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MCP registry report
Every week Lazaretto reads every remote server in the official MCP registry the way an MCP client connects, and checks what it hands an agent for tool poisoning. This page updates itself. As of 2026-10-21.
The first full pass is still running: 960 of 25,330 servers read (4%). The figures below cover the servers read so far and will settle when the pass completes.
This week
- 25,330 servers listed with a public endpoint.
- Of the 960 read: 59% listed their tools to anyone, 36% wanted credentials first, 5% could not be read.
- 6,707 tools read, 6 per server at the median.
- 65% of the servers that listed their tools also set server instructions: text a client puts in front of the model on connect, before the user asks anything.
- 1 matched a tool-poisoning rule. By rule:
pi.instruction_override1. A flagged server's page is kept out of search, and its operator is invited to tell us if the rule is wrong.
Week by week
| Week of | Listed | Read | Open | Wanted credentials | Tools | Flagged |
|---|---|---|---|---|---|---|
| 2026-10-21 | 25,330 | 960 | 59% | 36% | 6,707 | 1 |
How it is measured
Each listed endpoint is sent initialize and tools/list through an isolated
fetcher; no tool is ever called. Every tool name, description, parameter schema and server instruction is read by
deterministic rules for hidden directive blocks, orders to read local secrets, parameters built to carry secrets or the
conversation out, orders that redirect another server's tools, and invisible characters. Before these rules ran here,
they were measured against 2,784 registry servers, where an earlier version flagged one in eight, all honest; that
story is in what 2,760 MCP servers tell your agent.
A server that wants credentials is counted, not checked. Local stdio servers are not in the registry's remote list. A server can change its tools at any time. A clean read means these rules found nothing, not that a server is harmless.
Use it
Every server has its own page and README badge in the MCP registry index. Check any remote server now with the free MCP server check, or have Claude Code check each one it adds with the free lazaretto-guard plugin. The same numbers as JSON: /mcp-registry-report.json.
Cite as: Lazaretto, MCP registry report, 2026-10-21, https://lazaretto.dev/mcp-registry-report