[ide-mode] Keep track of recently-opened files and send them to the CLI (#4463)

package-lock.json

@@ -11891,7 +11891,8 @@
         "esbuild": "^0.25.3",
         "eslint": "^9.25.1",
         "npm-run-all": "^4.1.5",
-        "typescript": "^5.8.3"
+        "typescript": "^5.8.3",
+        "vitest": "^3.2.4"
       },
       "engines": {
         "vscode": "^1.101.0"

packages/core/src/services/ideContext.ts

@@ -26,6 +26,14 @@ export type Cursor = z.infer<typeof CursorSchema>;
 export const ActiveFileSchema = z.object({
   filePath: z.string(),
   cursor: CursorSchema.optional(),
+  recentOpenFiles: z
+    .array(
+      z.object({
+        filePath: z.string(),
+        timestamp: z.number(),
+      }),
+    )
+    .optional(),
 });
 export type ActiveFile = z.infer<typeof ActiveFileSchema>;
 

packages/vscode-ide-companion/package.json

@@ -30,8 +30,8 @@
     "package": "vsce package --no-dependencies",
     "check-types": "tsc --noEmit",
     "lint": "eslint src",
-    "test": "echo \"vscode-ide-companion has no tests yet\"",
-    "test:ci": "echo \"vscode-ide-companion has no tests yet\""
+    "test": "vitest run",
+    "test:ci": "vitest run --coverage"
   },
   "devDependencies": {
     "@types/cors": "^2.8.19",
@@ -43,7 +43,8 @@
     "esbuild": "^0.25.3",
     "eslint": "^9.25.1",
     "npm-run-all": "^4.1.5",
-    "typescript": "^5.8.3"
+    "typescript": "^5.8.3",
+    "vitest": "^3.2.4"
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.15.1",

packages/vscode-ide-companion/src/extension.ts

@@ -12,7 +12,6 @@ let logger: vscode.OutputChannel;
 
 export async function activate(context: vscode.ExtensionContext) {
   logger = vscode.window.createOutputChannel('Gemini CLI IDE Companion');
-  logger.show();
   logger.appendLine('Starting Gemini CLI IDE Companion server...');
   ideServer = new IDEServer(logger);
   try {

packages/vscode-ide-companion/src/ide-server.ts

@@ -14,6 +14,7 @@ import {
   type JSONRPCNotification,
 } from '@modelcontextprotocol/sdk/types.js';
 import { Server as HTTPServer } from 'node:http';
+import { RecentFilesManager } from './recent-files-manager.js';
 
 const MCP_SESSION_ID_HEADER = 'mcp-session-id';
 const IDE_SERVER_PORT_ENV_VAR = 'GEMINI_CLI_IDE_SERVER_PORT';
@@ -21,6 +22,7 @@ const IDE_SERVER_PORT_ENV_VAR = 'GEMINI_CLI_IDE_SERVER_PORT';
 function sendActiveFileChangedNotification(
   transport: StreamableHTTPServerTransport,
   logger: vscode.OutputChannel,
+  recentFilesManager: RecentFilesManager,
 ) {
   const editor = vscode.window.activeTextEditor;
   const filePath = editor ? editor.document.uri.fsPath : '';
@@ -28,7 +30,10 @@ function sendActiveFileChangedNotification(
   const notification: JSONRPCNotification = {
     jsonrpc: '2.0',
     method: 'ide/activeFileChanged',
-    params: { filePath },
+    params: {
+      filePath,
+      recentOpenFiles: recentFilesManager.recentFiles,
+    },
   };
   transport.send(notification);
 }
@@ -52,9 +57,14 @@ export class IDEServer {
     app.use(express.json());
     const mcpServer = createMcpServer();
 
-    const disposable = vscode.window.onDidChangeActiveTextEditor((_editor) => {
+    const recentFilesManager = new RecentFilesManager(context);
+    const disposable = recentFilesManager.onDidChange(() => {
       for (const transport of Object.values(transports)) {
-        sendActiveFileChangedNotification(transport, this.logger);
+        sendActiveFileChangedNotification(
+          transport,
+          this.logger,
+          recentFilesManager,
+        );
       }
     });
     context.subscriptions.push(disposable);
@@ -158,7 +168,11 @@ export class IDEServer {
       }
 
       if (!sessionsWithInitialNotification.has(sessionId)) {
-        sendActiveFileChangedNotification(transport, this.logger);
+        sendActiveFileChangedNotification(
+          transport,
+          this.logger,
+          recentFilesManager,
+        );
         sessionsWithInitialNotification.add(sessionId);
       }
     };

packages/vscode-ide-companion/src/recent-files-manager.test.ts

@@ -0,0 +1,211 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import * as vscode from 'vscode';
+import {
+  RecentFilesManager,
+  MAX_FILES,
+  MAX_FILE_AGE_MINUTES,
+} from './recent-files-manager.js';
+
+vi.mock('vscode', () => ({
+  EventEmitter: vi.fn(() => ({
+    event: vi.fn(),
+    fire: vi.fn(),
+    dispose: vi.fn(),
+  })),
+  window: {
+    onDidChangeActiveTextEditor: vi.fn(),
+  },
+  workspace: {
+    onDidDeleteFiles: vi.fn(),
+    onDidCloseTextDocument: vi.fn(),
+    onDidRenameFiles: vi.fn(),
+  },
+  Uri: {
+    file: (path: string) => ({
+      fsPath: path,
+    }),
+  },
+}));
+
+describe('RecentFilesManager', () => {
+  let context: vscode.ExtensionContext;
+
+  beforeEach(() => {
+    context = {
+      subscriptions: [],
+    } as unknown as vscode.ExtensionContext;
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('adds a file to the list', () => {
+    const manager = new RecentFilesManager(context);
+    const uri = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri);
+    expect(manager.recentFiles).toHaveLength(1);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file1.txt');
+  });
+
+  it('moves an existing file to the top', () => {
+    const manager = new RecentFilesManager(context);
+    const uri1 = vscode.Uri.file('/test/file1.txt');
+    const uri2 = vscode.Uri.file('/test/file2.txt');
+    manager.add(uri1);
+    manager.add(uri2);
+    manager.add(uri1);
+    expect(manager.recentFiles).toHaveLength(2);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file1.txt');
+  });
+
+  it('does not exceed the max number of files', () => {
+    const manager = new RecentFilesManager(context);
+    for (let i = 0; i < MAX_FILES + 5; i++) {
+      const uri = vscode.Uri.file(`/test/file${i}.txt`);
+      manager.add(uri);
+    }
+    expect(manager.recentFiles).toHaveLength(MAX_FILES);
+    expect(manager.recentFiles[0].filePath).toBe(
+      `/test/file${MAX_FILES + 4}.txt`,
+    );
+    expect(manager.recentFiles[MAX_FILES - 1].filePath).toBe(`/test/file5.txt`);
+  });
+
+  it('fires onDidChange when a file is added', () => {
+    const manager = new RecentFilesManager(context);
+    const spy = vi.spyOn(manager['onDidChangeEmitter'], 'fire');
+    const uri = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri);
+    expect(spy).toHaveBeenCalled();
+  });
+
+  it('removes a file when it is closed', () => {
+    const manager = new RecentFilesManager(context);
+    const uri = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri);
+    expect(manager.recentFiles).toHaveLength(1);
+
+    // Simulate closing the file
+    const closeHandler = vi.mocked(vscode.workspace.onDidCloseTextDocument).mock
+      .calls[0][0];
+    closeHandler({ uri } as vscode.TextDocument);
+
+    expect(manager.recentFiles).toHaveLength(0);
+  });
+
+  it('fires onDidChange when a file is removed', () => {
+    const manager = new RecentFilesManager(context);
+    const uri = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri);
+
+    const spy = vi.spyOn(manager['onDidChangeEmitter'], 'fire');
+    const closeHandler = vi.mocked(vscode.workspace.onDidCloseTextDocument).mock
+      .calls[0][0];
+    closeHandler({ uri } as vscode.TextDocument);
+
+    expect(spy).toHaveBeenCalled();
+  });
+
+  it('removes a file when it is deleted', () => {
+    const manager = new RecentFilesManager(context);
+    const uri1 = vscode.Uri.file('/test/file1.txt');
+    const uri2 = vscode.Uri.file('/test/file2.txt');
+    manager.add(uri1);
+    manager.add(uri2);
+    expect(manager.recentFiles).toHaveLength(2);
+
+    // Simulate deleting a file
+    const deleteHandler = vi.mocked(vscode.workspace.onDidDeleteFiles).mock
+      .calls[0][0];
+    deleteHandler({ files: [uri1] });
+
+    expect(manager.recentFiles).toHaveLength(1);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file2.txt');
+  });
+
+  it('fires onDidChange when a file is deleted', () => {
+    const manager = new RecentFilesManager(context);
+    const uri = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri);
+
+    const spy = vi.spyOn(manager['onDidChangeEmitter'], 'fire');
+    const deleteHandler = vi.mocked(vscode.workspace.onDidDeleteFiles).mock
+      .calls[0][0];
+    deleteHandler({ files: [uri] });
+
+    expect(spy).toHaveBeenCalled();
+  });
+
+  it('removes multiple files when they are deleted', () => {
+    const manager = new RecentFilesManager(context);
+    const uri1 = vscode.Uri.file('/test/file1.txt');
+    const uri2 = vscode.Uri.file('/test/file2.txt');
+    const uri3 = vscode.Uri.file('/test/file3.txt');
+    manager.add(uri1);
+    manager.add(uri2);
+    manager.add(uri3);
+    expect(manager.recentFiles).toHaveLength(3);
+
+    // Simulate deleting multiple files
+    const deleteHandler = vi.mocked(vscode.workspace.onDidDeleteFiles).mock
+      .calls[0][0];
+    deleteHandler({ files: [uri1, uri3] });
+
+    expect(manager.recentFiles).toHaveLength(1);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file2.txt');
+  });
+
+  it('prunes files older than the max age', () => {
+    vi.useFakeTimers();
+
+    const manager = new RecentFilesManager(context);
+    const uri1 = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri1);
+
+    // Advance time by more than the max age
+    const twoMinutesMs = (MAX_FILE_AGE_MINUTES + 1) * 60 * 1000;
+    vi.advanceTimersByTime(twoMinutesMs);
+
+    const uri2 = vscode.Uri.file('/test/file2.txt');
+    manager.add(uri2);
+
+    expect(manager.recentFiles).toHaveLength(1);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file2.txt');
+
+    vi.useRealTimers();
+  });
+
+  it('fires onDidChange only once when adding an existing file', () => {
+    const manager = new RecentFilesManager(context);
+    const uri = vscode.Uri.file('/test/file1.txt');
+    manager.add(uri);
+
+    const spy = vi.spyOn(manager['onDidChangeEmitter'], 'fire');
+    manager.add(uri);
+    expect(spy).toHaveBeenCalledTimes(1);
+  });
+
+  it('updates the file when it is renamed', () => {
+    const manager = new RecentFilesManager(context);
+    const oldUri = vscode.Uri.file('/test/file1.txt');
+    const newUri = vscode.Uri.file('/test/file2.txt');
+    manager.add(oldUri);
+    expect(manager.recentFiles).toHaveLength(1);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file1.txt');
+
+    // Simulate renaming the file
+    const renameHandler = vi.mocked(vscode.workspace.onDidRenameFiles).mock
+      .calls[0][0];
+    renameHandler({ files: [{ oldUri, newUri }] });
+
+    expect(manager.recentFiles).toHaveLength(1);
+    expect(manager.recentFiles[0].filePath).toBe('/test/file2.txt');
+  });
+});

packages/vscode-ide-companion/src/recent-files-manager.ts

@@ -0,0 +1,92 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as vscode from 'vscode';
+
+export const MAX_FILES = 10;
+export const MAX_FILE_AGE_MINUTES = 5;
+
+interface RecentFile {
+  uri: vscode.Uri;
+  timestamp: number;
+}
+
+/**
+ * Keeps track of the 10 most recently-opened files
+ * opened less than 5 ago. If a file is closed or deleted,
+ * it will be removed. If the length is maxxed out,
+ * the now-removed file will not be replaced by an older file.
+ */
+export class RecentFilesManager {
+  private readonly files: RecentFile[] = [];
+  private readonly onDidChangeEmitter = new vscode.EventEmitter<void>();
+  readonly onDidChange = this.onDidChangeEmitter.event;
+
+  constructor(private readonly context: vscode.ExtensionContext) {
+    const editorWatcher = vscode.window.onDidChangeActiveTextEditor(
+      (editor) => {
+        if (editor) {
+          this.add(editor.document.uri);
+        }
+      },
+    );
+    const fileWatcher = vscode.workspace.onDidDeleteFiles((event) => {
+      for (const uri of event.files) {
+        this.remove(uri);
+      }
+    });
+    const closeWatcher = vscode.workspace.onDidCloseTextDocument((document) => {
+      this.remove(document.uri);
+    });
+    const renameWatcher = vscode.workspace.onDidRenameFiles((event) => {
+      for (const { oldUri, newUri } of event.files) {
+        this.remove(oldUri, false);
+        this.add(newUri);
+      }
+    });
+    context.subscriptions.push(
+      editorWatcher,
+      fileWatcher,
+      closeWatcher,
+      renameWatcher,
+    );
+  }
+
+  private remove(uri: vscode.Uri, fireEvent = true) {
+    const index = this.files.findIndex(
+      (file) => file.uri.fsPath === uri.fsPath,
+    );
+    if (index !== -1) {
+      this.files.splice(index, 1);
+      if (fireEvent) {
+        this.onDidChangeEmitter.fire();
+      }
+    }
+  }
+
+  add(uri: vscode.Uri) {
+    // Remove if it already exists to avoid duplicates and move it to the top.
+    this.remove(uri, false);
+
+    this.files.unshift({ uri, timestamp: Date.now() });
+
+    if (this.files.length > MAX_FILES) {
+      this.files.pop();
+    }
+    this.onDidChangeEmitter.fire();
+  }
+
+  get recentFiles(): Array<{ filePath: string; timestamp: number }> {
+    const now = Date.now();
+    const maxAgeInMs = MAX_FILE_AGE_MINUTES * 60 * 1000;
+    return this.files
+      .filter((file) => now - file.timestamp < maxAgeInMs)
+      .map((file) => ({
+        filePath: file.uri.fsPath,
+        timestamp: file.timestamp,
+      }));
+  }
+}

packages/vscode-ide-companion/tsconfig.json

@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
-    "module": "Node16",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
     "target": "ES2022",
     "lib": ["ES2022", "dom"],
     "sourceMap": true,