The read-only tools of this host, callable with a URL

8 endpoints. Each is a tool an MCP server here already runs, reachable with query parameters instead of a JSON-RPC session: no account, no key, no handshake, CORS open, cacheable, CC0. The MCP servers are unchanged and share one implementation with these, so a tool cannot answer two different things depending on which door you came through.

curl -s 'https://www.pathwren.workers.dev/tools/whoami?&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/example?&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/verify-crawler?ip=66.249.66.1&ua=Googlebot&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/robots-lint?robots_txt=User-agent%3A%20GPTBot%0ADisallow%3A%20%2F%0ANoindex%3A%20%2Fprivate%0A&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/robots-allowed?robots_txt=User-agent%3A%20*%0ADisallow%3A%20%2F%0AAllow%3A%20%2Fblog%2F%0A&ua=GPTBot&path=/blog/post&path=/private&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/ai-access?robots_txt=User-agent%3A%20GPTBot%0ADisallow%3A%20%2F%0A&path=/&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/classify-ua?ua=Mozilla%2F5.0%20AppleWebKit%2F537.36%20(KHTML%2C%20like%20Gecko%3B%20compatible%3B%20GPTBot%2F1.2%3B%20%2Bhttps%3A%2F%2Fopenai.com%2Fgptbot)&s=client-dossiers'
curl -s 'https://www.pathwren.workers.dev/tools/verification-methods?crawler=claudebot&s=client-dossiers'

Why this exists

In 24 hours, 97 of the 107 clients that touched an MCP or A2A surface on this host only looked — GET, HEAD, OPTIONS, a card fetch, a tool-definition read. The named ones say so themselves: liveness-only, never invokes tools, read-only tool-definition observer. They are crawlers, graders and monitors, and not one of them speaks JSON-RPC over POST. They can all speak GET. That is the whole hypothesis here: the barrier was the protocol, not the interest.

Every endpoint

The rules all of them keep

• No parameters at all → 200 and the endpoint's own specification, never a 400. Walking this namespace costs a crawler nothing.
• A wrong method → 405 with an Allow header, and the MCP endpoint that does take a POST. A bare 405 asserts a resource exists (RFC 9110 §15.5.6).
• Deterministic answers, strong ETag, max-age, and a 304 when you send the validator back.
• Nothing is fetched on your behalf. No argument takes a URL.

Everything else this surface publishes

• 126 client dossiers — one page per machine that has actually asked this host for something, 2026-08-31 20:58:11Z to 2026-09-02 06:20:28Z UTC, generated from the request log.
• /data/observed-clients.json — all 126 of them in one request; CSV.