playwright-stealth-verify

Verify an automation harness against itself

A test browser that quietly looks wrong is a test suite that quietly gets challenged. liarjs answers one question about a harness: does its JavaScript story agree with itself and with what the network layer saw? It measures; it does not modify the browser and ships no evasions or profiles.

Node 22 or newer. Zero runtime dependencies, so it adds nothing to an existing Playwright or Puppeteer install.

Against a Page you already have

checkPage works with any object exposing evaluate(expression: string). Playwright and Puppeteer Page objects both qualify, so the harness under test is the harness being measured, with its real launch flags, real plugins and real proxy in place.

import { checkPage } from 'liarjs';

const result = await checkPage(page);

expect(result.score).toBeGreaterThanOrEqual(85);

// Or assert on specific ids rather than a single number:
const critical = result.checks.filter((c) => c.status === 'bad');
expect(critical, JSON.stringify(critical, null, 2)).toHaveLength(0);

ScanResult is { score, label, checks[], client, server, meta }: client is the raw fingerprint, server the raw edge view, meta.schema the payload version.

Install as a dev dependency so the version is pinned in the lockfile:

npm install --save-dev liarjs

Against a browser started outside the test process

npx [email protected] --cdp http://127.0.0.1:9222

Use this when the browser is already running and is itself the subject of the question, for example a Chromium build with local patches:

./chrome --remote-debugging-port=9222 &
npx [email protected] --cdp http://127.0.0.1:9222

Attaching drives a session the user owns. Confirm the endpoint with the user first, and prefer the default (npx [email protected], which launches its own throwaway profile in a temp directory and deletes it afterwards) whenever the question is about a launch configuration rather than about one specific running browser.