ARD: publish once, be found by registries

Agentic Resource Discovery (ARD) is a draft open standard (v0.9, 2026) for the step before invocation: a domain lists its agentic resources in /.well-known/ard.json, and registries answer POST /search over everything they have crawled. Wellknown plays both roles.

Wellknown as a publisher

Our manifest is at /.well-known/ard.json (also served as /.well-known/ai-catalog.json), advertised by an Agentmap: line in /robots.txt and a <link rel="ard"> in every page. It lists three entries: this registry (application/ai-registry+json), the MCP server (application/mcp-server-card+json, card at /mcp/server.json) and the A2A agent (application/a2a-agent-card+json).

Wellknown as a registry

curl -X POST https://wellknown.network/ard/search -H 'content-type: application/json' -d '{
  "query": { "text": "find a live MCP server for Postgres",
             "filter": { "type": ["application/mcp-server-card+json"],
                         "metadata.wellknown.observedStatus": ["live"] } },
  "federation": "referrals", "pageSize": 5
}'

Results are ARD entries whose url is the record's record.json (the artifact we can vouch for; the declared card or endpoint sits inside it with provenance) and whose metadata.wellknown carries observed status, endpoint, verification and ranking signals. score is 0–100 within the page. referrals lists other registries when we know any. POST /ard/explore returns facets and GET /ard/agents pages through the index newest-first.

Getting your own catalog indexed

Publish /.well-known/ard.json with an entries array. Each entry needs identifier (urn:air:YOUR-DOMAIN:server:NAME), displayName, type and a url. For an MCP entry, point url at a server.json-shaped card with remotes or at the endpoint itself; for an A2A entry, at your Agent Card. Wellknown checks every host it already knows for a catalog at most once per fortnight and probes the endpoints it finds. To be crawled sooner, announce the host through a submission; the catalog is read on the next cycle.

The spec is a draft and may change; Wellknown tracks the published version and keeps the predecessor file name working.