Validate a single x-mcp-header value (the name portion of the resulting
Mcp-Param-{name} header) against the draft constraints, returning a
human-readable reason on violation or null when valid.
Per server/tools #x-mcp-header an x-mcp-header value:
* MUST NOT be empty;
* MUST match HTTP field-name token syntax (1*tchar, RFC 9110 §5.1);
* MUST NOT contain control characters, including CR (\r) or LF (\n).
Case-insensitive uniqueness across the whole schema is enforced separately by
validateInputSchemaHeaders (it is not a property of a value in isolation).
Validate a single x-mcp-header value (the name portion of the resulting Mcp-Param-{name} header) against the draft constraints, returning a human-readable reason on violation or null when valid.
Per server/tools #x-mcp-header an x-mcp-header value: * MUST NOT be empty; * MUST match HTTP field-name token syntax (1*tchar, RFC 9110 §5.1); * MUST NOT contain control characters, including CR (\r) or LF (\n).
Case-insensitive uniqueness across the whole schema is enforced separately by validateInputSchemaHeaders (it is not a property of a value in isolation).