Skip to content
MCP Stateless Check

MCP001 — server/discover is not implemented
Severity error
Fixed by Upgrading your MCP SDK to a release targeting 2026-07-28
Transports stdio, http
Specification 2026-07-28
Changelog entry Major change 3 (SEP-2575)

Why this changed

server/discover became mandatory in 2026-07-28. It carries the identity and version information the removed initialize handshake used to negotiate, and doubles as the backward-compatibility probe on stdio.

Running just this check

Terminal window
npx mcp-stateless --stdio "node dist/server.js" --only MCP001

Suppressing it

If this check does not apply to your server, skip it:

Terminal window
npx mcp-stateless --stdio "node dist/server.js" --skip MCP001

Rule ids are permanent and are never reissued, so a suppression cannot start silently matching a different check later.

Generated from src/rules/MCP001.ts by scripts/gen-rule-docs.mjs. Edit the rule source, not this page.