chore: implement trigger extension action

.github/workflows/run-tests.yml

@@ -41,6 +41,12 @@ jobs:
         shell: bash
         run: npm ci
 
+      - name: Install Chrome Canary
+        shell: bash
+        run: |
+          CANARY_PATH=$(npx @puppeteer/browsers install chrome@canary --format "{{path}}")
+          echo "CANARY_EXECUTABLE_PATH=$CANARY_PATH" >> $GITHUB_ENV
+
       - name: Build
         run: npm run bundle
         env:

src/McpContext.ts

@@ -919,6 +919,24 @@ export class McpContext implements Context {
     this.#extensionRegistry.remove(id);
   }
 
+  async triggerExtensionAction(id: string): Promise<void> {
+    const page = this.getSelectedPptrPage();
+    // @ts-expect-error internal puppeteer api is needed since we don't have a way to get
+    // a tab id at the moment
+    const theTarget = page._tabId;
+    const session = await this.browser.target().createCDPSession();
+
+    try {
+      // @ts-expect-error triggerAction is not yet available
+      await session.send('Extensions.triggerAction', {
+        id,
+        targetId: theTarget,
+      });
+    } finally {
+      await session.detach();
+    }
+  }
+
   listExtensions(): InstalledExtension[] {
     return this.#extensionRegistry.list();
   }

src/McpResponse.ts

@@ -595,7 +595,7 @@ Call ${handleDialog.name} to handle it before continuing.`);
     }
 
     if (this.#includeExtensionServiceWorkers) {
-      if (!context.getExtensionServiceWorkers().length) {
+      if (context.getExtensionServiceWorkers().length) {
         response.push(`## Extension Service Workers`);
       }
 

src/tools/ToolDefinition.ts

@@ -190,6 +190,7 @@ export type Context = Readonly<{
   ): void;
   installExtension(path: string): Promise<string>;
   uninstallExtension(id: string): Promise<void>;
+  triggerExtensionAction(id: string): Promise<void>;
   listExtensions(): InstalledExtension[];
   getExtension(id: string): InstalledExtension | undefined;
   getSelectedMcpPage(): McpPage;

src/tools/extensions.ts

@@ -85,3 +85,21 @@ export const reloadExtension = defineTool({
     response.appendResponseLine('Extension reloaded.');
   },
 });
+
+export const triggerExtensionAction = defineTool({
+  name: 'trigger_extension_action',
+  description: 'Triggers an action in a Chrome extension.',
+  annotations: {
+    category: ToolCategory.EXTENSIONS,
+    readOnlyHint: false,
+    conditions: [EXTENSIONS_CONDITION],
+  },
+  schema: {
+    id: zod.string().describe('ID of the extension.'),
+  },
+  handler: async (request, response, context) => {
+    const {id} = request.params;
+    await context.triggerExtensionAction(id);
+    response.appendResponseLine(`Extension action triggered. Id: ${id}`);
+  },
+});

tests/tools/extensions.test.ts

@@ -10,29 +10,25 @@ import {afterEach, describe, it} from 'node:test';
 
 import sinon from 'sinon';
 
-import type {McpResponse} from '../../src/McpResponse.js';
+import type {ParsedArguments} from '../../src/cli.js';
 import {
   installExtension,
   uninstallExtension,
   listExtensions,
   reloadExtension,
+  triggerExtensionAction,
 } from '../../src/tools/extensions.js';
-import {withMcpContext} from '../utils.js';
+import {extractExtensionId, withMcpContext} from '../utils.js';
 
+const EXTENSION_WITH_SW_PATH = path.join(
+  import.meta.dirname,
+  '../../../tests/tools/fixtures/extension-sw',
+);
 const EXTENSION_PATH = path.join(
   import.meta.dirname,
   '../../../tests/tools/fixtures/extension',
 );
 
-export function extractId(response: McpResponse) {
-  const responseLine = response.responseLines[0];
-  assert.ok(responseLine, 'Response should not be empty');
-  const match = responseLine.match(/Extension installed\. Id: (.+)/);
-  const extensionId = match ? match[1] : null;
-  assert.ok(extensionId, 'Response should contain a valid key');
-  return extensionId;
-}
-
 describe('extension', () => {
   afterEach(() => {
     sinon.restore();
@@ -47,7 +43,7 @@ describe('extension', () => {
         context,
       );
 
-      const extensionId = extractId(response);
+      const extensionId = extractExtensionId(response);
       const page = context.getSelectedPptrPage();
       await page.goto('chrome://extensions');
 
@@ -102,7 +98,7 @@ describe('extension', () => {
         context,
       );
 
-      const extensionId = extractId(response);
+      const extensionId = extractExtensionId(response);
       const installSpy = sinon.spy(context, 'installExtension');
       response.resetResponseLineForTesting();
 
@@ -128,4 +124,36 @@ describe('extension', () => {
       assert.ok(reinstalled, 'Extension should be present after reload');
     });
   });
+  it('triggers an extension action', async () => {
+    await withMcpContext(
+      async (response, context) => {
+        const extensionId = await context.installExtension(
+          EXTENSION_WITH_SW_PATH,
+        );
+
+        const targetsBefore = context.browser.targets();
+        const pageTargetBefore = targetsBefore.find(
+          t => t.type() === 'page' && t.url().includes(extensionId),
+        );
+        assert.ok(!pageTargetBefore, 'Page should not exist before action');
+
+        await triggerExtensionAction.handler(
+          {params: {id: extensionId}},
+          response,
+          context,
+        );
+
+        const pageTargetAfter = await context.browser.waitForTarget(
+          t => t.type() === 'page' && t.url().includes(extensionId),
+        );
+        assert.ok(pageTargetAfter, 'Page should exist after action');
+      },
+      {
+        executablePath: process.env.CANARY_EXECUTABLE_PATH,
+      },
+      {
+        categoryExtensions: true,
+      } as ParsedArguments,
+    );
+  });
 });

tests/tools/fixtures/extension-sw/sw.js

@@ -1 +1,3 @@
-console.log('Service worker loaded');
+chrome.action.onClicked.addListener(tab => {
+  console.log('Action clicked');
+});

tests/tools/script.test.ts

@@ -12,9 +12,7 @@ import type {ParsedArguments} from '../../src/cli.js';
 import {installExtension} from '../../src/tools/extensions.js';
 import {evaluateScript} from '../../src/tools/script.js';
 import {serverHooks} from '../server.js';
-import {html, withMcpContext} from '../utils.js';
-
-import {extractId} from './extensions.test.js';
+import {extractExtensionId, html, withMcpContext} from '../utils.js';
 
 const EXTENSION_PATH = path.join(
   import.meta.dirname,
@@ -209,7 +207,7 @@ describe('script', () => {
             context,
           );
 
-          const extensionId = extractId(response);
+          const extensionId = extractExtensionId(response);
           const swTarget = await context.browser.waitForTarget(
             t => t.type() === 'service_worker' && t.url().includes(extensionId),
           );

tests/utils.ts

@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import assert from 'node:assert';
+
 import type {CallToolResult} from '@modelcontextprotocol/sdk/types.js';
 import logger from 'debug';
 import type {Browser} from 'puppeteer';
@@ -42,15 +44,29 @@ export function getImageContent(content: CallToolResult['content'][number]): {
   throw new Error(`Expected image content but got ${content.type}`);
 }
 
+export function extractExtensionId(response: McpResponse) {
+  const responseLine = response.responseLines[0];
+  assert.ok(responseLine, 'Response should not be empty');
+  const match = responseLine.match(/Extension installed\. Id: (.+)/);
+  const extensionId = match ? match[1] : null;
+  assert.ok(extensionId, 'Response should contain a valid key');
+  return extensionId;
+}
+
 const browsers = new Map<string, Browser>();
 let context: McpContext | undefined;
 
 export async function withBrowser(
   cb: (browser: Browser, page: Page) => Promise<void>,
-  options: {debug?: boolean; autoOpenDevTools?: boolean} = {},
+  options: {
+    debug?: boolean;
+    autoOpenDevTools?: boolean;
+    executablePath?: string;
+  } = {},
 ) {
   const launchOptions: LaunchOptions = {
-    executablePath: process.env.PUPPETEER_EXECUTABLE_PATH,
+    executablePath:
+      options.executablePath ?? process.env.PUPPETEER_EXECUTABLE_PATH,
     headless: !options.debug,
     defaultViewport: null,
     devtools: options.autoOpenDevTools ?? false,
@@ -85,6 +101,7 @@ export async function withMcpContext(
     debug?: boolean;
     autoOpenDevTools?: boolean;
     performanceCrux?: boolean;
+    executablePath?: string;
   } = {},
   args: ParsedArguments = {} as ParsedArguments,
 ) {