playwright_expect_response
Initiate a wait operation for an HTTP response matching a specified URL pattern without completing the wait. Use this tool to prepare response assertions in browser automation workflows.
Instructions
Ask Playwright to start waiting for a HTTP response. This tool initiates the wait operation but does not wait for its completion.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Unique & arbitrary identifier to be used for retrieving this response later with `Playwright_assert_response`. | |
| url | Yes | URL pattern to match in the response. |
Implementation Reference
- src/tools/browser/response.ts:21-37 (handler)The main handler function for the 'playwright_expect_response' tool. It sets up a Playwright page.waitForResponse promise for the given URL pattern and stores it in a global map using the provided ID.
export class ExpectResponseTool extends BrowserToolBase { /** * Execute the expect response tool */ async execute(args: ExpectResponseArgs, context: ToolContext): Promise<ToolResponse> { return this.safeExecute(context, async (page) => { if (!args.id || !args.url) { return createErrorResponse("Missing required parameters: id and url must be provided"); } const responsePromise = page.waitForResponse(args.url); responsePromises.set(args.id, responsePromise); return createSuccessResponse(`Started waiting for response with ID ${args.id}`); }); } } - src/tools.ts:307-318 (schema)The input schema definition and tool metadata (name, description) for registration with the MCP server.
{ name: "playwright_expect_response", description: "Ask Playwright to start waiting for a HTTP response. This tool initiates the wait operation but does not wait for its completion.", inputSchema: { type: "object", properties: { id: { type: "string", description: "Unique & arbitrary identifier to be used for retrieving this response later with `Playwright_assert_response`." }, url: { type: "string", description: "URL pattern to match in the response." } }, required: ["id", "url"], }, }, - src/toolHandler.ts:508-509 (registration)The dispatch case in the main tool handler that routes calls to the ExpectResponseTool instance.
case "playwright_expect_response": return await expectResponseTool.execute(args, context); - src/toolHandler.ts:329-329 (registration)Instantiation of the ExpectResponseTool class instance used for handling tool calls.
if (!expectResponseTool) expectResponseTool = new ExpectResponseTool(server); - src/tools/browser/response.ts:6-6 (helper)Global map storing pending response promises keyed by ID, shared between expect and assert tools.
const responsePromises = new Map<string, Promise<Response>>();