feat: browser_file_download

README.md

@@ -405,6 +405,13 @@ http.createServer(async (req, res) => {
 
 <!-- NOTE: This has been generated via update-readme.js -->
 
+- **browser_file_download**
+  - Description: Accept file downloads. Only use this if there is a download modal visible.
+  - Parameters:
+    - `filenames` (array): The filenames to accept. All other files will be canceled.
+
+<!-- NOTE: This has been generated via update-readme.js -->
+
 - **browser_pdf_save**
   - Description: Save page as PDF
   - Parameters: None

src/context.ts

@@ -64,6 +64,10 @@ export class Context {
     this._modalStates = this._modalStates.filter(state => state !== modalState);
   }
 
+  hasModalState(type: ModalState['type']) {
+    return this._modalStates.some(state => state.type === type);
+  }
+
   modalStatesMarkdown(): string[] {
     const result: string[] = ['### Modal state'];
     for (const state of this._modalStates) {
@@ -340,6 +344,13 @@ export class Tab {
         fileChooser: chooser,
       }, this);
     });
+    page.on('download', download => {
+      this.context.setModalState({
+        type: 'download',
+        description: `Download (${download.suggestedFilename()})`,
+        download,
+      }, this);
+    });
     page.on('dialog', dialog => this.context.dialogShown(this, dialog));
     page.setDefaultNavigationTimeout(60000);
     page.setDefaultTimeout(5000);
@@ -356,7 +367,13 @@ export class Tab {
   }
 
   async navigate(url: string) {
-    await this.page.goto(url, { waitUntil: 'domcontentloaded' });
+    try {
+      await this.page.goto(url, { waitUntil: 'domcontentloaded' });
+    } catch (error) {
+      if (error instanceof Error && error.message.includes('net::ERR_ABORTED') && this.context.hasModalState('download'))
+        return;
+    }
+
     // Cap load event to 5 seconds, the page is operational at this point.
     await this.page.waitForLoadState('load', { timeout: 5000 }).catch(() => {});
   }

src/tools/files.ts

@@ -15,9 +15,13 @@
  */
 
 import { z } from 'zod';
-import { defineTool, type ToolFactory } from './tool';
+import os from 'os';
+import path from 'path';
 
-const uploadFile: ToolFactory = captureSnapshot => defineTool({
+import { defineTool, DownloadModalState, type ToolFactory } from './tool';
+import { sanitizeForFilePath } from './utils';
+
+const uploadFile: ToolFactory = captureSnapshot => ({
   capability: 'files',
 
   schema: {
@@ -52,6 +56,58 @@ const uploadFile: ToolFactory = captureSnapshot => defineTool({
   clearsModalState: 'fileChooser',
 });
 
+const downloadFile = defineTool({
+  capability: 'files',
+
+  schema: {
+    name: 'browser_file_download',
+    description: 'Accept file downloads. Only use this if there is a download modal visible.',
+    inputSchema: z.object({
+      filenames: z.array(z.string()).describe('The filenames to accept. All other files will be canceled.'),
+    }),
+  },
+
+  handle: async (context, params) => {
+    const modals = context.modalStates().filter(state => state.type === 'download');
+    if (!modals.length)
+      throw new Error('No download modal visible');
+
+    const accepted = new Set<DownloadModalState>();
+    for (const filename of params.filenames) {
+      const download = modals.find(modal => modal.download.suggestedFilename() === filename);
+      if (!download)
+        throw new Error(`No download modal visible for file ${filename}`);
+      accepted.add(download);
+    }
+
+    return {
+      code: [`// <internal code to accept and cancel files>`],
+      action: async () => {
+        const text: string[] = [];
+        await Promise.all(modals.map(async modal => {
+          context.clearModalState(modal);
+
+          if (!accepted.has(modal))
+            return modal.download.cancel();
+
+          const filePath = path.join(os.tmpdir(), sanitizeForFilePath(`download-${new Date().toISOString()}`), modal.download.suggestedFilename());
+          try {
+            await modal.download.saveAs(filePath);
+            text.push(`Downloaded ${modal.download.suggestedFilename()} to ${filePath}`);
+          } catch {
+            text.push(`Failed to download ${modal.download.suggestedFilename()}`);
+          }
+        }));
+        return { content: [{ type: 'text', text: text.join('\n') }] };
+      },
+      captureSnapshot: false,
+      waitForNetwork: true,
+    };
+  },
+  clearsModalState: 'download',
+});
+
 export default (captureSnapshot: boolean) => [
   uploadFile(captureSnapshot),
+  downloadFile,
 ];

src/tools/tool.ts

@@ -34,13 +34,19 @@ export type FileUploadModalState = {
   fileChooser: playwright.FileChooser;
 };
 
+export type DownloadModalState = {
+  type: 'download';
+  description: string;
+  download: playwright.Download;
+};
+
 export type DialogModalState = {
   type: 'dialog';
   description: string;
   dialog: playwright.Dialog;
 };
 
-export type ModalState = FileUploadModalState | DialogModalState;
+export type ModalState = FileUploadModalState | DialogModalState | DownloadModalState;
 
 export type ToolActionResult = { content?: (ImageContent | TextContent)[] } | undefined | void;
 

tests/capabilities.spec.ts

@@ -22,6 +22,7 @@ test('test snapshot tool list', async ({ client }) => {
     'browser_click',
     'browser_console_messages',
     'browser_drag',
+    'browser_file_download',
     'browser_file_upload',
     'browser_handle_dialog',
     'browser_hover',
@@ -51,6 +52,7 @@ test('test vision tool list', async ({ visionClient }) => {
   expect(new Set(visionTools.map(t => t.name))).toEqual(new Set([
     'browser_close',
     'browser_console_messages',
+    'browser_file_download',
     'browser_file_upload',
     'browser_handle_dialog',
     'browser_install',

tests/files.spec.ts

@@ -85,3 +85,69 @@ test('browser_file_upload', async ({ client }) => {
 - [File chooser]: can be handled by the "browser_file_upload" tool`);
   }
 });
+
+test.describe('browser_file_download', () => {
+  test('after clicking on download link', async ({ client, mcpBrowser }) => {
+    test.skip(mcpBrowser === 'webkit' && process.platform === 'linux');
+
+    expect(await client.callTool({
+      name: 'browser_navigate',
+      arguments: {
+        url: 'data:text/html,<a href="data:text/plain,Hello world!" download="test.txt">Download</a>',
+      },
+    })).toContainTextContent('- link "Download" [ref=s1e3]');
+
+    expect(await client.callTool({
+      name: 'browser_click',
+      arguments: {
+        element: 'Download link',
+        ref: 's1e3',
+      },
+    })).toContainTextContent(`
+### Modal state
+- [Download (test.txt)]: can be handled by the "browser_file_download" tool`);
+
+    expect(await client.callTool({
+      name: 'browser_snapshot',
+      arguments: {},
+    })).toContainTextContent(`
+Tool "browser_snapshot" does not handle the modal state.
+### Modal state
+- [Download (test.txt)]: can be handled by the "browser_file_download" tool`.trim());
+
+    expect(await client.callTool({
+      name: 'browser_file_download',
+      arguments: {
+        filenames: ['wrong_file.txt'],
+      },
+    })).toContainTextContent(`Error: No download modal visible for file wrong_file.txt`);
+
+    expect(await client.callTool({
+      name: 'browser_file_download',
+      arguments: {
+        filenames: ['test.txt'],
+      },
+    })).toContainTextContent([`Downloaded test.txt to`, '// <internal code to accept and cancel files>']);
+  });
+
+  test('navigating to downloading link', async ({ client, server, mcpBrowser }) => {
+    test.skip(mcpBrowser === 'msedge' || mcpBrowser === 'chrome');
+
+    server.route('/', (req, res) => {
+      res.setHeader('Content-Disposition', 'attachment; filename="test.txt"');
+      res.end('Hello world!');
+    });
+    expect(await client.callTool({
+      name: 'browser_navigate',
+      arguments: {
+        url: server.PREFIX,
+      },
+    })).toContainTextContent('### Modal state\n- [Download (test.txt)]');
+    expect(await client.callTool({
+      name: 'browser_file_download',
+      arguments: {
+        filenames: ['test.txt'],
+      },
+    })).toContainTextContent([`Downloaded test.txt to`, '// <internal code to accept and cancel files>\n```\n\n- Page URL: about:blank']);
+  });
+});