ai-catalog
AI Catalog
Your site's table of contents for AI.
Reality check
Early, with experimental catalogs at GitHub, Buildkite and Hugging Face. The fix is easy, serve the same file at both ai-catalog.json and ard.json.
How it works
Like a table of contents, it doesn't contain the chapters; it tells you where each one is. MCP servers, AI agents, plugins and datasets each invented their own way to be found, so an assistant would have to know a dozen conventions. AI Catalog replaces that with one JSON list at /.well-known/ai-catalog.json, where each entry says what kind of thing it is and either links to its full description or includes it.
A restaurant that works with a booking provider and a jobs provider can list both AI tools, so any assistant that only knows the restaurant's web address can find the booking tool. Catalogs can also point to other catalogs, so a big platform can list many sub-catalogs.
Who's behind it
It's developed in a Linux Foundation working repository (started October 2025) with members from the MCP and A2A communities, and published at ai-catalog.io. Even the group's name is inconsistent: ai-catalog.io calls it the "Agent Card Working Group," while Google thanks the "AI Catalog Working Group."
Its biggest recent boost: MCP's "Server Cards" proposal points discovery at ai-catalog.json (reported as finalized October 6, 2026, though one implementer still saw it in review). ARD calls ai-catalog its predecessor, but ai-catalog sees itself as a lightweight publishing format that stays separate: it was split off, not retired.