/**
* @license
* Copyright 2025 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
import {zod} from '../third_party/index.js';
import type {JSHandle} from '../third_party/index.js';
import {ToolCategory} from './categories.js';
import {defineTool} from './ToolDefinition.js';
// Default script evaluation timeout in milliseconds (30 seconds)
const DEFAULT_SCRIPT_TIMEOUT = 30000;
function withTimeout<T>(
promise: Promise<T>,
ms: number,
message: string,
): Promise<T> {
return Promise.race([
promise,
new Promise<T>((_, reject) => {
setTimeout(() => reject(new Error(message)), ms);
}),
]);
}
export const evaluateScript = defineTool({
name: 'evaluate_script',
description: `Evaluate a JavaScript function inside the currently selected page. Returns the response as JSON
so returned values have to JSON-serializable.`,
annotations: {
category: ToolCategory.DEBUGGING,
readOnlyHint: false,
},
schema: {
function: zod.string().describe(
`A JavaScript function declaration to be executed by the tool in the currently selected page.
Example without arguments: \`() => {
return document.title
}\` or \`async () => {
return await fetch("example.com")
}\`.
Example with arguments: \`(el) => {
return el.innerText;
}\`
`,
),
},
handler: async (request, response, context) => {
let fn: JSHandle<unknown> | undefined;
try {
const page = context.getSelectedPage();
fn = await withTimeout(
page.evaluateHandle(`(${request.params.function})`),
DEFAULT_SCRIPT_TIMEOUT,
'Script evaluation timed out',
);
await context.waitForEventsAfterAction(async () => {
const result = await withTimeout(
page.evaluate(async fn => {
// @ts-expect-error no types.
return JSON.stringify(await fn());
}, fn),
DEFAULT_SCRIPT_TIMEOUT,
'Script execution timed out',
);
response.appendResponseLine('Script ran on page and returned:');
response.appendResponseLine('```json');
response.appendResponseLine(`${result}`);
response.appendResponseLine('```');
});
} finally {
if (fn) {
void fn.dispose();
}
}
},
});
