Listing criteria

One thing. Your service must have an interface an agent can call that completes a handshake when we probe it, on your own domain or linked from it. One of:

• MCP serveranswers an MCP initialize handshake, or asks for OAuth the way the MCP spec describes
• OpenAPI speca JSON or YAML spec that parses, describing an API an agent can call
• APIan API host (api.example.com, or a path under /api or /v1) answering in JSON — data, an auth error, or a request to be paid

These add badges on top, but none of them gets a listing in on its own:

• Skill file.md / .json / .yaml instructions agents can consume
• llms.txtLLM-readable context file
• Structured feedJSON feed, RSS, or machine-readable data

Hosting the interface somewhere else is fine — a spec on GitHub, an MCP server on a platform domain — as long as your own site links to it, from the page you list or its llms.txt. Only whoever runs your domain can publish that link, so it proves the interface is yours.

Interface badges are set by probing the URL you give us; payment protocols are documented support. They show as badges on your listing, and agents use them to filter the directory.

• No human neededthe service's own MCP server lists its tools with no credentials and it needs no key (no auth, or a wallet), or an interface answers HTTP 402 to be paid per request — an agent can start with nobody setting up a key. Documentation MCP servers don't count
• APIa live API host answering in JSON
• MCP serverpublished MCP server for zero-integration access
• OpenAPI specmachine-readable API specification
• Skill fileagent-consumable instructions or tool definitions
• llms.txtLLM-readable site context
• x402x402 — Coinbase, x402 Foundation (settlement)
• MPPMachine Payments Protocol — Stripe, Tempo (settlement)
• L402L402 — Lightning Labs (settlement)
• AP2Agent Payments Protocol — Google (authorization)
• TAPTrusted Agent Protocol — Visa (authorization)
• Agent PayMastercard Agent Pay — Mastercard (authorization)
• ACEAgentic Commerce Experiences — American Express (authorization)
• ACPAgentic Commerce Protocol — OpenAI, Stripe (commerce)
• UCPUniversal Commerce Protocol — Google, Shopify (commerce)
• ACTPAgentic Commerce Trust Protocol — Alibaba, Ant International (commerce)
• ICCIntelligent Commerce Connect — Visa (bridge)
• Webhooksasync event notifications
• Free tierfree tier or trial available
• Bot-friendly ToSterms explicitly allow automated access

• No MCP server, OpenAPI spec or API (browser-only, human-only, or llms.txt alone)
• Articles, blog posts and other content — list the product, not a post about it. URLs under /blog/, /news/, /articles/, /posts/, /insights/ or /resources/, or with a dated or article-title path, are turned away.
• More than 2 new listings from one domain in a day, or more than 3 in total
• Protocols, SDKs and frameworks on their own — a spec or a library isn’t something an agent can call. List the service that implements it; the protocols are on /protocols and the SDKs on /libraries.
• Spam or duplicate submissions

Submit your service. Your interface URLs are probed on the spot. If your MCP server, OpenAPI spec or API completes a handshake, you are live. The more agent features you support, the more badges your listing shows.