playwright_evaluate
Execute JavaScript in a browser console to interact with web pages or automate tasks directly from the Playwright MCP Server environment.
Instructions
Execute JavaScript in the browser console
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| script | Yes | JavaScript code to execute |
Implementation Reference
- src/tools/browser/interaction.ts:90-113 (handler)The EvaluateTool class provides the core handler logic for 'playwright_evaluate', executing the provided JavaScript script using page.evaluate() and formatting the result for response.
export class EvaluateTool extends BrowserToolBase { /** * Execute the evaluate tool */ async execute(args: any, context: ToolContext): Promise<ToolResponse> { return this.safeExecute(context, async (page) => { const result = await page.evaluate(args.script); // Convert result to string for display let resultStr: string; try { resultStr = JSON.stringify(result, null, 2); } catch (error) { resultStr = String(result); } return createSuccessResponse([ `Executed JavaScript:`, `${args.script}`, `Result:`, `${resultStr}` ]); }); } - src/tools.ts:172-181 (schema)The input schema definition for the 'playwright_evaluate' tool, specifying the 'script' parameter.
name: "playwright_evaluate", description: "Execute JavaScript in the browser console", inputSchema: { type: "object", properties: { script: { type: "string", description: "JavaScript code to execute" }, }, required: ["script"], }, }, - src/toolHandler.ts:483-484 (registration)Registration and dispatching of 'playwright_evaluate' tool call to the EvaluateTool instance in the main tool handler switch statement.
case "playwright_evaluate": return await evaluateTool.execute(args, context); - src/toolHandler.ts:295-295 (registration)Instantiation of the EvaluateTool instance used for handling 'playwright_evaluate' tool calls.
if (!evaluateTool) evaluateTool = new EvaluateTool(server); - src/tools.ts:4-402 (registration)The 'playwright_evaluate' tool is registered in the createToolDefinitions() function which returns the array of all MCP tool definitions.
export function createToolDefinitions() { return [ // Codegen tools { name: "start_codegen_session", description: "Start a new code generation session to record Playwright actions", inputSchema: { type: "object", properties: { options: { type: "object", description: "Code generation options", properties: { outputPath: { type: "string", description: "Directory path where generated tests will be saved (use absolute path)" }, testNamePrefix: { type: "string", description: "Prefix to use for generated test names (default: 'GeneratedTest')" }, includeComments: { type: "boolean", description: "Whether to include descriptive comments in generated tests" } }, required: ["outputPath"] } }, required: ["options"] } }, { name: "end_codegen_session", description: "End a code generation session and generate the test file", inputSchema: { type: "object", properties: { sessionId: { type: "string", description: "ID of the session to end" } }, required: ["sessionId"] } }, { name: "get_codegen_session", description: "Get information about a code generation session", inputSchema: { type: "object", properties: { sessionId: { type: "string", description: "ID of the session to retrieve" } }, required: ["sessionId"] } }, { name: "clear_codegen_session", description: "Clear a code generation session without generating a test", inputSchema: { type: "object", properties: { sessionId: { type: "string", description: "ID of the session to clear" } }, required: ["sessionId"] } }, { name: "playwright_navigate", description: "Navigate to a URL", inputSchema: { type: "object", properties: { url: { type: "string", description: "URL to navigate to the website specified" }, browserType: { type: "string", description: "Browser type to use (chromium, firefox, webkit). Defaults to chromium", enum: ["chromium", "firefox", "webkit"] }, width: { type: "number", description: "Viewport width in pixels (default: 1280)" }, height: { type: "number", description: "Viewport height in pixels (default: 720)" }, timeout: { type: "number", description: "Navigation timeout in milliseconds" }, waitUntil: { type: "string", description: "Navigation wait condition" }, headless: { type: "boolean", description: "Run browser in headless mode (default: false)" } }, required: ["url"], }, }, { name: "playwright_screenshot", description: "Take a screenshot of the current page or a specific element", inputSchema: { type: "object", properties: { name: { type: "string", description: "Name for the screenshot" }, selector: { type: "string", description: "CSS selector for element to screenshot" }, width: { type: "number", description: "Width in pixels (default: 800)" }, height: { type: "number", description: "Height in pixels (default: 600)" }, storeBase64: { type: "boolean", description: "Store screenshot in base64 format (default: true)" }, fullPage: { type: "boolean", description: "Store screenshot of the entire page (default: false)" }, savePng: { type: "boolean", description: "Save screenshot as PNG file (default: false)" }, downloadsDir: { type: "string", description: "Custom downloads directory path (default: user's Downloads folder)" }, }, required: ["name"], }, }, { name: "playwright_click", description: "Click an element on the page", inputSchema: { type: "object", properties: { selector: { type: "string", description: "CSS selector for the element to click" }, }, required: ["selector"], }, }, { name: "playwright_iframe_click", description: "Click an element in an iframe on the page", inputSchema: { type: "object", properties: { iframeSelector: { type: "string", description: "CSS selector for the iframe containing the element to click" }, selector: { type: "string", description: "CSS selector for the element to click" }, }, required: ["iframeSelector", "selector"], }, }, { name: "playwright_fill", description: "fill out an input field", inputSchema: { type: "object", properties: { selector: { type: "string", description: "CSS selector for input field" }, value: { type: "string", description: "Value to fill" }, }, required: ["selector", "value"], }, }, { name: "playwright_select", description: "Select an element on the page with Select tag", inputSchema: { type: "object", properties: { selector: { type: "string", description: "CSS selector for element to select" }, value: { type: "string", description: "Value to select" }, }, required: ["selector", "value"], }, }, { name: "playwright_hover", description: "Hover an element on the page", inputSchema: { type: "object", properties: { selector: { type: "string", description: "CSS selector for element to hover" }, }, required: ["selector"], }, }, { name: "playwright_evaluate", description: "Execute JavaScript in the browser console", inputSchema: { type: "object", properties: { script: { type: "string", description: "JavaScript code to execute" }, }, required: ["script"], }, }, { name: "playwright_console_logs", description: "Retrieve console logs from the browser with filtering options", inputSchema: { type: "object", properties: { type: { type: "string", description: "Type of logs to retrieve (all, error, warning, log, info, debug)", enum: ["all", "error", "warning", "log", "info", "debug"] }, search: { type: "string", description: "Text to search for in logs (handles text with square brackets)" }, limit: { type: "number", description: "Maximum number of logs to return" }, clear: { type: "boolean", description: "Whether to clear logs after retrieval (default: false)" } }, required: [], }, }, { name: "playwright_close", description: "Close the browser and release all resources", inputSchema: { type: "object", properties: {}, required: [], }, }, { name: "playwright_get", description: "Perform an HTTP GET request", inputSchema: { type: "object", properties: { url: { type: "string", description: "URL to perform GET operation" } }, required: ["url"], }, }, { name: "playwright_post", description: "Perform an HTTP POST request", inputSchema: { type: "object", properties: { url: { type: "string", description: "URL to perform POST operation" }, value: { type: "string", description: "Data to post in the body" }, token: { type: "string", description: "Bearer token for authorization" }, headers: { type: "object", description: "Additional headers to include in the request", additionalProperties: { type: "string" } } }, required: ["url", "value"], }, }, { name: "playwright_put", description: "Perform an HTTP PUT request", inputSchema: { type: "object", properties: { url: { type: "string", description: "URL to perform PUT operation" }, value: { type: "string", description: "Data to PUT in the body" }, }, required: ["url", "value"], }, }, { name: "playwright_patch", description: "Perform an HTTP PATCH request", inputSchema: { type: "object", properties: { url: { type: "string", description: "URL to perform PUT operation" }, value: { type: "string", description: "Data to PATCH in the body" }, }, required: ["url", "value"], }, }, { name: "playwright_delete", description: "Perform an HTTP DELETE request", inputSchema: { type: "object", properties: { url: { type: "string", description: "URL to perform DELETE operation" } }, required: ["url"], }, }, { 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"], }, }, { 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"], }, }, { name: "playwright_custom_user_agent", description: "Set a custom User Agent for the browser", inputSchema: { type: "object", properties: { userAgent: { type: "string", description: "Custom User Agent for the Playwright browser instance" } }, required: ["userAgent"], }, }, { name: "playwright_get_visible_text", description: "Get the visible text content of the current page", inputSchema: { type: "object", properties: {}, required: [], }, }, { name: "playwright_get_visible_html", description: "Get the HTML content of the current page", inputSchema: { type: "object", properties: {}, required: [], }, }, { name: "playwright_go_back", description: "Navigate back in browser history", inputSchema: { type: "object", properties: {}, required: [], }, }, { name: "playwright_go_forward", description: "Navigate forward in browser history", inputSchema: { type: "object", properties: {}, required: [], }, }, { name: "playwright_drag", description: "Drag an element to a target location", inputSchema: { type: "object", properties: { sourceSelector: { type: "string", description: "CSS selector for the element to drag" }, targetSelector: { type: "string", description: "CSS selector for the target location" } }, required: ["sourceSelector", "targetSelector"], }, }, { name: "playwright_press_key", description: "Press a keyboard key", inputSchema: { type: "object", properties: { key: { type: "string", description: "Key to press (e.g. 'Enter', 'ArrowDown', 'a')" }, selector: { type: "string", description: "Optional CSS selector to focus before pressing key" } }, required: ["key"], }, }, { name: "playwright_save_as_pdf", description: "Save the current page as a PDF file", inputSchema: { type: "object", properties: { outputPath: { type: "string", description: "Directory path where PDF will be saved" }, filename: { type: "string", description: "Name of the PDF file (default: page.pdf)" }, format: { type: "string", description: "Page format (e.g. 'A4', 'Letter')" }, printBackground: { type: "boolean", description: "Whether to print background graphics" }, margin: { type: "object", description: "Page margins", properties: { top: { type: "string" }, right: { type: "string" }, bottom: { type: "string" }, left: { type: "string" } } } }, required: ["outputPath"], }, }, ] as const satisfies Tool[]; }