CONF-006: HTTP headers that disagree with the body are rejected with -32020

Severity	Applies to	Spec section
error	modern era, http	2026-07-28/basic/transports/streamable-http#server-validation

Sends server/discover three times: with an Mcp-Method header naming another method, with an MCP-Protocol-Version header that differs from the body, and without Mcp-Method. Each MUST be rejected with HTTP 400 and HeaderMismatch (-32020). The mismatched header names 2025-11-25, a legacy revision; a dual-era server may route such a request to its legacy handling, so for dual-era servers any HTTP 400 passes that case.

From the command line: mcpprobe checks explain CONF-006. To leave it out of a run, add "CONF-006" to [checks] disable in mcpprobe.toml; to change how much it counts, use severity_overrides.