diff --git a/README.md b/README.md
index 2da229c..7f61ba5 100644
--- a/README.md
+++ b/README.md
@@ -3,9 +3,10 @@
 
 Setup: `npm install && npx playwright install` (downloads {chromium, firefox, webkit} (742 MB) to cache in home ([doc](https://playwright.dev/docs/browsers#managing-browser-binaries))).
 
-Run `npm login` which opens a browser where you can login. When closing the browser, it writes a file `auth.json` containing cookies that should keep you logged in for some time.
+Run `npm login` which opens a browser where you can login. When closing the browser, it writes a file `auth.json` containing cookies that should keep you logged in for some time (`expires` in a month?).
 
 Then use `npm start` to run Chrome in headless mode to claim the current free game.
+If something goes wrong, try `npm start -- --debug` to investigate.
 
 ## log
 
@@ -22,3 +23,7 @@ Also, solving via [2captcha](https://2captcha.com?from=13225256) is a paid servi
 
 Added [main.stealth.js](https://github.com/vogler/epicgames-claimer/commit/64d0ba8ce71baec3947d1b64acd567befcb39340#diff-f70d3bd29df4a343f11062a97063953173491ce30fe34f69a0fc52517adbf342) which uses the stealth plugin without `playwright-extra` wrapper but up-to-date `playwright` (from [comment](https://github.com/berstend/puppeteer-extra/issues/454#issuecomment-917437212)).
 The listed evasions are enough to not show an hcaptcha. Script claimed game successfully in headful mode.
+
+Removed `main.captcha.js`.
+Using Playwright Test (`main.spec.ts`) instead of Library (`main.stealth.js`) has the advantage of free CLI like `--debug` and `--timeout`.
+TODO: check if stealth plugin can be setup with `contextOptions` ([doc](https://playwright.dev/docs/test-configuration#more-browser-and-context-options)).
diff --git a/main.stealth.js b/main.stealth.js
index 8a1a68f..6144f77 100644
--- a/main.stealth.js
+++ b/main.stealth.js
@@ -5,12 +5,15 @@ if (!existsSync('auth.json')) {
   process.exit(1);
 }
 
+const args = process.argv.slice(2);
+const debug = args.includes('--debug');
+
 const { chromium } = require('playwright'); // stealth plugin needs no outdated playwright-extra
 
 // stealth with playwright: https://github.com/berstend/puppeteer-extra/issues/454#issuecomment-917437212
 const newStealthContext = async (browser, contextOptions = {}) => {
   const originalUserAgent = await (await (await browser.newContext()).newPage()).evaluate(() => navigator.userAgent);
-  console.log('userAgent:', originalUserAgent); // Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/96.0.4664.110 Safari/537.36
+  if (debug) console.log('userAgent:', originalUserAgent); // Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/96.0.4664.110 Safari/537.36
   const context = await browser.newContext({
     ...contextOptions,
     userAgent: originalUserAgent.replace("Headless", ""), // HeadlessChrome -> Chrome
@@ -50,7 +53,7 @@ const newStealthContext = async (browser, contextOptions = {}) => {
 (async () => {
   const browser = await chromium.launch({
     channel: 'chrome',
-    headless: false,
+    headless: !debug,
   });
   /** @type {import('playwright').BrowserContext} */
   const context = await newStealthContext(browser, {