MCP Server Cards and ai-catalog.json: How AI Agents Discover Your Business (2026)
AI agents increasingly research vendors on a buyer's behalf. The new MCP Server Card standard (SEP-2127) and the AI Catalog at /.well-known/ai-catalog.json let an agent discover a company's MCP server from the domain alone. Here is what the two files are, what goes in them, what deliberately does not, and how we set them up on knkoutbound.com, with the honest caveat that almost nobody uses them yet.
Kenneth Kather · Founder & CEO, KNK Outbound
Tools in this post
Key takeaways
- An MCP Server Card (SEP-2127, now final) is a small public JSON file that tells AI agents where a company's MCP server is, which transport and protocol versions it supports and what it is called, before any connection is made.
- Domain-level discovery runs through an AI Catalog at /.well-known/ai-catalog.json, which lists the card; the recommended card location is the server URL plus /server-card.
- The card deliberately contains no tool list, no credentials and no user data: agents list tools live after connecting, so a static file cannot be used to mislead them about capabilities.
- Adoption is still tiny, which is exactly why it is cheap to be early: if you already run an MCP server, publishing the two files takes an hour and makes your company findable for agents that start from your domain.
The short answer
An MCP Server Card is a small JSON file that describes a company's MCP server so that AI agents can find and connect to it without being told the address first. It became an official MCP extension with SEP-2127. The card lives next to the server, at the server URL plus /server-card, and an AI Catalog at /.well-known/ai-catalog.json on your domain points agents to it. If your company runs an MCP server, publish both. If it does not, the card is not your first step.
Why this matters now
Buyers increasingly hand vendor research to assistants: "find me three agencies that do X, compare prices, book a call with the best fit". Until now an agent could only use a company's MCP server if someone had configured the address by hand. The Server Card closes that gap. An agent that starts from a domain can check one well-known path, learn that a server exists, and connect. We explain the protocol itself in MCP explained simply.
The two files
| File | Where it lives | What it does |
|---|---|---|
| AI Catalog | /.well-known/ai-catalog.json | Domain-level index: lists the AI artifacts a domain offers, including Server Cards |
| MCP Server Card | server URL + /server-card | Describes one server: name, version, description, endpoint, transport, supported protocol versions |
- Where it lives
- /.well-known/ai-catalog.json
- What it does
- Domain-level index: lists the AI artifacts a domain offers, including Server Cards
- Where it lives
- server URL + /server-card
- What it does
- Describes one server: name, version, description, endpoint, transport, supported protocol versions
The card follows a published JSON schema. Required are a schema reference, a reverse-DNS style name such as com.example/server, a version and a description of up to 100 characters. Optional are a title, a website URL, icons, a repository and the remote endpoints with their transport type and supported protocol versions. The specification asks hosts to serve the card publicly with open CORS, a one-hour cache and an ETag.
What is deliberately not in it
No tools, resources or prompts. MCP servers can expose different tools per user, plan or configuration, so a static list could be wrong, and an agent must never make safety decisions based on a file anyone could edit. Agents list the tools live after connecting. No credentials, no internal URLs, no user data either. The card is public by design, so treat it like a business card, not like documentation.
Our live example
We run a public, read-only MCP server for agents that evaluate KNK Outbound on a buyer's behalf: company facts, public pricing, an honest fit check and the booking link, described on our page for AI agents. Since October 2026 it is discoverable:
- The card: https://knkoutbound.com/mcp/server-card, served as application/mcp-server-card+json with an ETag.
- The catalog: https://knkoutbound.com/.well-known/ai-catalog.json, served as application/ai-catalog+json, with one entry pointing to the card.
Setting both up took about an hour, because the server already existed. The card repeats what the server reports at runtime; if the two ever disagree, clients are told to trust the live server.
The honest caveat
Very few websites publish these files yet; one audit tool puts adoption at well under one in ten thousand sites. Not every assistant reads them today, and some guides still name older paths from earlier drafts. That is the argument for doing it now rather than against it: the cost is an hour, and you are findable the day clients start checking.
What it is not: a ranking factor or a replacement for being quotable. Agents still decide whom to recommend from what the web says about you, which is why being recommended by ChatGPT depends on clear, citable answers first. And for GTM teams that want to run their own stack through agents, our guide to CLI and MCP tools for GTM engineers covers the client side.
Where KNK fits
Agent discovery helps you be found by buyers who are already looking. Most of your market is not looking yet. That part is what we do: we work through your target market with cold email and LinkedIn, handle every reply, call interested prospects and book the meetings, from 3,300 euros a month, all-inclusive (pricing).
Frequently asked questions
What is an MCP Server Card?
An MCP Server Card is a public JSON file, defined in the MCP extension SEP-2127, that describes a remote MCP server before any connection: its name, version, description, endpoint, transport and supported protocol versions. It lets AI agents and registries discover and configure a server automatically. It does not list tools, which agents read live after connecting.
Where should I put the MCP Server Card and the ai-catalog.json file?
The recommended location for the card is the server's Streamable HTTP URL plus /server-card, for example https://example.com/mcp/server-card. For domain-level discovery, publish an AI Catalog at /.well-known/ai-catalog.json that lists the card's URL. Serve both publicly over HTTPS with open CORS and caching.
Do I need an MCP server card if my company does not have an MCP server?
No. The card only describes an existing MCP server, so without a server there is nothing to point to. For most companies the first steps toward being found by AI assistants are clear, citable content, consistent company facts and structured data; an MCP server and its card come later, when agents should be able to query prices or availability directly.
Will an MCP server card make ChatGPT or Claude recommend my company?
Not on its own. The card helps agents find and connect to your server once they look at your domain; whom an assistant recommends still depends on what the web says about you and how clearly your pages answer the buyer's question. Think of it as making you reachable for agents, not as a ranking factor.
Can you show me a real example of an MCP server card that is live?
Yes. KNK Outbound publishes one at https://knkoutbound.com/mcp/server-card, listed in the AI Catalog at https://knkoutbound.com/.well-known/ai-catalog.json. It points to a public, read-only MCP server that gives agents company facts, pricing, a fit check and the booking link.