diff --git a/src/shared/utils/extensionNormalizers.ts b/src/shared/utils/extensionNormalizers.ts
index c466fb1d..a67943a0 100644
--- a/src/shared/utils/extensionNormalizers.ts
+++ b/src/shared/utils/extensionNormalizers.ts
@@ -125,13 +125,7 @@ export function hasInstallationInScope(
   return installations.some((installation) => installation.scope === scope);
 }
 
-/**
- * Build a concise install-status label for plugin badges.
- */
-export function getInstallationSummaryLabel(
-  installations: Pick<InstalledPluginEntry, 'scope'>[]
-): string | null {
-  const scopes = Array.from(new Set(installations.map((installation) => installation.scope)));
+function summarizeInstallationScopes(scopes: InstallScope[]): string | null {
   if (scopes.length === 0) {
     return null;
   }
@@ -152,6 +146,16 @@ export function getInstallationSummaryLabel(
   }
 }
 
+/**
+ * Build a concise install-status label for plugin badges.
+ */
+export function getInstallationSummaryLabel(
+  installations: Pick<InstalledPluginEntry, 'scope'>[]
+): string | null {
+  const scopes = Array.from(new Set(installations.map((installation) => installation.scope)));
+  return summarizeInstallationScopes(scopes);
+}
+
 const MCP_SCOPE_PRIORITY: Record<InstalledMcpEntry['scope'], number> = {
   local: 0,
   project: 1,
@@ -181,24 +185,7 @@ export function getMcpInstallationSummaryLabel(
   installations: Pick<InstalledMcpEntry, 'scope'>[]
 ): string | null {
   const scopes = Array.from(new Set(installations.map((installation) => installation.scope)));
-  if (scopes.length === 0) {
-    return null;
-  }
-
-  if (scopes.length > 1) {
-    return `Installed in ${scopes.length} scopes`;
-  }
-
-  switch (scopes[0]) {
-    case 'user':
-      return 'Installed globally';
-    case 'project':
-      return 'Installed in project';
-    case 'local':
-      return 'Installed locally';
-    default:
-      return 'Installed';
-  }
+  return summarizeInstallationScopes(scopes);
 }
 
 /**
diff --git a/test/main/services/extensions/McpInstallationStateService.test.ts b/test/main/services/extensions/McpInstallationStateService.test.ts
index 61bfb566..32d23ef6 100644
--- a/test/main/services/extensions/McpInstallationStateService.test.ts
+++ b/test/main/services/extensions/McpInstallationStateService.test.ts
@@ -1,10 +1,20 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import * as fs from 'node:fs/promises';
+import * as path from 'node:path';
 
 import { McpInstallationStateService } from '@main/services/extensions/state/McpInstallationStateService';
 
+const TEST_ROOT = path.parse(process.cwd()).root || path.sep;
+const MOCK_HOME_PATH = path.join(TEST_ROOT, 'tmp', 'mock-home');
+const PROJECT_A_PATH = path.join(TEST_ROOT, 'tmp', 'project-a');
+const PROJECT_B_PATH = path.join(TEST_ROOT, 'tmp', 'project-b');
+
+function normalizeMockPath(filePath: unknown): string {
+  return String(filePath).replaceAll('\\', '/');
+}
+
 vi.mock('@main/utils/pathDecoder', () => ({
-  getHomeDir: () => '/tmp/mock-home',
+  getHomeDir: () => MOCK_HOME_PATH,
 }));
 
 vi.mock('node:fs/promises');
@@ -25,14 +35,14 @@ describe('McpInstallationStateService', () => {
   describe('getInstalled', () => {
     it('includes local scope from the current project entry in ~/.claude.json', async () => {
       mockedFs.readFile.mockImplementation(async (filePath) => {
-        const normalizedPath = String(filePath);
-        if (normalizedPath === '/tmp/mock-home/.claude.json') {
+        const normalizedPath = normalizeMockPath(filePath);
+        if (normalizedPath === normalizeMockPath(path.join(MOCK_HOME_PATH, '.claude.json'))) {
           return JSON.stringify({
             mcpServers: {
               context7: { command: 'npx -y @upstash/context7-mcp' },
             },
             projects: {
-              '/tmp/project-a': {
+              [PROJECT_A_PATH]: {
                 mcpServers: {
                   stripe: { url: 'https://mcp.stripe.com' },
                 },
@@ -41,7 +51,7 @@ describe('McpInstallationStateService', () => {
           });
         }
 
-        if (normalizedPath === '/tmp/project-a/.mcp.json') {
+        if (normalizedPath === normalizeMockPath(path.join(PROJECT_A_PATH, '.mcp.json'))) {
           return JSON.stringify({
             mcpServers: {
               paypal: { url: 'https://mcp.paypal.com/mcp' },
@@ -52,7 +62,7 @@ describe('McpInstallationStateService', () => {
         throw Object.assign(new Error('ENOENT'), { code: 'ENOENT' });
       });
 
-      const entries = await service.getInstalled('/tmp/project-a');
+      const entries = await service.getInstalled(PROJECT_A_PATH);
 
       expect(entries).toEqual([
         { name: 'context7', scope: 'user', transport: 'stdio' },
@@ -63,8 +73,8 @@ describe('McpInstallationStateService', () => {
 
     it('caches results within TTL for the same project path', async () => {
       mockedFs.readFile.mockImplementation(async (filePath) => {
-        const normalizedPath = String(filePath);
-        if (normalizedPath === '/tmp/mock-home/.claude.json') {
+        const normalizedPath = normalizeMockPath(filePath);
+        if (normalizedPath === normalizeMockPath(path.join(MOCK_HOME_PATH, '.claude.json'))) {
           return JSON.stringify({
             mcpServers: {
               context7: { command: 'npx -y @upstash/context7-mcp' },
@@ -72,7 +82,7 @@ describe('McpInstallationStateService', () => {
           });
         }
 
-        if (normalizedPath === '/tmp/project-a/.mcp.json') {
+        if (normalizedPath === normalizeMockPath(path.join(PROJECT_A_PATH, '.mcp.json'))) {
           return JSON.stringify({
             mcpServers: {
               'repo-a-server': { url: 'https://repo-a.example.com/mcp' },
@@ -83,27 +93,27 @@ describe('McpInstallationStateService', () => {
         throw Object.assign(new Error('ENOENT'), { code: 'ENOENT' });
       });
 
-      await service.getInstalled('/tmp/project-a');
-      await service.getInstalled('/tmp/project-a');
+      await service.getInstalled(PROJECT_A_PATH);
+      await service.getInstalled(PROJECT_A_PATH);
 
       expect(mockedFs.readFile).toHaveBeenCalledTimes(2);
     });
 
     it('caches results independently per project path', async () => {
       mockedFs.readFile.mockImplementation(async (filePath) => {
-        const normalizedPath = String(filePath);
-        if (normalizedPath === '/tmp/mock-home/.claude.json') {
+        const normalizedPath = normalizeMockPath(filePath);
+        if (normalizedPath === normalizeMockPath(path.join(MOCK_HOME_PATH, '.claude.json'))) {
           return JSON.stringify({
             mcpServers: {
               context7: { command: 'npx -y @upstash/context7-mcp' },
             },
             projects: {
-              '/tmp/project-a': {
+              [PROJECT_A_PATH]: {
                 mcpServers: {
                   stripe: { url: 'https://mcp.stripe.com' },
                 },
               },
-              '/tmp/project-b': {
+              [PROJECT_B_PATH]: {
                 mcpServers: {
                   github: { command: 'uvx github-mcp' },
                 },
@@ -112,7 +122,7 @@ describe('McpInstallationStateService', () => {
           });
         }
 
-        if (normalizedPath === '/tmp/project-a/.mcp.json') {
+        if (normalizedPath === normalizeMockPath(path.join(PROJECT_A_PATH, '.mcp.json'))) {
           return JSON.stringify({
             mcpServers: {
               'repo-a-server': { url: 'https://repo-a.example.com/mcp' },
@@ -120,7 +130,7 @@ describe('McpInstallationStateService', () => {
           });
         }
 
-        if (normalizedPath === '/tmp/project-b/.mcp.json') {
+        if (normalizedPath === normalizeMockPath(path.join(PROJECT_B_PATH, '.mcp.json'))) {
           return JSON.stringify({
             mcpServers: {
               'repo-b-server': { command: 'uvx repo-b-mcp' },
@@ -131,8 +141,8 @@ describe('McpInstallationStateService', () => {
         throw Object.assign(new Error('ENOENT'), { code: 'ENOENT' });
       });
 
-      const projectAEntries = await service.getInstalled('/tmp/project-a');
-      const projectBEntries = await service.getInstalled('/tmp/project-b');
+      const projectAEntries = await service.getInstalled(PROJECT_A_PATH);
+      const projectBEntries = await service.getInstalled(PROJECT_B_PATH);
 
       expect(projectAEntries).toEqual([
         { name: 'context7', scope: 'user', transport: 'stdio' },
diff --git a/test/main/services/extensions/PluginInstallationStateService.test.ts b/test/main/services/extensions/PluginInstallationStateService.test.ts
index 5bec6049..f7c71536 100644
--- a/test/main/services/extensions/PluginInstallationStateService.test.ts
+++ b/test/main/services/extensions/PluginInstallationStateService.test.ts
@@ -9,7 +9,7 @@ const MOCK_CLAUDE_BASE_PATH = path.join(TEST_ROOT, 'tmp', 'mock-claude');
 const PROJECT_A_PATH = path.join(TEST_ROOT, 'tmp', 'project-a');
 const PROJECT_B_PATH = path.join(TEST_ROOT, 'tmp', 'project-b');
 
-function normalizeMockPath(filePath: string | URL): string {
+function normalizeMockPath(filePath: unknown): string {
   return String(filePath).replaceAll('\\', '/');
 }
 
diff --git a/test/renderer/components/extensions/plugins/PluginDetailDialog.test.ts b/test/renderer/components/extensions/plugins/PluginDetailDialog.test.ts
index 753761f8..9a7157a0 100644
--- a/test/renderer/components/extensions/plugins/PluginDetailDialog.test.ts
+++ b/test/renderer/components/extensions/plugins/PluginDetailDialog.test.ts
@@ -257,9 +257,15 @@ describe('PluginDetailDialog project context', () => {
     });
 
     const scopeSelect = host.querySelector('[data-testid="scope-select"]') as HTMLSelectElement;
+    const projectOption = scopeSelect.querySelector(
+      'option[value="project"]'
+    ) as HTMLOptionElement | null;
+    const localOption = scopeSelect.querySelector(
+      'option[value="local"]'
+    ) as HTMLOptionElement | null;
     expect(scopeSelect).not.toBeNull();
-    expect(scopeSelect.querySelector('option[value="project"]')?.disabled).toBe(true);
-    expect(scopeSelect.querySelector('option[value="local"]')?.disabled).toBe(true);
+    expect(projectOption?.disabled).toBe(true);
+    expect(localOption?.disabled).toBe(true);
 
     await act(async () => {
       root.unmount();