feat(cli): enable skill activation via slash commands (#21758)

Co-authored-by: matt korwel <matt.korwel@gmail.com>

packages/cli/src/services/SkillCommandLoader.test.ts

@@ -0,0 +1,125 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi, describe, it, expect, beforeEach } from 'vitest';
+import { SkillCommandLoader } from './SkillCommandLoader.js';
+import { CommandKind } from '../ui/commands/types.js';
+import { ACTIVATE_SKILL_TOOL_NAME } from '@google/gemini-cli-core';
+
+describe('SkillCommandLoader', () => {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  let mockConfig: any;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  let mockSkillManager: any;
+
+  beforeEach(() => {
+    mockSkillManager = {
+      getDisplayableSkills: vi.fn(),
+      isAdminEnabled: vi.fn().mockReturnValue(true),
+    };
+
+    mockConfig = {
+      isSkillsSupportEnabled: vi.fn().mockReturnValue(true),
+      getSkillManager: vi.fn().mockReturnValue(mockSkillManager),
+    };
+  });
+
+  it('should return an empty array if skills support is disabled', async () => {
+    mockConfig.isSkillsSupportEnabled.mockReturnValue(false);
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+    expect(commands).toEqual([]);
+  });
+
+  it('should return an empty array if SkillManager is missing', async () => {
+    mockConfig.getSkillManager.mockReturnValue(null);
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+    expect(commands).toEqual([]);
+  });
+
+  it('should return an empty array if skills are admin-disabled', async () => {
+    mockSkillManager.isAdminEnabled.mockReturnValue(false);
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+    expect(commands).toEqual([]);
+  });
+
+  it('should load skills as slash commands', async () => {
+    const mockSkills = [
+      { name: 'skill1', description: 'Description 1' },
+      { name: 'skill2', description: '' },
+    ];
+    mockSkillManager.getDisplayableSkills.mockReturnValue(mockSkills);
+
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+
+    expect(commands).toHaveLength(2);
+
+    expect(commands[0]).toMatchObject({
+      name: 'skill1',
+      description: 'Description 1',
+      kind: CommandKind.SKILL,
+      autoExecute: true,
+    });
+
+    expect(commands[1]).toMatchObject({
+      name: 'skill2',
+      description: 'Activate the skill2 skill',
+      kind: CommandKind.SKILL,
+      autoExecute: true,
+    });
+  });
+
+  it('should return a tool action when a skill command is executed', async () => {
+    const mockSkills = [{ name: 'test-skill', description: 'Test skill' }];
+    mockSkillManager.getDisplayableSkills.mockReturnValue(mockSkills);
+
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const actionResult = await commands[0].action!({} as any, '');
+    expect(actionResult).toEqual({
+      type: 'tool',
+      toolName: ACTIVATE_SKILL_TOOL_NAME,
+      toolArgs: { name: 'test-skill' },
+      postSubmitPrompt: undefined,
+    });
+  });
+
+  it('should return a tool action with postSubmitPrompt when args are provided', async () => {
+    const mockSkills = [{ name: 'test-skill', description: 'Test skill' }];
+    mockSkillManager.getDisplayableSkills.mockReturnValue(mockSkills);
+
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const actionResult = await commands[0].action!({} as any, 'hello world');
+    expect(actionResult).toEqual({
+      type: 'tool',
+      toolName: ACTIVATE_SKILL_TOOL_NAME,
+      toolArgs: { name: 'test-skill' },
+      postSubmitPrompt: 'hello world',
+    });
+  });
+
+  it('should sanitize skill names with spaces', async () => {
+    const mockSkills = [{ name: 'my awesome skill', description: 'Desc' }];
+    mockSkillManager.getDisplayableSkills.mockReturnValue(mockSkills);
+
+    const loader = new SkillCommandLoader(mockConfig);
+    const commands = await loader.loadCommands(new AbortController().signal);
+
+    expect(commands[0].name).toBe('my-awesome-skill');
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const actionResult = (await commands[0].action!({} as any, '')) as any;
+    expect(actionResult.toolArgs).toEqual({ name: 'my awesome skill' });
+  });
+});

packages/cli/src/services/SkillCommandLoader.ts

@@ -0,0 +1,53 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { type Config, ACTIVATE_SKILL_TOOL_NAME } from '@google/gemini-cli-core';
+import { CommandKind, type SlashCommand } from '../ui/commands/types.js';
+import { type ICommandLoader } from './types.js';
+
+/**
+ * Loads Agent Skills as slash commands.
+ */
+export class SkillCommandLoader implements ICommandLoader {
+  constructor(private config: Config | null) {}
+
+  /**
+   * Discovers all available skills from the SkillManager and converts
+   * them into executable slash commands.
+   *
+   * @param _signal An AbortSignal (unused for this synchronous loader).
+   * @returns A promise that resolves to an array of `SlashCommand` objects.
+   */
+  async loadCommands(_signal: AbortSignal): Promise<SlashCommand[]> {
+    if (!this.config || !this.config.isSkillsSupportEnabled()) {
+      return [];
+    }
+
+    const skillManager = this.config.getSkillManager();
+    if (!skillManager || !skillManager.isAdminEnabled()) {
+      return [];
+    }
+
+    // Convert all displayable skills into slash commands.
+    const skills = skillManager.getDisplayableSkills();
+
+    return skills.map((skill) => {
+      const commandName = skill.name.trim().replace(/\s+/g, '-');
+      return {
+        name: commandName,
+        description: skill.description || `Activate the ${skill.name} skill`,
+        kind: CommandKind.SKILL,
+        autoExecute: true,
+        action: async (_context, args) => ({
+          type: 'tool',
+          toolName: ACTIVATE_SKILL_TOOL_NAME,
+          toolArgs: { name: skill.name },
+          postSubmitPrompt: args.trim().length > 0 ? args.trim() : undefined,
+        }),
+      };
+    });
+  }
+}