Debugg AI — MCP Server
AI-powered browser testing via the Model Context Protocol. Point it at any URL (or localhost) and describe what to test — an AI agent browses your app and returns pass/fail with screenshots.
Setup
Requires Node.js 20.20.0 or later (transitive requirement from posthog-node@^5.26.0).
Testing http://localhost:... URLs requires the caddy binary — check_app_in_browser,
probe_page, and trigger_crawl tunnel localhost targets through a local Caddy reverse proxy.
This installs automatically: the @radically-straightforward/caddy npm dependency downloads a
pinned Caddy release for your platform during npm install/npx — nothing to install yourself in
the normal case. It is now the only binary this package downloads; the tunnel client itself is
pure TypeScript — it replaced the ngrok package, which fetched the ngrok agent.
If that download never ran (npm install --ignore-scripts, an offline/air-gapped install), point CADDY_BIN at
your own install (brew install caddy / apt install caddy / see
caddyserver.com/docs/install) — missing it surfaces as a
clear error on the first localhost-URL call, not a silent hang. Public-URL calls, every
non-browser tool, and test_suite {action:"run"} (which uses its own dedicated tunnel and
bypasses Caddy entirely) don't need it either way.
