diff --git a/check-all.sh b/check-all.sh
index dc1ca4f..d05a9a0 100755
--- a/check-all.sh
+++ b/check-all.sh
@@ -36,11 +36,11 @@ echo -e "${YELLOW}🔍 Running all checks for Hikari Desktop...${NC}"
 run_check "Frontend lint" "pnpm lint" || failed=1
 run_check "Frontend format check" "pnpm format:check" || failed=1
 run_check "Frontend type check" "pnpm check" || failed=1
-run_check "Frontend tests" "pnpm test" || failed=1
+run_check "Frontend tests with coverage" "pnpm test:coverage" || failed=1
 
 # Backend checks
-run_check "Backend clippy (strict)" "cd src-tauri && cargo clippy --all-targets --all-features -- -D warnings" || failed=1
-run_check "Backend tests" "cargo test" || failed=1
+run_check "Backend clippy (strict)" "(cd src-tauri && cargo clippy --all-targets --all-features -- -D warnings)" || failed=1
+run_check "Backend tests with coverage" "(cd src-tauri && cargo llvm-cov --fail-under-lines 50)" || failed=1
 
 # Summary
 echo -e "\n${YELLOW}========================================${NC}"
diff --git a/src/lib/stores/config.test.ts b/src/lib/stores/config.test.ts
index 8abcbd7..40db753 100644
--- a/src/lib/stores/config.test.ts
+++ b/src/lib/stores/config.test.ts
@@ -14,6 +14,7 @@ import {
   type Theme,
   type CustomThemeColors,
 } from "./config";
+import { invoke } from "@tauri-apps/api/core";
 
 // Mock Tauri APIs
 vi.mock("@tauri-apps/api/core", () => ({
@@ -487,4 +488,329 @@ describe("config store", () => {
       expect(typeof configStore.saveError.subscribe).toBe("function");
     });
   });
+
+  describe("Race Condition Tests", () => {
+    beforeEach(async () => {
+      // Setup mock to return a default config for load_config
+      const mockInvokeImpl = vi.mocked(invoke);
+      mockInvokeImpl.mockResolvedValue({
+        model: null,
+        api_key: null,
+        custom_instructions: null,
+        mcp_servers_json: null,
+        auto_granted_tools: [],
+        theme: "dark",
+        greeting_enabled: false,
+        greeting_custom_prompt: null,
+        notifications_enabled: false,
+        notification_volume: 0.7,
+        always_on_top: false,
+        update_checks_enabled: false,
+        character_panel_width: null,
+        font_size: 14,
+        streamer_mode: false,
+        streamer_hide_paths: false,
+        compact_mode: false,
+        profile_name: null,
+        profile_avatar_path: null,
+        profile_bio: null,
+        custom_theme_colors: {
+          bg_primary: null,
+          bg_secondary: null,
+          bg_terminal: null,
+          accent_primary: null,
+          accent_secondary: null,
+          text_primary: null,
+          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,
+        discord_rpc_enabled: false,
+      });
+
+      // Load initial config
+      await configStore.loadConfig();
+      vi.clearAllMocks();
+    });
+
+    it("handles rapid sequential config updates correctly", async () => {
+      // This test validates the fix for the config race condition that caused data loss
+      const mockInvokeImpl = vi.mocked(invoke);
+      const invokeCalls: Array<{ command: string; config: HikariConfig }> = [];
+
+      mockInvokeImpl.mockImplementation(async (command: string, args?: unknown) => {
+        if (command === "save_config" && args && typeof args === "object" && "config" in args) {
+          invokeCalls.push({ command, config: args.config as HikariConfig });
+          // Simulate small delay in saving
+          await new Promise((resolve) => setTimeout(resolve, 10));
+        }
+        return null;
+      });
+
+      // Perform rapid updates
+      await Promise.all([
+        configStore.updateConfig({ font_size: 16 }),
+        configStore.updateConfig({ theme: "light" }),
+        configStore.updateConfig({ compact_mode: true }),
+      ]);
+
+      // All three updates should have been saved
+      expect(invokeCalls.length).toBe(3);
+
+      // Get final config
+      const finalConfig = configStore.getConfig();
+
+      // Final config should have all updates
+      // Note: The last update wins for each field, but all fields should be preserved
+      expect(finalConfig.compact_mode).toBe(true);
+    });
+
+    it("preserves previous field values during concurrent updates", async () => {
+      // Set initial values
+      await configStore.updateConfig({
+        font_size: 16,
+        theme: "dark",
+        compact_mode: false,
+        streamer_mode: false,
+      });
+
+      vi.clearAllMocks();
+
+      const mockInvokeImpl = vi.mocked(invoke);
+      const invokeCalls: Array<{ command: string; config: HikariConfig }> = [];
+
+      mockInvokeImpl.mockImplementation(async (command: string, args?: unknown) => {
+        if (command === "save_config" && args && typeof args === "object" && "config" in args) {
+          invokeCalls.push({ command, config: args.config as HikariConfig });
+          await new Promise((resolve) => setTimeout(resolve, 5));
+        }
+        return null;
+      });
+
+      // Update different fields concurrently
+      await Promise.all([
+        configStore.updateConfig({ font_size: 18 }),
+        configStore.updateConfig({ theme: "light" }),
+        configStore.updateConfig({ compact_mode: true }),
+      ]);
+
+      // Check that each save included all previous config values
+      invokeCalls.forEach((call) => {
+        // Each save should have a complete config, not just the updated field
+        expect(call.config).toHaveProperty("font_size");
+        expect(call.config).toHaveProperty("theme");
+        expect(call.config).toHaveProperty("compact_mode");
+        expect(call.config).toHaveProperty("streamer_mode");
+        expect(call.config).toHaveProperty("model");
+        expect(call.config).toHaveProperty("api_key");
+      });
+    });
+
+    it("handles update during save operation", async () => {
+      const mockInvokeImpl = vi.mocked(invoke);
+      let firstSaveStarted = false;
+      let firstSaveCompleted = false;
+
+      mockInvokeImpl.mockImplementation(async (command: string) => {
+        if (command === "save_config") {
+          if (!firstSaveStarted) {
+            firstSaveStarted = true;
+            // Simulate slow save
+            await new Promise((resolve) => setTimeout(resolve, 50));
+            firstSaveCompleted = true;
+          } else {
+            // Second save starts while first is in progress
+            expect(firstSaveStarted).toBe(true);
+            // First save might not be complete yet (race condition scenario)
+          }
+        }
+        return null;
+      });
+
+      // Start first update
+      const firstUpdate = configStore.updateConfig({ font_size: 16 });
+
+      // Wait a bit then start second update whilst first is still saving
+      await new Promise((resolve) => setTimeout(resolve, 10));
+      const secondUpdate = configStore.updateConfig({ theme: "light" });
+
+      // Wait for both to complete
+      await Promise.all([firstUpdate, secondUpdate]);
+
+      // Both should complete successfully without errors
+      expect(firstSaveCompleted).toBe(true);
+    });
+
+    it("getConfig returns most recently set configuration", async () => {
+      await configStore.updateConfig({ font_size: 14 });
+      expect(configStore.getConfig().font_size).toBe(14);
+
+      await configStore.updateConfig({ font_size: 16 });
+      expect(configStore.getConfig().font_size).toBe(16);
+
+      await configStore.updateConfig({ font_size: 18 });
+      expect(configStore.getConfig().font_size).toBe(18);
+    });
+
+    it("updates do not lose data from previous operations", async () => {
+      // Set multiple fields
+      await configStore.updateConfig({
+        font_size: 16,
+        theme: "dark",
+        compact_mode: true,
+        streamer_mode: true,
+        model: "claude-sonnet-4",
+      });
+
+      // Update just one field
+      await configStore.updateConfig({ theme: "light" });
+
+      // Other fields should be preserved
+      const config = configStore.getConfig();
+      expect(config.theme).toBe("light");
+      expect(config.font_size).toBe(16);
+      expect(config.compact_mode).toBe(true);
+      expect(config.streamer_mode).toBe(true);
+      expect(config.model).toBe("claude-sonnet-4");
+    });
+
+    it("auto granted tools are not lost during other updates", async () => {
+      // Add some tools
+      await configStore.addAutoGrantedTool("Read");
+      await configStore.addAutoGrantedTool("Write");
+
+      expect(configStore.getConfig().auto_granted_tools).toContain("Read");
+      expect(configStore.getConfig().auto_granted_tools).toContain("Write");
+
+      // Update another field
+      await configStore.updateConfig({ theme: "light" });
+
+      // Tools should still be there
+      expect(configStore.getConfig().auto_granted_tools).toContain("Read");
+      expect(configStore.getConfig().auto_granted_tools).toContain("Write");
+    });
+
+    it("custom theme colors persist across other config updates", async () => {
+      const customColors: CustomThemeColors = {
+        bg_primary: "#1a1a2e",
+        bg_secondary: "#16213e",
+        bg_terminal: "#0f0f23",
+        accent_primary: "#e94560",
+        accent_secondary: "#533483",
+        text_primary: "#eaeaea",
+        text_secondary: "#a0a0a0",
+        border_color: "#333355",
+      };
+
+      await configStore.setCustomThemeColors(customColors);
+
+      // Update another field
+      await configStore.updateConfig({ font_size: 18 });
+
+      // Colors should still be there
+      const config = configStore.getConfig();
+      expect(config.custom_theme_colors.bg_primary).toBe("#1a1a2e");
+      expect(config.custom_theme_colors.accent_primary).toBe("#e94560");
+    });
+
+    it("handles save errors gracefully without losing data", async () => {
+      const mockInvokeImpl = vi.mocked(invoke);
+
+      // Set initial config
+      await configStore.updateConfig({ font_size: 14 });
+
+      // Make next save fail
+      mockInvokeImpl.mockRejectedValueOnce(new Error("Save failed"));
+
+      // Try to update - should throw
+      await expect(configStore.updateConfig({ theme: "light" })).rejects.toThrow();
+
+      // Original config should still be accessible
+      expect(configStore.getConfig().font_size).toBe(14);
+    });
+  });
+
+  describe("Config Persistence Tests", () => {
+    it("loadConfig retrieves saved configuration", async () => {
+      const mockConfig: HikariConfig = {
+        model: "claude-sonnet-4",
+        api_key: "test-key",
+        custom_instructions: "Be helpful",
+        mcp_servers_json: "{}",
+        auto_granted_tools: ["Read", "Write"],
+        theme: "light",
+        greeting_enabled: false,
+        greeting_custom_prompt: null,
+        notifications_enabled: false,
+        notification_volume: 0.5,
+        always_on_top: true,
+        update_checks_enabled: false,
+        character_panel_width: 400,
+        font_size: 18,
+        streamer_mode: true,
+        streamer_hide_paths: true,
+        compact_mode: true,
+        profile_name: "Test User",
+        profile_avatar_path: "/test/avatar.png",
+        profile_bio: "Test bio",
+        custom_theme_colors: {
+          bg_primary: null,
+          bg_secondary: null,
+          bg_terminal: null,
+          accent_primary: null,
+          accent_secondary: null,
+          text_primary: null,
+          text_secondary: null,
+          border_color: null,
+        },
+        budget_enabled: true,
+        session_token_budget: 100000,
+        session_cost_budget: 1.5,
+        budget_action: "block",
+        budget_warning_threshold: 0.9,
+        discord_rpc_enabled: false,
+      };
+
+      const mockInvokeImpl = vi.mocked(invoke);
+      mockInvokeImpl.mockResolvedValueOnce(mockConfig);
+
+      await configStore.loadConfig();
+
+      const loadedConfig = configStore.getConfig();
+      expect(loadedConfig.model).toBe("claude-sonnet-4");
+      expect(loadedConfig.theme).toBe("light");
+      expect(loadedConfig.font_size).toBe(18);
+      expect(loadedConfig.auto_granted_tools).toEqual(["Read", "Write"]);
+    });
+
+    it("saveConfig persists configuration to backend", async () => {
+      const mockInvokeImpl = vi.mocked(invoke);
+      const savedConfigs: HikariConfig[] = [];
+
+      mockInvokeImpl.mockImplementation(async (command: string, args?: unknown) => {
+        if (command === "save_config" && args && typeof args === "object" && "config" in args) {
+          savedConfigs.push(args.config as HikariConfig);
+        }
+        return null;
+      });
+
+      const configToSave: Partial<HikariConfig> = {
+        model: "claude-sonnet-4",
+        theme: "dark",
+        font_size: 16,
+      };
+
+      await configStore.updateConfig(configToSave);
+
+      expect(savedConfigs.length).toBeGreaterThan(0);
+      const lastSaved = savedConfigs[savedConfigs.length - 1];
+      expect(lastSaved.model).toBe("claude-sonnet-4");
+      expect(lastSaved.theme).toBe("dark");
+      expect(lastSaved.font_size).toBe(16);
+    });
+  });
 });