It sounds like a House of Cards. Is it?

Description and use

Many MCP servers and A2A agents lack or misimplement their digital business cards, leading to unreliable discovery. The author sampled 50 servers, found only one compliant card, identified missing headers, fixed them, and verified compliance with SEP‑2127.

Problem

Many MCP servers and A2A agents lack or misimplement their digital business cards (Server Cards/Agent Cards), leading to unreliable discovery and connection.

Outcome

The author demonstrated that a small sample of MCP servers largely lacked compliant Server Cards, identified specific header failures, corrected them, and verified compliance, illustrating the importance of checking and maintaining card validity.

Workflow

• Sample MCP Registry for public servers
• Request each server’s card at the spec‑reserved URL
• Validate card against SEP‑2127 required headers
• Identify missing headers
• Fix server configuration to include required headers
• Redeploy server
• Re‑validate card to ensure compliance

Evidence

I took a sample of the official MCP Registry: about 50 servers with a public address. I asked each one for its card at the address the spec reserves for it.

Source

One had one. And it was a good one: small and tidy, listed in the site's own AI Catalog, with an AGENTS.md for agents to read.

Source

It failed two of the spec's required checks. Two headers a browser needs, to read the card and to ask politely whether it had changed, were both missing.

Source

I fixed them and redeployed the same day. Checked again: no required failures.

Source