diff --git a/src/utils/__tests__/claude-settings.test.ts b/src/utils/__tests__/claude-settings.test.ts
index 132ad2e..27ddde7 100644
--- a/src/utils/__tests__/claude-settings.test.ts
+++ b/src/utils/__tests__/claude-settings.test.ts
@@ -1,42 +1,44 @@
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
 import {
-    afterEach,
     afterAll,
-    beforeAll,
+    afterEach,
     beforeEach,
     describe,
     expect,
-    it,
-    vi,
-    type Mock
+    it
 } from 'vitest';
 
 import {
-    getConfigPath,
-    isCustomConfigPath
-} from '../config';
+    CCSTATUSLINE_COMMANDS,
+    getClaudeSettingsPath,
+    installStatusLine,
+    isKnownCommand
+} from '../claude-settings';
+import { initConfigPath } from '../config';
 
-vi.mock('../config', () => ({
-    getConfigPath: vi.fn(() => '/default/settings.json'),
-    isCustomConfigPath: vi.fn(() => false)
-}));
+const ORIGINAL_CLAUDE_CONFIG_DIR = process.env.CLAUDE_CONFIG_DIR;
+let testClaudeConfigDir = '';
 
-const mockIsCustomConfigPath = isCustomConfigPath as Mock;
-const mockGetConfigPath = getConfigPath as Mock;
-const ORIGINAL_PLATFORM = process.platform;
-
-function setProcessPlatform(platform: NodeJS.Platform): void {
-    Object.defineProperty(process, 'platform', {
-        value: platform,
-        configurable: true
-    });
+function readInstalledCommand(): string {
+    const settingsPath = getClaudeSettingsPath();
+    const content = fs.readFileSync(settingsPath, 'utf-8');
+    const data = JSON.parse(content) as { statusLine?: { command?: string } };
+    return data.statusLine?.command ?? '';
 }
 
-// Safety net: point CLAUDE_CONFIG_DIR at a temp path so even if the fs mock
-// leaks, writes will never land in the user's real ~/.claude directory.
-const ORIGINAL_CLAUDE_CONFIG_DIR = process.env.CLAUDE_CONFIG_DIR;
+beforeEach(() => {
+    testClaudeConfigDir = fs.mkdtempSync(path.join(os.tmpdir(), 'ccstatusline-claude-settings-'));
+    process.env.CLAUDE_CONFIG_DIR = testClaudeConfigDir;
+    initConfigPath();
+});
 
-beforeAll(() => {
-    process.env.CLAUDE_CONFIG_DIR = '/tmp/ccstatusline-test-fake-claude-config';
+afterEach(() => {
+    initConfigPath();
+    if (testClaudeConfigDir) {
+        fs.rmSync(testClaudeConfigDir, { recursive: true, force: true });
+    }
 });
 
 afterAll(() => {
@@ -47,25 +49,6 @@ afterAll(() => {
     }
 });
 
-// Capture settings written by installStatusLine via the mock writeFile callback.
-let savedSettings: Record<string, unknown> = {};
-
-vi.mock('fs', () => ({
-    existsSync: vi.fn(() => false),
-    statSync: vi.fn(),
-    promises: {
-        readFile: vi.fn(() => Promise.resolve('{}')),
-        writeFile: vi.fn((_path: string, content: string) => {
-            savedSettings = JSON.parse(content) as Record<string, unknown>;
-            return Promise.resolve(undefined);
-        }),
-        mkdir: vi.fn(() => Promise.resolve(undefined))
-    }
-}));
-
-// Dynamic import so the module picks up the mocked fs references.
-const { CCSTATUSLINE_COMMANDS, isKnownCommand, installStatusLine } = await import('../claude-settings');
-
 describe('isKnownCommand', () => {
     it('should match exact NPM command', () => {
         expect(isKnownCommand(CCSTATUSLINE_COMMANDS.NPM)).toBe(true);
@@ -113,77 +96,39 @@ describe('isKnownCommand', () => {
 });
 
 describe('buildCommand via installStatusLine', () => {
-    beforeEach(() => {
-        savedSettings = {};
-        setProcessPlatform(ORIGINAL_PLATFORM);
-        mockIsCustomConfigPath.mockReturnValue(false);
-        mockGetConfigPath.mockReturnValue('/default/settings.json');
-    });
-
-    afterEach(() => {
-        setProcessPlatform(ORIGINAL_PLATFORM);
-    });
-
     it('should use base command when no custom config path', async () => {
-        mockIsCustomConfigPath.mockReturnValue(false);
+        initConfigPath();
         await installStatusLine(false);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(CCSTATUSLINE_COMMANDS.NPM);
+        expect(readInstalledCommand()).toBe(CCSTATUSLINE_COMMANDS.NPM);
     });
 
     it('should append --config with simple path (no quoting needed)', async () => {
-        mockIsCustomConfigPath.mockReturnValue(true);
-        mockGetConfigPath.mockReturnValue('/tmp/settings.json');
+        initConfigPath('/tmp/settings.json');
         await installStatusLine(false);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config /tmp/settings.json`);
+        expect(readInstalledCommand()).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config /tmp/settings.json`);
     });
 
     it('should quote path with spaces', async () => {
-        mockIsCustomConfigPath.mockReturnValue(true);
-        mockGetConfigPath.mockReturnValue('/my path/settings.json');
+        initConfigPath('/my path/settings.json');
         await installStatusLine(false);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config '/my path/settings.json'`);
+        expect(readInstalledCommand()).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config '/my path/settings.json'`);
     });
 
     it('should quote path with parentheses', async () => {
-        mockIsCustomConfigPath.mockReturnValue(true);
-        mockGetConfigPath.mockReturnValue('/my(path)/settings.json');
+        initConfigPath('/my(path)/settings.json');
         await installStatusLine(false);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config '/my(path)/settings.json'`);
+        expect(readInstalledCommand()).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config '/my(path)/settings.json'`);
     });
 
     it('should escape embedded single quotes in path', async () => {
-        mockIsCustomConfigPath.mockReturnValue(true);
-        mockGetConfigPath.mockReturnValue('/my\'path/settings.json');
+        initConfigPath('/my\'path/settings.json');
         await installStatusLine(false);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config '/my'\\''path/settings.json'`);
+        expect(readInstalledCommand()).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config '/my'\\''path/settings.json'`);
     });
 
     it('should use bunx command when useBunx is true', async () => {
-        mockIsCustomConfigPath.mockReturnValue(true);
-        mockGetConfigPath.mockReturnValue('/my path/settings.json');
+        initConfigPath('/my path/settings.json');
         await installStatusLine(true);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(`${CCSTATUSLINE_COMMANDS.BUNX} --config '/my path/settings.json'`);
+        expect(readInstalledCommand()).toBe(`${CCSTATUSLINE_COMMANDS.BUNX} --config '/my path/settings.json'`);
     });
-
-    it('should use Windows-safe double quoting for custom config paths', async () => {
-        setProcessPlatform('win32');
-        mockIsCustomConfigPath.mockReturnValue(true);
-        mockGetConfigPath.mockReturnValue('C:\\Users\\Alice\\My Settings\\settings.json');
-        await installStatusLine(false);
-
-        const statusLine = savedSettings.statusLine as { command: string };
-        expect(statusLine.command).toBe(`${CCSTATUSLINE_COMMANDS.NPM} --config \"C:\\Users\\Alice\\My Settings\\settings.json\"`);
-    });
-});
+});
\ No newline at end of file
diff --git a/src/utils/__tests__/config.test.ts b/src/utils/__tests__/config.test.ts
index d95f6a2..844e712 100644
--- a/src/utils/__tests__/config.test.ts
+++ b/src/utils/__tests__/config.test.ts
@@ -19,10 +19,9 @@ import {
 
 const MOCK_HOME_DIR = '/tmp/ccstatusline-config-test-home';
 
-vi.mock('os', () => ({ homedir: () => MOCK_HOME_DIR }));
-
 let loadSettings: () => Promise<Settings>;
 let saveSettings: (settings: Settings) => Promise<void>;
+let initConfigPath: (filePath?: string) => void;
 let consoleErrorSpy: ReturnType<typeof vi.spyOn>;
 
 function getSettingsPaths(): { configDir: string; settingsPath: string; backupPath: string } {
@@ -39,10 +38,13 @@ describe('config utilities', () => {
         const configModule = await import('../config');
         loadSettings = configModule.loadSettings;
         saveSettings = configModule.saveSettings;
+        initConfigPath = configModule.initConfigPath;
     });
 
     beforeEach(() => {
         fs.rmSync(MOCK_HOME_DIR, { recursive: true, force: true });
+        const { settingsPath } = getSettingsPaths();
+        initConfigPath(settingsPath);
         consoleErrorSpy = vi.spyOn(console, 'error').mockImplementation(() => undefined);
     });
 
@@ -52,6 +54,7 @@ describe('config utilities', () => {
 
     afterAll(() => {
         fs.rmSync(MOCK_HOME_DIR, { recursive: true, force: true });
+        initConfigPath();
     });
 
     it('writes defaults when settings file does not exist', async () => {
diff --git a/src/utils/claude-settings.ts b/src/utils/claude-settings.ts
index 8969913..76bfb30 100644
--- a/src/utils/claude-settings.ts
+++ b/src/utils/claude-settings.ts
@@ -168,4 +168,4 @@ export async function uninstallStatusLine(): Promise<void> {
 export async function getExistingStatusLine(): Promise<string | null> {
     const settings = await loadClaudeSettings();
     return settings.statusLine?.command ?? null;
-}
+}
\ No newline at end of file
diff --git a/src/utils/colors.ts b/src/utils/colors.ts
index 643f22b..7e1fa5a 100644
--- a/src/utils/colors.ts
+++ b/src/utils/colors.ts
@@ -446,4 +446,4 @@ export function getPowerlineTheme(name: string): PowerlineTheme | undefined {
 
 export function getDefaultPowerlineTheme(): string {
     return 'nord-aurora';
-}
+}
\ No newline at end of file
diff --git a/src/utils/config.ts b/src/utils/config.ts
index 6605545..4ff139f 100644
--- a/src/utils/config.ts
+++ b/src/utils/config.ts
@@ -158,4 +158,4 @@ export async function saveSettings(settings: Settings): Promise<void> {
     };
 
     await writeSettingsJson(settingsWithVersion, paths);
-}
+}
\ No newline at end of file