browser_evaluate
Execute JavaScript code directly in the browser console to interact with web pages and automate browser tasks.
Instructions
Execute JavaScript in the browser console
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| script | Yes | JavaScript code to execute |
Implementation Reference
- index.ts:521-561 (handler)Handler function for browser_evaluate tool: executes the provided JavaScript script in the browser context using page.evaluate, captures console logs, and returns the result or error.
case ToolName.BrowserEvaluate: try { const result = await page.evaluate((script) => { const logs: string[] = []; const originalConsole = { ...console }; ['log', 'info', 'warn', 'error'].forEach(method => { (console as any)[method] = (...args: any[]) => { logs.push(`[${method}] ${args.join(' ')}`); (originalConsole as any)[method](...args); }; }); try { const result = eval(script); Object.assign(console, originalConsole); return { result, logs }; } catch (error) { Object.assign(console, originalConsole); throw error; } }, args.script); return { content: [ { type: "text", text: `Execution result:\n${JSON.stringify(result.result, null, 2)}\n\nConsole output:\n${result.logs.join('\n')}`, }, ], isError: false, }; } catch (error) { return { content: [{ type: "text", text: `Script execution failed: ${(error as Error).message}`, }], isError: true, }; } - index.ts:141-151 (registration)Tool registration in the TOOLS array, including name, description, and input schema. This array is served via ListToolsRequestSchema.
{ name: ToolName.BrowserEvaluate, description: "Execute JavaScript in the browser console", inputSchema: { type: "object", properties: { script: { type: "string", description: "JavaScript code to execute" }, }, required: ["script"], }, }, - index.ts:144-150 (schema)Input schema definition for the browser_evaluate tool, specifying the 'script' parameter.
inputSchema: { type: "object", properties: { script: { type: "string", description: "JavaScript code to execute" }, }, required: ["script"], }, - index.ts:22-33 (helper)Enum defining ToolName.BrowserEvaluate = "browser_evaluate", used throughout for tool identification.
enum ToolName { BrowserNavigate = "browser_navigate", BrowserScreenshot = "browser_screenshot", BrowserClick = "browser_click", BrowserClickText = "browser_click_text", BrowserFill = "browser_fill", BrowserSelect = "browser_select", BrowserSelectText = "browser_select_text", BrowserHover = "browser_hover", BrowserHoverText = "browser_hover_text", BrowserEvaluate = "browser_evaluate" }