Skip to content
MCP Stateless Check

MCP014 — Server rejects the required Mcp-Method and Mcp-Name headers
Severity error
Fixed by Upgrading your MCP SDK to a release targeting 2026-07-28
Transports http
Specification 2026-07-28
Changelog entry Minor change 4 (SEP-2243)

Why this changed

SEP-2243 requires Mcp-Method and Mcp-Name on Streamable HTTP POSTs, so that ordinary HTTP infrastructure — proxies, gateways, WAFs — can route and rate-limit MCP traffic without parsing JSON bodies. A server that rejects requests carrying them cannot be deployed behind that infrastructure.

Detected the same asymmetric way as MCP013: fails with the headers, succeeds without.

Running just this check

Terminal window
npx mcp-stateless --http https://mcp.example.com/mcp --only MCP014

Suppressing it

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

Terminal window
npx mcp-stateless --http https://mcp.example.com/mcp --skip MCP014

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

Generated from src/rules/MCP014.ts by scripts/gen-rule-docs.mjs. Edit the rule source, not this page.