We probed 22,312 public MCP servers the way an AI agent does — run the handshake, list the tools, check the schema. Not just whether the URL returns 200. Here's what we found.
Of 22,312 servers with a remote endpoint, 11,196 connect and list tools without credentials. Another 6,596 are alive but gated behind an API key, and 4,520 are unreachable or non-conformant.
A plain uptime monitor pings a URL and calls a 200 “up.” But an MCP server can return 200 and still be useless to an agent: it exposes no tools, sits behind an auth wall, or its tool schema silently changed. Reliability for agents is the handshake succeeding and the tools being there — not the HTTP status. Median healthy connect time was 1,711 ms (p90 2,788 ms).
The most common reasons a server didn't return a usable tool list:
The public MCP registry lists 62,992 servers — but only 22,312 expose a remote endpoint you can actually reach from outside (the rest are local/package-only). Of those reachable, half are healthy. The ecosystem is younger and more fragile than the headline server count suggests.
initialize → tools/list, and record reachability, tool count, schema fingerprint and a verdict. Read-only — no tool is ever called. Snapshot: 2026-08-17. Live data: /data/servers.json.Browse the full reliability directory, or add the free MCP Uptime tool so your AI agent can ask which servers actually work — health, latency, tools — live in its workflow.