CONF-002: Requests missing required _meta fields are rejected with -32602

Severity	Applies to	Spec section
error	modern era, stdio, http	2026-07-28/basic/index#meta

Sends server/discover once without io.modelcontextprotocol/protocolVersion (stdio only) and once without io.modelcontextprotocol/clientCapabilities. A request missing a required field is malformed and MUST be rejected with -32602 Invalid params; on HTTP with status 400. Over HTTP the missing-version case is skipped, because the body then also disagrees with the required MCP-Protocol-Version header, for which -32020 is equally required.

From the command line: mcpprobe checks explain CONF-002. To leave it out of a run, add "CONF-002" to [checks] disable in mcpprobe.toml; to change how much it counts, use severity_overrides.