playwright_assert_response

Validate HTTP responses in browser automation tests by checking response body content against expected values after initiating a wait operation.

Instructions

Wait for and validate a previously initiated HTTP response wait operation.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`id`	Yes	Identifier of the HTTP response initially expected using `Playwright_expect_response`.
`value`	No	Data to expect in the body of the HTTP response. If provided, the assertion will fail if this value is not found in the response body.

Implementation Reference

src/tools/browser/response.ts:42-86 (handler)

The AssertResponseTool class implements the core logic for the 'playwright_assert_response' tool. It retrieves a previously set response promise, awaits the response, parses the JSON body, optionally asserts if a specific value is present, and returns detailed success or error information.

export class AssertResponseTool extends BrowserToolBase {
  /**
   * Execute the assert response tool
   */
  async execute(args: AssertResponseArgs, context: ToolContext): Promise<ToolResponse> {
    return this.safeExecute(context, async () => {
      if (!args.id) {
        return createErrorResponse("Missing required parameter: id must be provided");
      }

      const responsePromise = responsePromises.get(args.id);
      if (!responsePromise) {
        return createErrorResponse(`No response wait operation found with ID: ${args.id}`);
      }

      try {
        const response = await responsePromise;
        const body = await response.json();

        if (args.value) {
          const bodyStr = JSON.stringify(body);
          if (!bodyStr.includes(args.value)) {
            const messages = [
              `Response body does not contain expected value: ${args.value}`,
              `Actual body: ${bodyStr}`,
            ];
            return createErrorResponse(messages.join("\n"));
          }
        }

        const messages = [
          `Response assertion for ID ${args.id} successful`,
          `URL: ${response.url()}`,
          `Status: ${response.status()}`,
          `Body: ${JSON.stringify(body, null, 2)}`,
        ];
        return createSuccessResponse(messages.join("\n"));
      } catch (error) {
        return createErrorResponse(`Failed to assert response: ${(error as Error).message}`);
      } finally {
        responsePromises.delete(args.id);
      }
    });
  }
}

src/tools.ts:354-372 (schema)

The input schema definition for the 'playwright_assert_response' tool, specifying parameters 'id' (required) and optional 'value' for response body assertion.

{
  name: "playwright_assert_response",
  description: "Wait for and validate a previously initiated HTTP response wait operation.",
  inputSchema: {
    type: "object",
    properties: {
      id: {
        type: "string",
        description: "Identifier of the HTTP response initially expected using `Playwright_expect_response`.",
      },
      value: {
        type: "string",
        description:
          "Data to expect in the body of the HTTP response. If provided, the assertion will fail if this value is not found in the response body.",
      },
    },
    required: ["id"],
  },
},

src/toolHandler.ts:612-613 (registration)
Registration of the 'playwright_assert_response' tool in the main tool dispatch switch statement, delegating execution to the AssertResponseTool instance.
```
case "playwright_assert_response":
  return await assertResponseTool.execute(args, context);
```
src/tools.ts:506-506 (registration)
The tool name is listed in the BROWSER_TOOLS array, used for conditional browser launching.
```
"playwright_assert_response",
```

mcp-playwright