Reference
ARD specification changelog
The specification is a proposal and it moves. Most published coverage predates the August revision and is wrong about the manifest path.
The change that matters: v0.91, on 26 August 2026, renamed the manifest from /.well-known/ai-catalog.json to /.well-known/ard.json and replaced rel="ai-catalog" with rel="ard". The same revision restated entries as JSON-LD nodes, which adds a @context seam without invalidating anything already published.
Why this page exists
The specification is a proposal and it moves. The August revision renamed the manifest, which means most of the coverage published in June is now wrong on the single most important detail. Nobody is going back to correct those posts. This page tracks what changed so you can tell whether something you read still applies.
How this is compiled. Compiled by reading successive revisions of the published specification. It is not an official changelog and the working group does not maintain one at the time of writing. If something here is wrong, it is ours to fix.
v0.91 · 26 August 2026 · status Proposal
The manifest was renamed
| Before | After | |
|---|---|---|
| Manifest path | /.well-known/ai-catalog.json | /.well-known/ard.json |
| Link relation | rel="ai-catalog" | rel="ard" |
| Consumer duty | n/a | MUST fetch ard.json, MUST honour rel="ard". Consulting the predecessor is optional. |
The practical consequence is stated plainly in section 5.1: a resource that remains only at the predecessor path may not be found, because consulting it is optional for consumers. A publisher on the old path should move. Ten-minute migration.
Entries became JSON-LD nodes
An entry is now a JSON-LD node whose plain terms resolve through a base context published at
https://agenticresourcediscovery.org/context/v1, mapping to the default namespace
https://agenticresourcediscovery.org/ns#. An entry may declare its own
@context to draw terms from additional vocabularies, and those terms become available
as filter dimensions with no further spec change.
Nothing published before this breaks. The specification says so directly, calling it a
repositioning rather than a redefinition, and carrying @context in an entry is
optional. You want it when the entry will be read by generic JSON-LD tooling that has not been told
it is looking at ARD, which in practice means in-page markup.
Queries gained a context too
The query object in 5.3.1 now takes @context alongside text and
filter, so a filter key naming a namespaced term resolves to an IRI rather than being
matched as a literal string. That is what lets a client filter on okf:taxonomy and
match an entry whose author bound the same namespace under a different prefix.
The catalog entry and the ARD entry were separated
Section 4 now states explicitly that the two are different objects and that their conformance is self-contained: a change to what a catalog entry requires does not change what an ARD entry requires. This is the formal version of the distinction that explains why a valid manifest can be unfindable.
Original release · 17 June 2026
Announced by Google, with launch coverage from Microsoft, AWS, Hugging Face and Cisco the same
week. The manifest was ai-catalog.json. Built on the AI Catalog data model from the
Linux Foundation's AI Catalog Working Group, licensed Apache 2.0.
What to watch
- Media type registration.
application/mcp-server-card+jsonandapplication/a2a-agent-card+jsonare not formally registered with IANA, and the specification warns the format may change. This is the most likely next break. - A concrete signing scheme. The document says a future ARD profile may pin one and that this revision deliberately does not. Until then, two registries verifying the same manifest agree only because they both defer to the declared framework.
- Retrieving a full entry by identifier. Explicitly out of scope for this draft. A client that needs the complete entry has to go back to the publisher.
- Version 1.0. Status is still Proposal. Nothing here is settled until that changes.
Last reviewed 2026-09-04. Checked against ARD v0.91 (Proposal, 2026-08-26).