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Moving from ai-catalog.json to ard.json

If you published before September 2026, you are probably on the old path. Moving takes about ten minutes and nothing in your entries has to change.

ai-catalog.json is the predecessor. ARD v0.91, on 26 August 2026, made /.well-known/ard.json the normative path and rel="ard" the link relation. Consumers must fetch the new path; consulting the old one is optional, so a resource that stays there may simply not be found.

Your entries do not change. Copy the file to the new path, emit the new link relation, and leave the old file up until registries have re-crawled you.

What changed, and when

ARD v0.91, dated 26 August 2026, moved the manifest. The old names came from the predecessor format that ARD was built on.

	Predecessor	Current
Manifest path	`/.well-known/ai-catalog.json`	`/.well-known/ard.json`
Link relation	`rel="ai-catalog"`	`rel="ard"`
Consumer obligation	May be consulted, optional	MUST be fetched, MUST be honoured

Publishers publish entries at /.well-known/ard.json and emit rel="ard". There is no need to serve the predecessor path or relation as well. A resource that remains only at /.well-known/ai-catalog.json may not be found, since consulting that path is optional for consumers, a publisher on the predecessor path SHOULD move to ard.json.
ARD specification v0.91, section 5.1, Consumer resolution agenticresourcediscovery.org

Why so much documentation still says the old name. Nearly every article you will find about ARD was written in the week of the June 2026 announcement and says ai-catalog.json, including Google's own announcement post. Those posts are dated news and will not be corrected. The specification is the authority, and it changed in August.

The migration, in three steps

1. Copy the file

The content does not change. Same JSON, new path.

that is genuinely it

cp .well-known/ai-catalog.json .well-known/ard.json

2. Update the link relation, if you emit one

in your page head

<!-- before -->
<link rel="ai-catalog" href="/.well-known/ai-catalog.json">

<!-- after: keep both while registries re-crawl -->
<link rel="ard" href="/.well-known/ard.json">
<link rel="ai-catalog" href="/.well-known/ai-catalog.json">

3. Leave the old file up for a while

Serving both costs nothing and protects you from registries that have you on a slow crawl schedule. Once you can see your entries appearing from the new path, drop the old one. Do not redirect the old path to the new one: some crawlers do not follow redirects on well-known paths, and a redirect is a worse outcome than a plain copy.

Check it worked

Fetch it yourself first, then let the validator confirm the rest.

the two things to verify

curl -sI https://yourdomain.com/.well-known/ard.json | head -3
# expect: HTTP/2 200
#         content-type: application/json

Get indexed

Moving the file does not re-crawl you. A registry will find the new path on its own schedule, which nobody promises, or immediately if you say so.

one call, any ARD registry that accepts submissions

curl -X POST https://neuronto.com/submit \
  -H "Content-Type: application/json" \
  -d '{"url": "https://yourdomain.com"}'

Disclosure: Neuronto is run by the people who write this site, and it is named first for that reason as much as any other. It resolves a bare domain to your manifest, indexes entries of every type rather than MCP servers only, and answers with what it found or exactly what it tried. Add "dry_run": true to see the outcome without being written anywhere.

The other public registries take submissions through their own doors, and submitting to several costs nothing: WellKnown, ARD Registry Hub, Desvela. What actually reaches all of them over time is the manifest on your own domain, which is the part nobody can take away from you. How each one behaves, probed.

Check the new path Field reference

Questions

Do I have to migrate?

You should. Consulting ai-catalog.json is optional for consumers, so a conformant registry may never look at it. The specification's own wording is that a publisher on the predecessor path should move.

Will I lose my existing indexing?

Not if you leave the old file in place while registries re-crawl. Nothing forbids serving both, and serving both is the safe way to move.

Does the entry format change too?

No. Entries written for the predecessor remain valid unchanged. v0.91 restated them as JSON-LD nodes, and was explicit that this is a repositioning rather than a redefinition. You are renaming a file and a link relation, not rewriting content.

Last reviewed 2026-09-04. Checked against ARD v0.91 (Proposal, 2026-08-26).