diff --git a/packages/cli/src/zed-integration/acpResume.test.ts b/packages/cli/src/zed-integration/acpResume.test.ts
index d6e12aec25..869c27bf52 100644
--- a/packages/cli/src/zed-integration/acpResume.test.ts
+++ b/packages/cli/src/zed-integration/acpResume.test.ts
@@ -16,6 +16,7 @@ import {
 import { GeminiAgent } from './zedIntegration.js';
 import * as acp from '@agentclientprotocol/sdk';
 import {
+  ApprovalMode,
   AuthType,
   type Config,
   CoreToolCallStatus,
@@ -62,6 +63,8 @@ describe('GeminiAgent Session Resume', () => {
       storage: {
         getProjectTempDir: vi.fn().mockReturnValue('/tmp/project'),
       },
+      getApprovalMode: vi.fn().mockReturnValue('default'),
+      isPlanEnabled: vi.fn().mockReturnValue(false),
     } as unknown as Mocked<Config>;
     mockSettings = {
       merged: {
@@ -149,7 +152,28 @@ describe('GeminiAgent Session Resume', () => {
       mcpServers: [],
     });
 
-    expect(response).toEqual({});
+    expect(response).toEqual({
+      modes: {
+        availableModes: [
+          {
+            id: ApprovalMode.DEFAULT,
+            name: 'Default',
+            description: 'Prompts for approval',
+          },
+          {
+            id: ApprovalMode.AUTO_EDIT,
+            name: 'Auto Edit',
+            description: 'Auto-approves edit tools',
+          },
+          {
+            id: ApprovalMode.YOLO,
+            name: 'YOLO',
+            description: 'Auto-approves all tools',
+          },
+        ],
+        currentModeId: ApprovalMode.DEFAULT,
+      },
+    });
 
     // Verify resumeChat received the correct arguments
     expect(mockConfig.getGeminiClient().resumeChat).toHaveBeenCalledWith(
diff --git a/packages/cli/src/zed-integration/zedIntegration.test.ts b/packages/cli/src/zed-integration/zedIntegration.test.ts
index edc32f04b6..cc71dd9309 100644
--- a/packages/cli/src/zed-integration/zedIntegration.test.ts
+++ b/packages/cli/src/zed-integration/zedIntegration.test.ts
@@ -35,6 +35,7 @@ import {
 import { loadCliConfig, type CliArgs } from '../config/config.js';
 import * as fs from 'node:fs/promises';
 import * as path from 'node:path';
+import { ApprovalMode } from '@google/gemini-cli-core/src/policy/types.js';
 
 vi.mock('../config/config.js', () => ({
   loadCliConfig: vi.fn(),
@@ -119,6 +120,8 @@ describe('GeminiAgent', () => {
         subscribe: vi.fn(),
         unsubscribe: vi.fn(),
       }),
+      getApprovalMode: vi.fn().mockReturnValue('default'),
+      isPlanEnabled: vi.fn().mockReturnValue(false),
     } as unknown as Mocked<Awaited<ReturnType<typeof loadCliConfig>>>;
     mockSettings = {
       merged: {
@@ -185,6 +188,59 @@ describe('GeminiAgent', () => {
     expect(mockConfig.getGeminiClient).toHaveBeenCalled();
   });
 
+  it('should return modes without plan mode when plan is disabled', async () => {
+    mockConfig.getContentGeneratorConfig = vi.fn().mockReturnValue({
+      apiKey: 'test-key',
+    });
+    mockConfig.isPlanEnabled = vi.fn().mockReturnValue(false);
+    mockConfig.getApprovalMode = vi.fn().mockReturnValue('default');
+
+    const response = await agent.newSession({
+      cwd: '/tmp',
+      mcpServers: [],
+    });
+
+    expect(response.modes).toEqual({
+      availableModes: [
+        { id: 'default', name: 'Default', description: 'Prompts for approval' },
+        {
+          id: 'autoEdit',
+          name: 'Auto Edit',
+          description: 'Auto-approves edit tools',
+        },
+        { id: 'yolo', name: 'YOLO', description: 'Auto-approves all tools' },
+      ],
+      currentModeId: 'default',
+    });
+  });
+
+  it('should return modes with plan mode when plan is enabled', async () => {
+    mockConfig.getContentGeneratorConfig = vi.fn().mockReturnValue({
+      apiKey: 'test-key',
+    });
+    mockConfig.isPlanEnabled = vi.fn().mockReturnValue(true);
+    mockConfig.getApprovalMode = vi.fn().mockReturnValue('plan');
+
+    const response = await agent.newSession({
+      cwd: '/tmp',
+      mcpServers: [],
+    });
+
+    expect(response.modes).toEqual({
+      availableModes: [
+        { id: 'default', name: 'Default', description: 'Prompts for approval' },
+        {
+          id: 'autoEdit',
+          name: 'Auto Edit',
+          description: 'Auto-approves edit tools',
+        },
+        { id: 'yolo', name: 'YOLO', description: 'Auto-approves all tools' },
+        { id: 'plan', name: 'Plan', description: 'Read-only mode' },
+      ],
+      currentModeId: 'plan',
+    });
+  });
+
   it('should fail session creation if Gemini API key is missing', async () => {
     (loadSettings as unknown as Mock).mockImplementation(() => ({
       merged: {
@@ -306,6 +362,32 @@ describe('GeminiAgent', () => {
     expect(session.prompt).toHaveBeenCalled();
     expect(result).toEqual({ stopReason: 'end_turn' });
   });
+
+  it('should delegate setMode to session', async () => {
+    await agent.newSession({ cwd: '/tmp', mcpServers: [] });
+    const session = (
+      agent as unknown as { sessions: Map<string, Session> }
+    ).sessions.get('test-session-id');
+    if (!session) throw new Error('Session not found');
+    session.setMode = vi.fn().mockReturnValue({});
+
+    const result = await agent.setSessionMode({
+      sessionId: 'test-session-id',
+      modeId: 'plan',
+    });
+
+    expect(session.setMode).toHaveBeenCalledWith('plan');
+    expect(result).toEqual({});
+  });
+
+  it('should throw error when setting mode on non-existent session', async () => {
+    await expect(
+      agent.setSessionMode({
+        sessionId: 'unknown',
+        modeId: 'plan',
+      }),
+    ).rejects.toThrow('Session not found: unknown');
+  });
 });
 
 describe('Session', () => {
@@ -352,6 +434,8 @@ describe('Session', () => {
       getEnableRecursiveFileSearch: vi.fn().mockReturnValue(false),
       getDebugMode: vi.fn().mockReturnValue(false),
       getMessageBus: vi.fn().mockReturnValue(mockMessageBus),
+      setApprovalMode: vi.fn(),
+      isPlanEnabled: vi.fn().mockReturnValue(false),
     } as unknown as Mocked<Config>;
     mockConnection = {
       sessionUpdate: vi.fn(),
@@ -822,4 +906,17 @@ describe('Session', () => {
       ].value;
     expect(mockInstance.build).toHaveBeenCalled();
   });
+
+  it('should set mode on config', () => {
+    session.setMode(ApprovalMode.AUTO_EDIT);
+    expect(mockConfig.setApprovalMode).toHaveBeenCalledWith(
+      ApprovalMode.AUTO_EDIT,
+    );
+  });
+
+  it('should throw error for invalid mode', () => {
+    expect(() => session.setMode('invalid-mode')).toThrow(
+      'Invalid or unavailable mode: invalid-mode',
+    );
+  });
 });
diff --git a/packages/cli/src/zed-integration/zedIntegration.ts b/packages/cli/src/zed-integration/zedIntegration.ts
index 61c255a21c..44b1890ce2 100644
--- a/packages/cli/src/zed-integration/zedIntegration.ts
+++ b/packages/cli/src/zed-integration/zedIntegration.ts
@@ -36,6 +36,7 @@ import {
   Kind,
   partListUnionToString,
   LlmRole,
+  ApprovalMode,
 } from '@google/gemini-cli-core';
 import * as acp from '@agentclientprotocol/sdk';
 import { AcpFileSystemService } from './fileSystemService.js';
@@ -225,6 +226,10 @@ export class GeminiAgent {
 
     return {
       sessionId,
+      modes: {
+        availableModes: buildAvailableModes(config.isPlanEnabled()),
+        currentModeId: config.getApprovalMode(),
+      },
     };
   }
 
@@ -276,7 +281,12 @@ export class GeminiAgent {
     // eslint-disable-next-line @typescript-eslint/no-floating-promises
     session.streamHistory(sessionData.messages);
 
-    return {};
+    return {
+      modes: {
+        availableModes: buildAvailableModes(config.isPlanEnabled()),
+        currentModeId: config.getApprovalMode(),
+      },
+    };
   }
 
   private async initializeSessionConfig(
@@ -377,6 +387,16 @@ export class GeminiAgent {
     }
     return session.prompt(params);
   }
+
+  async setSessionMode(
+    params: acp.SetSessionModeRequest,
+  ): Promise<acp.SetSessionModeResponse> {
+    const session = this.sessions.get(params.sessionId);
+    if (!session) {
+      throw new Error(`Session not found: ${params.sessionId}`);
+    }
+    return session.setMode(params.modeId);
+  }
 }
 
 export class Session {
@@ -398,6 +418,17 @@ export class Session {
     this.pendingPrompt = null;
   }
 
+  setMode(modeId: acp.SessionModeId): acp.SetSessionModeResponse {
+    const availableModes = buildAvailableModes(this.config.isPlanEnabled());
+    const mode = availableModes.find((m) => m.id === modeId);
+    if (!mode) {
+      throw new Error(`Invalid or unavailable mode: ${modeId}`);
+    }
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
+    this.config.setApprovalMode(mode.id as ApprovalMode);
+    return {};
+  }
+
   async streamHistory(messages: ConversationRecord['messages']): Promise<void> {
     for (const msg of messages) {
       const contentString = partListUnionToString(msg.content);
@@ -1273,3 +1304,33 @@ function toAcpToolKind(kind: Kind): acp.ToolKind {
       return 'other';
   }
 }
+
+function buildAvailableModes(isPlanEnabled: boolean): acp.SessionMode[] {
+  const modes: acp.SessionMode[] = [
+    {
+      id: ApprovalMode.DEFAULT,
+      name: 'Default',
+      description: 'Prompts for approval',
+    },
+    {
+      id: ApprovalMode.AUTO_EDIT,
+      name: 'Auto Edit',
+      description: 'Auto-approves edit tools',
+    },
+    {
+      id: ApprovalMode.YOLO,
+      name: 'YOLO',
+      description: 'Auto-approves all tools',
+    },
+  ];
+
+  if (isPlanEnabled) {
+    modes.push({
+      id: ApprovalMode.PLAN,
+      name: 'Plan',
+      description: 'Read-only mode',
+    });
+  }
+
+  return modes;
+}