });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.md");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsMarkdown("session-1")).toBe(false);
+    spy.mockRestore();
+  });
 });
 
 describe("sessionsStore - exportSessionAsHtml (tests escapeHtml + generateHtmlExport)", () => {
@@ -424,6 +456,17 @@ describe("sessionsStore - exportSessionAsHtml (tests escapeHtml + generateHtmlEx
     expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(false);
     spy.mockRestore();
   });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session.html");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsHtml("session-1")).toBe(false);
+    spy.mockRestore();
+  });
 });
 
 describe("sessionsStore - exportSessionAsPdf (tests generatePrintableHtml)", () => {
@@ -472,6 +515,17 @@ describe("sessionsStore - exportSessionAsPdf (tests generatePrintableHtml)", ()
     expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(false);
     spy.mockRestore();
   });
+
+  it("returns false when writeTextFile throws", async () => {
+    const { save } = await import("@tauri-apps/plugin-dialog");
+    const { writeTextFile } = await import("@tauri-apps/plugin-fs");
+    const spy = vi.spyOn(console, "error").mockImplementation(() => {});
+    setMockInvokeResult("load_session", makeSavedSession());
+    vi.mocked(save).mockResolvedValue("/output/session-print.html");
+    vi.mocked(writeTextFile).mockRejectedValueOnce(new Error("Disk full"));
+    expect(await sessionsStore.exportSessionAsPdf("session-1")).toBe(false);
+    spy.mockRestore();
+  });
 });
 
 describe("sessionsStore - importSession", () => {