Probing all 30,516 MCP registry servers: 1 in 9 is broken, and the failures repeat
xakpc · reddit · 2026-10-21
A developer probed every remote endpoint in the official MCP registry — 30,516 servers — with a basic handshake + tools/list flow. Results: 51% work, 31% are alive but require auth, and roughly 1 in 9 is simply broken. The failures follow predictable patterns:
- Auth: servers should return 401 + WWW-Authenticate (not 404/500); only 22% of auth-protected servers declare required headers in their registry entry
- Hosting: 948 endpoints 404 (routes moved without registry updates), 577 return 5xx, 539 dead DNS, 249 TLS failures; broken rates by host — Railway 50%, Render 39%, Cloudflare Workers 6%
- Protocol: 222 servers advertising the new protocol fail server/discover (often missing supportedVersions); 126 answer MCP POSTs with empty 200 OKs
- Tool quality: 41% of working servers never set readOnlyHint/destructiveHint; 27% of arguments lack descriptions; only 29% have outputSchema; median tool list is 2k tokens, with 741 servers burning 25k+; 520 publishers ship a tool just named "search"
- Hygiene: listings untouched since April are 40% broken; handshake + tools/list still can't prove the backing service works
The inspector is available at mcpcanary.com, with the full report published alongside.
Related event: MCP Registry Scan: Half of Servers Open to Strangers, 1 in 9 Broken(2 posts)→
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