From 0dc69bd36420d43c8e7ac0d113dff82c13449bb3 Mon Sep 17 00:00:00 2001
From: Akihiro Suda <suda.kyoto@gmail.com>
Date: Tue, 27 Jan 2026 22:27:42 +0900
Subject: [PATCH] feat(cli): add `gemini extensions list --output-format=json`
 (#14479)

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
Co-authored-by: Bryan Morgan <bryanmorgan@google.com>
---
 .../cli/src/commands/extensions/list.test.ts  | 57 ++++++++++++++++++-
 packages/cli/src/commands/extensions/list.ts  | 42 ++++++++++----
 2 files changed, 85 insertions(+), 14 deletions(-)

diff --git a/packages/cli/src/commands/extensions/list.test.ts b/packages/cli/src/commands/extensions/list.test.ts
index cc17e6410b..6967719be8 100644
--- a/packages/cli/src/commands/extensions/list.test.ts
+++ b/packages/cli/src/commands/extensions/list.test.ts
@@ -78,6 +78,17 @@ describe('extensions list command', () => {
       mockCwd.mockRestore();
     });
 
+    it('should output empty JSON array if no extensions are installed and output-format is json', async () => {
+      const mockCwd = vi.spyOn(process, 'cwd').mockReturnValue('/test/dir');
+      mockExtensionManager.prototype.loadExtensions = vi
+        .fn()
+        .mockResolvedValue([]);
+      await handleList({ outputFormat: 'json' });
+
+      expect(emitConsoleLog).toHaveBeenCalledWith('log', '[]');
+      mockCwd.mockRestore();
+    });
+
     it('should list all installed extensions', async () => {
       const mockCwd = vi.spyOn(process, 'cwd').mockReturnValue('/test/dir');
       const extensions = [
@@ -99,6 +110,24 @@ describe('extensions list command', () => {
       mockCwd.mockRestore();
     });
 
+    it('should list all installed extensions in JSON format', async () => {
+      const mockCwd = vi.spyOn(process, 'cwd').mockReturnValue('/test/dir');
+      const extensions = [
+        { name: 'ext1', version: '1.0.0' },
+        { name: 'ext2', version: '2.0.0' },
+      ];
+      mockExtensionManager.prototype.loadExtensions = vi
+        .fn()
+        .mockResolvedValue(extensions);
+      await handleList({ outputFormat: 'json' });
+
+      expect(emitConsoleLog).toHaveBeenCalledWith(
+        'log',
+        JSON.stringify(extensions, null, 2),
+      );
+      mockCwd.mockRestore();
+    });
+
     it('should log an error message and exit with code 1 when listing fails', async () => {
       const mockProcessExit = vi
         .spyOn(process, 'exit')
@@ -130,11 +159,35 @@ describe('extensions list command', () => {
       expect(command.describe).toBe('Lists installed extensions.');
     });
 
-    it('handler should call handleList', async () => {
+    it('builder should have output-format option', () => {
+      const mockYargs = {
+        option: vi.fn().mockReturnThis(),
+      };
+      (
+        command.builder as unknown as (
+          yargs: typeof mockYargs,
+        ) => typeof mockYargs
+      )(mockYargs);
+      expect(mockYargs.option).toHaveBeenCalledWith('output-format', {
+        alias: 'o',
+        type: 'string',
+        describe: 'The format of the CLI output.',
+        choices: ['text', 'json'],
+        default: 'text',
+      });
+    });
+
+    it('handler should call handleList with parsed arguments', async () => {
       mockExtensionManager.prototype.loadExtensions = vi
         .fn()
         .mockResolvedValue([]);
-      await (command.handler as () => Promise<void>)();
+      await (
+        command.handler as unknown as (args: {
+          'output-format': string;
+        }) => Promise<void>
+      )({
+        'output-format': 'json',
+      });
       expect(mockExtensionManager.prototype.loadExtensions).toHaveBeenCalled();
     });
   });
diff --git a/packages/cli/src/commands/extensions/list.ts b/packages/cli/src/commands/extensions/list.ts
index 6faa795bd7..39a8a3f108 100644
--- a/packages/cli/src/commands/extensions/list.ts
+++ b/packages/cli/src/commands/extensions/list.ts
@@ -13,7 +13,7 @@ import { loadSettings } from '../../config/settings.js';
 import { promptForSetting } from '../../config/extensions/extensionSettings.js';
 import { exitCli } from '../utils.js';
 
-export async function handleList() {
+export async function handleList(options?: { outputFormat?: 'text' | 'json' }) {
   try {
     const workspaceDir = process.cwd();
     const extensionManager = new ExtensionManager({
@@ -24,16 +24,25 @@ export async function handleList() {
     });
     const extensions = await extensionManager.loadExtensions();
     if (extensions.length === 0) {
-      debugLogger.log('No extensions installed.');
+      if (options?.outputFormat === 'json') {
+        debugLogger.log('[]');
+      } else {
+        debugLogger.log('No extensions installed.');
+      }
       return;
     }
-    debugLogger.log(
-      extensions
-        .map((extension, _): string =>
-          extensionManager.toOutputString(extension),
-        )
-        .join('\n\n'),
-    );
+
+    if (options?.outputFormat === 'json') {
+      debugLogger.log(JSON.stringify(extensions, null, 2));
+    } else {
+      debugLogger.log(
+        extensions
+          .map((extension, _): string =>
+            extensionManager.toOutputString(extension),
+          )
+          .join('\n\n'),
+      );
+    }
   } catch (error) {
     debugLogger.error(getErrorMessage(error));
     process.exit(1);
@@ -43,9 +52,18 @@ export async function handleList() {
 export const listCommand: CommandModule = {
   command: 'list',
   describe: 'Lists installed extensions.',
-  builder: (yargs) => yargs,
-  handler: async () => {
-    await handleList();
+  builder: (yargs) =>
+    yargs.option('output-format', {
+      alias: 'o',
+      type: 'string',
+      describe: 'The format of the CLI output.',
+      choices: ['text', 'json'],
+      default: 'text',
+    }),
+  handler: async (argv) => {
+    await handleList({
+      outputFormat: argv['output-format'] as 'text' | 'json',
+    });
     await exitCli();
   },
 };