CDP probe scripts validate profile launches, navigation, and extraction paths against a running Koko server. They are the fastest way to debug regressions without full test suites.

Profile CDP smoke

npm run test:profile -- --profile chrome-macos-catalina

Runs scripts/cdp-profile-probe.mjs — navigates, extracts, and verifies CDP health for a profile.

Probe timeout rule

All scripts/cdp-*.mjs probes enforce a 20 second maximum (--max-sec, default 20):

>20s = hang → SIGKILL Koko, exit code 3, [HANG] marker
No retry on the same hung command
Helper: scripts/lib/cdp-probe-budget.mjs

Manual CDP inspection

# Start server
zig build run -- serve --port 9222

# Check targets
curl http://127.0.0.1:9222/json/version
curl http://127.0.0.1:9222/json/list

Google offline fixtures

Use code-check/tmp/google-serp-skeleton.html for offline Google SERP probes — not live google.com in CI.

Connect with Playwright CDP

For comparison debugging, attach Playwright directly:

import { chromium } from "playwright";
const browser = await chromium.connectOverCDP("http://127.0.0.1:9222");

When probes hang

Check if Koko process is alive (/json/version)
Kill stale koko serve processes
Re-run with --max-sec 20 — do not increase timeout to mask hangs
File a bug with probe output and profile ID