feat(skills): implement linking for agent skills (#18295)

packages/cli/src/commands/skills.tsx

@@ -9,6 +9,7 @@ import { listCommand } from './skills/list.js';
 import { enableCommand } from './skills/enable.js';
 import { disableCommand } from './skills/disable.js';
 import { installCommand } from './skills/install.js';
+import { linkCommand } from './skills/link.js';
 import { uninstallCommand } from './skills/uninstall.js';
 import { initializeOutputListenersAndFlush } from '../gemini.js';
 import { defer } from '../deferred.js';
@@ -27,6 +28,7 @@ export const skillsCommand: CommandModule = {
       .command(defer(enableCommand, 'skills'))
       .command(defer(disableCommand, 'skills'))
       .command(defer(installCommand, 'skills'))
+      .command(defer(linkCommand, 'skills'))
       .command(defer(uninstallCommand, 'skills'))
       .demandCommand(1, 'You need at least one command before continuing.')
       .version(false),

packages/cli/src/commands/skills/link.test.ts

@@ -0,0 +1,69 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { handleLink, linkCommand } from './link.js';
+
+const mockLinkSkill = vi.hoisted(() => vi.fn());
+const mockRequestConsentNonInteractive = vi.hoisted(() => vi.fn());
+const mockSkillsConsentString = vi.hoisted(() => vi.fn());
+
+vi.mock('../../utils/skillUtils.js', () => ({
+  linkSkill: mockLinkSkill,
+}));
+
+vi.mock('@google/gemini-cli-core', () => ({
+  debugLogger: { log: vi.fn(), error: vi.fn() },
+}));
+
+vi.mock('../../config/extensions/consent.js', () => ({
+  requestConsentNonInteractive: mockRequestConsentNonInteractive,
+  skillsConsentString: mockSkillsConsentString,
+}));
+
+import { debugLogger } from '@google/gemini-cli-core';
+
+describe('skills link command', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.spyOn(process, 'exit').mockImplementation(() => undefined as never);
+  });
+
+  describe('linkCommand', () => {
+    it('should have correct command and describe', () => {
+      expect(linkCommand.command).toBe('link <path>');
+      expect(linkCommand.describe).toContain('Links an agent skill');
+    });
+  });
+
+  it('should call linkSkill with correct arguments', async () => {
+    const sourcePath = '/source/path';
+    mockLinkSkill.mockResolvedValue([
+      { name: 'test-skill', location: '/dest/path' },
+    ]);
+
+    await handleLink({ path: sourcePath, scope: 'user' });
+
+    expect(mockLinkSkill).toHaveBeenCalledWith(
+      sourcePath,
+      'user',
+      expect.any(Function),
+      expect.any(Function),
+    );
+    expect(debugLogger.log).toHaveBeenCalledWith(
+      expect.stringContaining('Successfully linked skills'),
+    );
+  });
+
+  it('should handle linkSkill failure', async () => {
+    mockLinkSkill.mockRejectedValue(new Error('Link failed'));
+
+    await handleLink({ path: '/some/path' });
+
+    expect(debugLogger.error).toHaveBeenCalledWith('Link failed');
+    expect(process.exit).toHaveBeenCalledWith(1);
+  });
+});

packages/cli/src/commands/skills/link.ts

@@ -0,0 +1,93 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { CommandModule } from 'yargs';
+import { debugLogger } from '@google/gemini-cli-core';
+import chalk from 'chalk';
+
+import { getErrorMessage } from '../../utils/errors.js';
+import { exitCli } from '../utils.js';
+import {
+  requestConsentNonInteractive,
+  skillsConsentString,
+} from '../../config/extensions/consent.js';
+import { linkSkill } from '../../utils/skillUtils.js';
+
+interface LinkArgs {
+  path: string;
+  scope?: 'user' | 'workspace';
+  consent?: boolean;
+}
+
+export async function handleLink(args: LinkArgs) {
+  try {
+    const { scope = 'user', consent } = args;
+
+    await linkSkill(
+      args.path,
+      scope,
+      (msg) => debugLogger.log(msg),
+      async (skills, targetDir) => {
+        const consentString = await skillsConsentString(
+          skills,
+          args.path,
+          targetDir,
+          true,
+        );
+        if (consent) {
+          debugLogger.log('You have consented to the following:');
+          debugLogger.log(consentString);
+          return true;
+        }
+        return requestConsentNonInteractive(consentString);
+      },
+    );
+
+    debugLogger.log(chalk.green('\nSuccessfully linked skills.'));
+  } catch (error) {
+    debugLogger.error(getErrorMessage(error));
+    await exitCli(1);
+  }
+}
+
+export const linkCommand: CommandModule = {
+  command: 'link <path>',
+  describe:
+    'Links an agent skill from a local path. Updates to the source will be reflected immediately.',
+  builder: (yargs) =>
+    yargs
+      .positional('path', {
+        describe: 'The local path of the skill to link.',
+        type: 'string',
+        demandOption: true,
+      })
+      .option('scope', {
+        describe:
+          'The scope to link the skill into. Defaults to "user" (global).',
+        choices: ['user', 'workspace'],
+        default: 'user',
+      })
+      .option('consent', {
+        describe:
+          'Acknowledge the security risks of linking a skill and skip the confirmation prompt.',
+        type: 'boolean',
+        default: false,
+      })
+      .check((argv) => {
+        if (!argv.path) {
+          throw new Error('The path argument must be provided.');
+        }
+        return true;
+      }),
+  handler: async (argv) => {
+    await handleLink({
+      path: argv['path'] as string,
+      scope: argv['scope'] as 'user' | 'workspace',
+      consent: argv['consent'] as boolean | undefined,
+    });
+    await exitCli();
+  },
+};