Read and write files through Zed (#6169)

Co-authored-by: Agus Zubiaga <agus@zed.dev>

packages/cli/src/ui/hooks/atCommandProcessor.test.ts

@@ -11,6 +11,7 @@ import {
   FileDiscoveryService,
   GlobTool,
   ReadManyFilesTool,
+  StandardFileSystemService,
   ToolRegistry,
 } from '@google/gemini-cli-core';
 import * as os from 'os';
@@ -56,6 +57,7 @@ describe('handleAtCommand', () => {
         respectGitIgnore: true,
         respectGeminiIgnore: true,
       }),
+      getFileSystemService: () => new StandardFileSystemService(),
       getEnableRecursiveFileSearch: vi.fn(() => true),
       getWorkspaceContext: () => ({
         isPathWithinWorkspace: () => true,

packages/cli/src/zed-integration/fileSystemService.ts

@@ -0,0 +1,47 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { FileSystemService } from '@google/gemini-cli-core';
+import * as acp from './acp.js';
+
+/**
+ * ACP client-based implementation of FileSystemService
+ */
+export class AcpFileSystemService implements FileSystemService {
+  constructor(
+    private readonly client: acp.Client,
+    private readonly sessionId: string,
+    private readonly capabilities: acp.FileSystemCapability,
+    private readonly fallback: FileSystemService,
+  ) {}
+
+  async readTextFile(filePath: string): Promise<string> {
+    if (!this.capabilities.readTextFile) {
+      return this.fallback.readTextFile(filePath);
+    }
+
+    const response = await this.client.readTextFile({
+      path: filePath,
+      sessionId: this.sessionId,
+      line: null,
+      limit: null,
+    });
+
+    return response.content;
+  }
+
+  async writeTextFile(filePath: string, content: string): Promise<void> {
+    if (!this.capabilities.writeTextFile) {
+      return this.fallback.writeTextFile(filePath, content);
+    }
+
+    await this.client.writeTextFile({
+      path: filePath,
+      content,
+      sessionId: this.sessionId,
+    });
+  }
+}

packages/cli/src/zed-integration/zedIntegration.ts

@@ -24,6 +24,7 @@ import {
   MCPServerConfig,
 } from '@google/gemini-cli-core';
 import * as acp from './acp.js';
+import { AcpFileSystemService } from './fileSystemService.js';
 import { Readable, Writable } from 'node:stream';
 import { Content, Part, FunctionCall, PartListUnion } from '@google/genai';
 import { LoadedSettings, SettingScope } from '../config/settings.js';
@@ -60,6 +61,7 @@ export async function runZedIntegration(
 
 class GeminiAgent {
   private sessions: Map<string, Session> = new Map();
+  private clientCapabilities: acp.ClientCapabilities | undefined;
 
   constructor(
     private config: Config,
@@ -70,8 +72,9 @@ class GeminiAgent {
   ) {}
 
   async initialize(
-    _args: acp.InitializeRequest,
+    args: acp.InitializeRequest,
   ): Promise<acp.InitializeResponse> {
+    this.clientCapabilities = args.clientCapabilities;
     const authMethods = [
       {
         id: AuthType.LOGIN_WITH_GOOGLE,
@@ -129,6 +132,16 @@ class GeminiAgent {
       throw acp.RequestError.authRequired();
     }
 
+    if (this.clientCapabilities?.fs) {
+      const acpFileSystemService = new AcpFileSystemService(
+        this.client,
+        sessionId,
+        this.clientCapabilities.fs,
+        config.getFileSystemService(),
+      );
+      config.setFileSystemService(acpFileSystemService);
+    }
+
     const geminiClient = config.getGeminiClient();
     const chat = await geminiClient.startChat();
     const session = new Session(sessionId, chat, config, this.client);