feat(plan): implement plan slash command

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

@@ -115,6 +115,7 @@ describe('BuiltinCommandLoader', () => {
     vi.clearAllMocks();
     mockConfig = {
       getFolderTrust: vi.fn().mockReturnValue(true),
+      isPlanEnabled: vi.fn().mockReturnValue(false),
       getEnableExtensionReloading: () => false,
       getEnableHooks: () => false,
       getEnableHooksUI: () => false,
@@ -256,6 +257,7 @@ describe('BuiltinCommandLoader profile', () => {
     vi.resetModules();
     mockConfig = {
       getFolderTrust: vi.fn().mockReturnValue(false),
+      isPlanEnabled: vi.fn().mockReturnValue(false),
       getCheckpointingEnabled: () => false,
       getEnableExtensionReloading: () => false,
       getEnableHooks: () => false,

packages/cli/src/services/BuiltinCommandLoader.ts

@@ -40,8 +40,9 @@ import { memoryCommand } from '../ui/commands/memoryCommand.js';
 import { modelCommand } from '../ui/commands/modelCommand.js';
 import { oncallCommand } from '../ui/commands/oncallCommand.js';
 import { permissionsCommand } from '../ui/commands/permissionsCommand.js';
-import { privacyCommand } from '../ui/commands/privacyCommand.js';
+import { planCommand } from '../ui/commands/planCommand.js';
 import { policiesCommand } from '../ui/commands/policiesCommand.js';
+import { privacyCommand } from '../ui/commands/privacyCommand.js';
 import { profileCommand } from '../ui/commands/profileCommand.js';
 import { quitCommand } from '../ui/commands/quitCommand.js';
 import { restoreCommand } from '../ui/commands/restoreCommand.js';
@@ -142,8 +143,9 @@ export class BuiltinCommandLoader implements ICommandLoader {
       memoryCommand,
       modelCommand,
       ...(this.config?.getFolderTrust() ? [permissionsCommand] : []),
-      privacyCommand,
+      ...(this.config?.isPlanEnabled() ? [planCommand] : []),
       policiesCommand,
+      privacyCommand,
       ...(isDevelopment ? [profileCommand] : []),
       quitCommand,
       restoreCommand(this.config),

packages/cli/src/ui/commands/planCommand.test.ts

@@ -0,0 +1,133 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, beforeEach, vi, afterEach } from 'vitest';
+import { planCommand } from './planCommand.js';
+import { type CommandContext } from './types.js';
+import { createMockCommandContext } from '../../test-utils/mockCommandContext.js';
+import { MessageType } from '../types.js';
+import {
+  ApprovalMode,
+  coreEvents,
+  processSingleFileContent,
+  type ProcessedFileReadResult,
+} from '@google/gemini-cli-core';
+
+vi.mock('@google/gemini-cli-core', async (importOriginal) => {
+  const actual =
+    await importOriginal<typeof import('@google/gemini-cli-core')>();
+  return {
+    ...actual,
+    coreEvents: {
+      emitFeedback: vi.fn(),
+    },
+    processSingleFileContent: vi.fn(),
+    partToString: vi.fn((val) => val),
+  };
+});
+
+vi.mock('node:path', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('node:path')>();
+  return {
+    ...actual,
+    default: { ...actual },
+    join: vi.fn((...args) => args.join('/')),
+  };
+});
+
+describe('planCommand', () => {
+  let mockContext: CommandContext;
+
+  beforeEach(() => {
+    mockContext = createMockCommandContext({
+      services: {
+        config: {
+          isPlanEnabled: vi.fn(),
+          setApprovalMode: vi.fn(),
+          getApprovedPlanPath: vi.fn(),
+          getApprovalMode: vi.fn(),
+          getFileSystemService: vi.fn(),
+          storage: {
+            getProjectTempPlansDir: vi.fn().mockReturnValue('/mock/plans/dir'),
+          },
+        },
+      },
+      ui: {
+        addItem: vi.fn(),
+      },
+    } as unknown as CommandContext);
+
+    vi.clearAllMocks();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('should have the correct name and description', () => {
+    expect(planCommand.name).toBe('plan');
+    expect(planCommand.description).toBe(
+      'Switch to Plan Mode and view current plan',
+    );
+  });
+
+  it('should switch to plan mode if enabled', async () => {
+    vi.mocked(mockContext.services.config!.isPlanEnabled).mockReturnValue(true);
+    vi.mocked(mockContext.services.config!.getApprovedPlanPath).mockReturnValue(
+      undefined,
+    );
+
+    if (!planCommand.action) throw new Error('Action missing');
+    await planCommand.action(mockContext, '');
+
+    expect(mockContext.services.config!.setApprovalMode).toHaveBeenCalledWith(
+      ApprovalMode.PLAN,
+    );
+    expect(coreEvents.emitFeedback).toHaveBeenCalledWith(
+      'info',
+      'Switched to Plan Mode.',
+    );
+  });
+
+  it('should show "No approved plan found" if no approved plan path in config', async () => {
+    vi.mocked(mockContext.services.config!.isPlanEnabled).mockReturnValue(true);
+    vi.mocked(mockContext.services.config!.getApprovedPlanPath).mockReturnValue(
+      undefined,
+    );
+
+    if (!planCommand.action) throw new Error('Action missing');
+    await planCommand.action(mockContext, '');
+
+    expect(coreEvents.emitFeedback).toHaveBeenCalledWith(
+      'error',
+      'No approved plan found. Please create and approve a plan first.',
+    );
+  });
+
+  it('should display the approved plan from config', async () => {
+    const mockPlanPath = '/mock/plans/dir/approved-plan.md';
+    vi.mocked(mockContext.services.config!.isPlanEnabled).mockReturnValue(true);
+    vi.mocked(mockContext.services.config!.getApprovedPlanPath).mockReturnValue(
+      mockPlanPath,
+    );
+    vi.mocked(processSingleFileContent).mockResolvedValue({
+      llmContent: '# Approved Plan Content',
+      returnDisplay: '# Approved Plan Content',
+    } as ProcessedFileReadResult);
+
+    if (!planCommand.action) throw new Error('Action missing');
+    await planCommand.action(mockContext, '');
+
+    expect(coreEvents.emitFeedback).toHaveBeenCalledWith(
+      'info',
+      'Approved Plan: approved-plan.md',
+    );
+    expect(mockContext.ui.addItem).toHaveBeenCalledWith({
+      type: MessageType.GEMINI,
+      text: '# Approved Plan Content',
+    });
+  });
+});

packages/cli/src/ui/commands/planCommand.ts

@@ -0,0 +1,69 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { CommandKind, type SlashCommand } from './types.js';
+import {
+  ApprovalMode,
+  coreEvents,
+  debugLogger,
+  processSingleFileContent,
+  partToString,
+} from '@google/gemini-cli-core';
+import { MessageType } from '../types.js';
+import * as path from 'node:path';
+
+export const planCommand: SlashCommand = {
+  name: 'plan',
+  description: 'Switch to Plan Mode and view current plan',
+  kind: CommandKind.BUILT_IN,
+  autoExecute: true,
+  action: async (context) => {
+    const config = context.services.config;
+    if (!config) {
+      debugLogger.debug('Plan command: config is not available in context');
+      return;
+    }
+
+    const previousApprovalMode = config.getApprovalMode();
+    config.setApprovalMode(ApprovalMode.PLAN);
+
+    if (previousApprovalMode !== ApprovalMode.PLAN) {
+      coreEvents.emitFeedback('info', 'Switched to Plan Mode.');
+    }
+
+    const approvedPlanPath = config.getApprovedPlanPath();
+
+    if (!approvedPlanPath) {
+      coreEvents.emitFeedback(
+        'error',
+        'No approved plan found. Please create and approve a plan first.',
+      );
+      return;
+    }
+
+    try {
+      const content = await processSingleFileContent(
+        approvedPlanPath,
+        config.storage.getProjectTempPlansDir(),
+        config.getFileSystemService(),
+      );
+      const fileName = path.basename(approvedPlanPath);
+
+      coreEvents.emitFeedback('info', `Approved Plan: ${fileName}`);
+
+      context.ui.addItem({
+        type: MessageType.GEMINI,
+        text: partToString(content.llmContent),
+      });
+    } catch (error) {
+      coreEvents.emitFeedback(
+        'error',
+        `Failed to read approved plan at ${approvedPlanPath}: ${error}`,
+        error,
+      );
+    }
+  },
+};

packages/core/src/config/config.ts

@@ -627,9 +627,12 @@ export class Config {
   private latestApiRequest: GenerateContentParameters | undefined;
   private lastModeSwitchTime: number = Date.now();
 
+  private approvedPlanPath: string | undefined;
+
   constructor(params: ConfigParameters) {
     this.sessionId = params.sessionId;
     this.clientVersion = params.clientVersion ?? 'unknown';
+    this.approvedPlanPath = undefined;
     this.embeddingModel =
       params.embeddingModel ?? DEFAULT_GEMINI_EMBEDDING_MODEL;
     this.fileSystemService = new StandardFileSystemService();
@@ -1706,6 +1709,14 @@ export class Config {
     return this.planEnabled;
   }
 
+  getApprovedPlanPath(): string | undefined {
+    return this.approvedPlanPath;
+  }
+
+  setApprovedPlanPath(path: string | undefined): void {
+    this.approvedPlanPath = path;
+  }
+
   isAgentsEnabled(): boolean {
     return this.enableAgents;
   }

packages/core/src/tools/exit-plan-mode.test.ts

@@ -38,6 +38,7 @@ describe('ExitPlanModeTool', () => {
     mockConfig = {
       getTargetDir: vi.fn().mockReturnValue(tempRootDir),
       setApprovalMode: vi.fn(),
+      setApprovedPlanPath: vi.fn(),
       storage: {
         getProjectTempPlansDir: vi.fn().mockReturnValue(mockPlansDir),
       } as unknown as Config['storage'],
@@ -200,6 +201,7 @@ The approved implementation plan is stored at: ${expectedPath}
 Read and follow the plan strictly during implementation.`,
         returnDisplay: `Plan approved: ${expectedPath}`,
       });
+      expect(mockConfig.setApprovedPlanPath).toHaveBeenCalledWith(expectedPath);
     });
 
     it('should return approval message when plan is approved with AUTO_EDIT mode', async () => {
@@ -230,6 +232,7 @@ Read and follow the plan strictly during implementation.`,
       expect(mockConfig.setApprovalMode).toHaveBeenCalledWith(
         ApprovalMode.AUTO_EDIT,
       );
+      expect(mockConfig.setApprovedPlanPath).toHaveBeenCalledWith(expectedPath);
     });
 
     it('should return feedback message when plan is rejected with feedback', async () => {

packages/core/src/tools/exit-plan-mode.ts

@@ -224,6 +224,7 @@ export class ExitPlanModeInvocation extends BaseToolInvocation<
     if (payload?.approved) {
       const newMode = payload.approvalMode ?? ApprovalMode.DEFAULT;
       this.config.setApprovalMode(newMode);
+      this.config.setApprovedPlanPath(resolvedPlanPath);
 
       const description = getApprovalModeDescription(newMode);