diff --git a/packages/cli/src/commands/extensions/utils.test.ts b/packages/cli/src/commands/extensions/utils.test.ts
index 2168d2d7c..278ee7a54 100644
--- a/packages/cli/src/commands/extensions/utils.test.ts
+++ b/packages/cli/src/commands/extensions/utils.test.ts
@@ -5,7 +5,8 @@
  */
 
 import { describe, it, expect, vi, beforeEach } from 'vitest';
-import { getExtensionManager } from './utils.js';
+import { getExtensionManager, extensionToOutputString } from './utils.js';
+import type { Extension, ExtensionManager } from '@qwen-code/qwen-code-core';
 
 const mockRefreshCache = vi.fn();
 const mockExtensionManagerInstance = {
@@ -64,3 +65,70 @@ describe('getExtensionManager', () => {
     );
   });
 });
+
+describe('extensionToOutputString', () => {
+  const mockIsEnabled = vi.fn();
+  const mockExtensionManager = {
+    isEnabled: mockIsEnabled,
+  } as unknown as ExtensionManager;
+
+  const createMockExtension = (overrides = {}): Extension => ({
+    id: 'test-ext-id',
+    name: 'test-extension',
+    version: '1.0.0',
+    isActive: true,
+    path: '/path/to/extension',
+    contextFiles: [],
+    config: { name: 'test-extension', version: '1.0.0' },
+    ...overrides,
+  });
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockIsEnabled.mockReturnValue(true);
+  });
+
+  it('should include status icon when inline is false', () => {
+    const extension = createMockExtension();
+    const result = extensionToOutputString(
+      extension,
+      mockExtensionManager,
+      '/workspace',
+      false,
+    );
+
+    // Should contain either ✓ or ✗ (with ANSI color codes)
+    expect(result).toMatch(/test-extension/);
+    expect(result).toContain('(1.0.0)');
+  });
+
+  it('should exclude status icon when inline is true', () => {
+    const extension = createMockExtension();
+    const result = extensionToOutputString(
+      extension,
+      mockExtensionManager,
+      '/workspace',
+      true,
+    );
+
+    // Should start with extension name (after stripping potential whitespace)
+    expect(result.trim()).toMatch(/^test-extension/);
+  });
+
+  it('should default inline to false', () => {
+    const extension = createMockExtension();
+    const resultWithoutInline = extensionToOutputString(
+      extension,
+      mockExtensionManager,
+      '/workspace',
+    );
+    const resultWithInlineFalse = extensionToOutputString(
+      extension,
+      mockExtensionManager,
+      '/workspace',
+      false,
+    );
+
+    expect(resultWithoutInline).toEqual(resultWithInlineFalse);
+  });
+});
diff --git a/packages/cli/src/commands/extensions/utils.ts b/packages/cli/src/commands/extensions/utils.ts
index b7605f32c..97e7a8d2f 100644
--- a/packages/cli/src/commands/extensions/utils.ts
+++ b/packages/cli/src/commands/extensions/utils.ts
@@ -32,6 +32,7 @@ export function extensionToOutputString(
   extension: Extension,
   extensionManager: ExtensionManager,
   workspaceDir: string,
+  inline = false,
 ): string {
   const cwd = workspaceDir;
   const userEnabled = extensionManager.isEnabled(
@@ -44,7 +45,7 @@ export function extensionToOutputString(
   );
 
   const status = workspaceEnabled ? chalk.green('✓') : chalk.red('✗');
-  let output = `${status} ${extension.config.name} (${extension.config.version})`;
+  let output = `${inline ? '' : status} ${extension.config.name} (${extension.config.version})`;
   output += `\n Path: ${extension.path}`;
   if (extension.installMetadata) {
     output += `\n Source: ${extension.installMetadata.source} (Type: ${extension.installMetadata.type})`;
diff --git a/packages/cli/src/ui/commands/extensionsCommand.test.ts b/packages/cli/src/ui/commands/extensionsCommand.test.ts
index bad4b87f2..c14fdb389 100644
--- a/packages/cli/src/ui/commands/extensionsCommand.test.ts
+++ b/packages/cli/src/ui/commands/extensionsCommand.test.ts
@@ -777,4 +777,87 @@ describe('extensionsCommand', () => {
       );
     });
   });
+
+  describe('detail', () => {
+    const detailAction = extensionsCommand.subCommands?.find(
+      (cmd) => cmd.name === 'detail',
+    )?.action;
+
+    if (!detailAction) {
+      throw new Error('Detail action not found');
+    }
+
+    let realMockExtensionManager: ExtensionManager;
+
+    beforeEach(() => {
+      vi.resetAllMocks();
+      realMockExtensionManager = Object.create(ExtensionManager.prototype);
+      realMockExtensionManager.getLoadedExtensions = mockGetLoadedExtensions;
+
+      mockContext = createMockCommandContext({
+        invocation: {
+          raw: '/extensions detail',
+          name: 'detail',
+          args: '',
+        },
+        services: {
+          config: {
+            getExtensions: mockGetExtensions,
+            getWorkingDir: () => '/test/dir',
+            getExtensionManager: () => realMockExtensionManager,
+          },
+        },
+        ui: {
+          dispatchExtensionStateUpdate: vi.fn(),
+        },
+      });
+    });
+
+    it('should show usage if no name is provided', async () => {
+      await detailAction(mockContext, '');
+      expect(mockContext.ui.addItem).toHaveBeenCalledWith(
+        {
+          type: MessageType.ERROR,
+          text: 'Usage: /extensions detail <extension-name>',
+        },
+        expect.any(Number),
+      );
+    });
+
+    it('should show error if extension not found', async () => {
+      mockGetExtensions.mockReturnValue([]);
+      await detailAction(mockContext, 'nonexistent-extension');
+      expect(mockContext.ui.addItem).toHaveBeenCalledWith(
+        {
+          type: MessageType.ERROR,
+          text: 'Extension "nonexistent-extension" not found.',
+        },
+        expect.any(Number),
+      );
+    });
+
+    it('should show extension details when found', async () => {
+      const extension: Extension = {
+        id: 'test-ext',
+        name: 'test-ext',
+        version: '1.0.0',
+        isActive: true,
+        path: '/test/dir/test-ext',
+        contextFiles: [],
+        config: { name: 'test-ext', version: '1.0.0' },
+      };
+      mockGetExtensions.mockReturnValue([extension]);
+      realMockExtensionManager.isEnabled = vi.fn().mockReturnValue(true);
+
+      await detailAction(mockContext, 'test-ext');
+
+      expect(mockContext.ui.addItem).toHaveBeenCalledWith(
+        {
+          type: MessageType.INFO,
+          text: expect.stringContaining('test-ext'),
+        },
+        expect.any(Number),
+      );
+    });
+  });
 });
diff --git a/packages/cli/src/ui/commands/extensionsCommand.ts b/packages/cli/src/ui/commands/extensionsCommand.ts
index c14365a71..e13df24f7 100644
--- a/packages/cli/src/ui/commands/extensionsCommand.ts
+++ b/packages/cli/src/ui/commands/extensionsCommand.ts
@@ -20,6 +20,7 @@ import {
 } from '@qwen-code/qwen-code-core';
 import { SettingScope } from '../../config/settings.js';
 import open from 'open';
+import { extensionToOutputString } from '../../commands/extensions/utils.js';
 
 const EXTENSION_EXPLORE_URL = {
   Gemini: 'https://geminicli.com/extensions/',
@@ -475,6 +476,53 @@ async function enableAction(context: CommandContext, args: string) {
   }
 }
 
+async function detailAction(context: CommandContext, args: string) {
+  const extensionManager = context.services.config?.getExtensionManager();
+  if (!(extensionManager instanceof ExtensionManager)) {
+    console.error(
+      `Cannot ${context.invocation?.name} extensions in this environment`,
+    );
+    return;
+  }
+
+  const name = args.trim();
+  if (!name) {
+    context.ui.addItem(
+      {
+        type: MessageType.ERROR,
+        text: t('Usage: /extensions detail <extension-name>'),
+      },
+      Date.now(),
+    );
+    return;
+  }
+
+  const extensions = context.services.config!.getExtensions();
+  const extension = extensions.find((extension) => extension.name === name);
+  if (!extension) {
+    context.ui.addItem(
+      {
+        type: MessageType.ERROR,
+        text: t('Extension "{{name}}" not found.', { name }),
+      },
+      Date.now(),
+    );
+    return;
+  }
+  context.ui.addItem(
+    {
+      type: MessageType.INFO,
+      text: extensionToOutputString(
+        extension,
+        extensionManager,
+        process.cwd(),
+        true,
+      ),
+    },
+    Date.now(),
+  );
+}
+
 export async function completeExtensions(
   context: CommandContext,
   partialArg: string,
@@ -495,7 +543,10 @@ export async function completeExtensions(
     name.startsWith(partialArg),
   );
 
-  if (context.invocation?.name !== 'uninstall') {
+  if (
+    context.invocation?.name !== 'uninstall' &&
+    context.invocation?.name !== 'detail'
+  ) {
     if ('--all'.startsWith(partialArg) || 'all'.startsWith(partialArg)) {
       suggestions.unshift('--all');
     }
@@ -594,6 +645,16 @@ const uninstallCommand: SlashCommand = {
   completion: completeExtensions,
 };
 
+const detailCommand: SlashCommand = {
+  name: 'detail',
+  get description() {
+    return t('Get detail of an extension');
+  },
+  kind: CommandKind.BUILT_IN,
+  action: detailAction,
+  completion: completeExtensions,
+};
+
 export const extensionsCommand: SlashCommand = {
   name: 'extensions',
   get description() {
@@ -608,6 +669,7 @@ export const extensionsCommand: SlashCommand = {
     installCommand,
     uninstallCommand,
     exploreExtensionsCommand,
+    detailCommand,
   ],
   action: (context, args) =>
     // Default to list if no subcommand is provided
diff --git a/packages/core/src/extension/extensionManager.test.ts b/packages/core/src/extension/extensionManager.test.ts
index a155f0892..51432c43a 100644
--- a/packages/core/src/extension/extensionManager.test.ts
+++ b/packages/core/src/extension/extensionManager.test.ts
@@ -218,6 +218,30 @@ describe('extension tests', () => {
       ]);
     });
 
+    it('should use default QWEN.md when contextFileName is empty array', async () => {
+      const extDir = path.join(userExtensionsDir, 'ext-empty-context');
+      fs.mkdirSync(extDir, { recursive: true });
+      fs.writeFileSync(
+        path.join(extDir, EXTENSIONS_CONFIG_FILENAME),
+        JSON.stringify({
+          name: 'ext-empty-context',
+          version: '1.0.0',
+          contextFileName: [],
+        }),
+      );
+      fs.writeFileSync(path.join(extDir, 'QWEN.md'), 'context content');
+
+      const manager = createExtensionManager();
+      await manager.refreshCache();
+      const extensions = manager.getLoadedExtensions();
+
+      expect(extensions).toHaveLength(1);
+      const ext = extensions.find((e) => e.config.name === 'ext-empty-context');
+      expect(ext?.contextFiles).toEqual([
+        path.join(userExtensionsDir, 'ext-empty-context', 'QWEN.md'),
+      ]);
+    });
+
     it('should skip extensions with invalid JSON and log a warning', async () => {
       const consoleSpy = vi
         .spyOn(console, 'error')
@@ -694,13 +718,14 @@ describe('extension tests', () => {
         expect(() => validateName('UPPERCASE')).not.toThrow();
       });
 
+      it('should accept names with underscores and dots', () => {
+        expect(() => validateName('my_extension')).not.toThrow();
+        expect(() => validateName('my.extension')).not.toThrow();
+        expect(() => validateName('my_ext.v1')).not.toThrow();
+        expect(() => validateName('ext_1.2.3')).not.toThrow();
+      });
+
       it('should reject names with invalid characters', () => {
-        expect(() => validateName('my_extension')).toThrow(
-          'Invalid extension name',
-        );
-        expect(() => validateName('my.extension')).toThrow(
-          'Invalid extension name',
-        );
         expect(() => validateName('my extension')).toThrow(
           'Invalid extension name',
         );
diff --git a/packages/core/src/extension/extensionManager.ts b/packages/core/src/extension/extensionManager.ts
index 07522f300..628dd9b6f 100644
--- a/packages/core/src/extension/extensionManager.ts
+++ b/packages/core/src/extension/extensionManager.ts
@@ -190,7 +190,7 @@ function filterMcpConfig(original: MCPServerConfig): MCPServerConfig {
 }
 
 function getContextFileNames(config: ExtensionConfig): string[] {
-  if (!config.contextFileName) {
+  if (!config.contextFileName || config.contextFileName.length === 0) {
     return ['QWEN.md'];
   } else if (!Array.isArray(config.contextFileName)) {
     return [config.contextFileName];
@@ -1244,9 +1244,9 @@ export function hashValue(value: string): string {
 }
 
 export function validateName(name: string) {
-  if (!/^[a-zA-Z0-9-]+$/.test(name)) {
+  if (!/^[a-zA-Z0-9-_.]+$/.test(name)) {
     throw new Error(
-      `Invalid extension name: "${name}". Only letters (a-z, A-Z), numbers (0-9), and dashes (-) are allowed.`,
+      `Invalid extension name: "${name}". Only letters (a-z, A-Z), numbers (0-9), underscores (_), dots (.), and dashes (-) are allowed.`,
     );
   }
 }
diff --git a/packages/core/src/extension/github.test.ts b/packages/core/src/extension/github.test.ts
index e98e6498a..87d7d22b7 100644
--- a/packages/core/src/extension/github.test.ts
+++ b/packages/core/src/extension/github.test.ts
@@ -117,6 +117,51 @@ describe('git extension helpers', () => {
         'Failed to clone Git repository from http://my-repo.com',
       );
     });
+
+    it('should use marketplace source for marketplace type extensions', async () => {
+      const installMetadata = {
+        source: 'marketplace:my-plugin',
+        type: 'marketplace' as const,
+        marketplace: {
+          pluginName: 'my-plugin',
+          marketplaceSource: 'https://github.com/marketplace/my-plugin',
+        },
+      };
+      const destination = '/dest';
+      mockGit.getRemotes.mockResolvedValue([
+        {
+          name: 'origin',
+          refs: { fetch: 'https://github.com/marketplace/my-plugin' },
+        },
+      ]);
+
+      await cloneFromGit(installMetadata, destination);
+
+      expect(mockGit.clone).toHaveBeenCalledWith(
+        'https://github.com/marketplace/my-plugin',
+        './',
+        ['--depth', '1'],
+      );
+    });
+
+    it('should use source for marketplace type without marketplace metadata', async () => {
+      const installMetadata = {
+        source: 'http://fallback-repo.com',
+        type: 'marketplace' as const,
+      };
+      const destination = '/dest';
+      mockGit.getRemotes.mockResolvedValue([
+        { name: 'origin', refs: { fetch: 'http://fallback-repo.com' } },
+      ]);
+
+      await cloneFromGit(installMetadata, destination);
+
+      expect(mockGit.clone).toHaveBeenCalledWith(
+        'http://fallback-repo.com',
+        './',
+        ['--depth', '1'],
+      );
+    });
   });
 
   describe('checkForExtensionUpdate', () => {
diff --git a/packages/core/src/extension/github.ts b/packages/core/src/extension/github.ts
index a89c565b8..c13bcaf16 100644
--- a/packages/core/src/extension/github.ts
+++ b/packages/core/src/extension/github.ts
@@ -53,7 +53,10 @@ export async function cloneFromGit(
 ): Promise<void> {
   try {
     const git = simpleGit(destination);
-    let sourceUrl = installMetadata.source;
+    let sourceUrl =
+      installMetadata.type === 'marketplace' && installMetadata.marketplace
+        ? installMetadata.marketplace.marketplaceSource
+        : installMetadata.source;
     const token = getGitHubToken();
     if (token) {
       try {