feat(acp): support set_mode interface (#18890) (#18891)

Co-authored-by: Mervap <megavaprold@gmail.com>

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;
+}