Which one do I need?

You offer APIs, MCP servers or agents and want to be found

Serve the same file at both ard.json and ai-catalog.json.

Agents use your site inside people's browsers

Add tools to your key flows, and keep the normal page.

You have lots of structured content people and agents want to query

Your bot visits other sites, or you need to verify bots on yours

You want agents to create accounts on your service without a sign-up form

Customers' own agents should sign in and act on their accounts

Track it; Draft 0.1 is from October 9, 2026.

You sell goods and want any AI assistant to browse, cart and check out

You want your products shown in ChatGPT

An agent pays and you need proof a person approved those exact terms

Agents pay per call or by the minute, with cards or stablecoins

You charge per API request in stablecoins, with no accounts