http-protocol-version
Unsupported protocol version rejected
shipped
The sections below are generated from the CLI (methodology 0.3-draft, CLI 0.3.0); the same text is printed by sealmark explain http-protocol-version.
- pack
http- weight
- scored
- scope
- server as deployed (MCP-Protocol-Version validation)
- decided by
- http
- since
- 0.2-draft (methodology 0.3-draft)
- config keys
checks.http-protocol-version.enabledchecks.http-protocol-version.severityserver.url
Probes
old-versiontools/list with MCP-Protocol-Version: 1999-01-01, after a control tools/list with the negotiated version
Settings and thresholds
Every check also takes checks.http-protocol-version.enabled and checks.http-protocol-version.severity; they are described once in the configuration reference.
This check has no numeric threshold.
| Key | Default | Standard | Meaning |
|---|---|---|---|
server.url | none | not locked | URL of a Streamable HTTP server. Alone it must already be running; with command, Sealmark starts it and waits for this URL. |
How the verdict is established
- Scoring. scored: pass = 1 point, part = 0.5, fail = 0. A fail lowers the pack's percentage but never caps the letter.
What to fix
Answer 400 to a request whose MCP-Protocol-Version header names an unsupported version instead of quietly negotiating down.
False positives
A server that negotiates down quietly is lenient rather than unsafe; the specification says it MUST answer 400.
False negatives
Versions other than the one tried; behavior on requests that omit the header.