A remote MCP server runs as an HTTPS service; a local one runs as a subprocess over stdio. Either way it answers an initialize handshake, declares its capabilities, and lists tools — each with a name, a description and a JSON-Schema input.
The quality bar that decides whether agents actually use a server: clear tool descriptions (agents pick tools by description), valid input schemas, low handshake latency, and a deliberate auth posture.
Run a real initialize + tools/list handshake and check protocol conformance, tool-description coverage, latency and TLS. A free scan surfaces all of it in seconds.