# Agent Directory Service ADS

[1 · Discover](/category/discover/)

| Agent Directory Service |
| --- |
| Category | [Discover](/category/discover/) |
| Governed by | AGNTCY project (github.com/agntcy/dir); submitted as an individual IETF Internet-Draft (draft-mp-agntcy-ads) |
| Status | Internet-Draft; work in progress; canonical spec tracked at spec.dir.agntcy.org |
| Phase | draft |
| Implementation | shipping |
| Adoption | unmeasured |
| Version | draft-mp-agntcy-ads-02 (2026-07-06) |
| Specification | [https://datatracker.ietf.org/doc/html/draft-mp-agntcy-ads-02](https://datatracker.ietf.org/doc/html/draft-mp-agntcy-ads-02) |
| Found at | /.well-known/ai-catalog.json (host-local AI Finder); GET /v1/agents (REST API) |
| Acronym collisions | ADS is a generic acronym also used for Active Directory Services and Alternate Data Streams; within the agentic space, unrelated to ARDS/ARD |
| Last checked | 2026-09-06 |

[Discover](/category/discover/) The Agent Directory Service (ADS) is a distributed directory for storing and discovering metadata about AI agent applications, structured as records that can be searched by the skills they claim to provide [[1]](#ref-1). It originates from AGNTCY (an Outshift/Cisco-led project now positioned under the Linux Foundation) and is written up as an individual IETF Internet-Draft, revision -02, dated 6 July 2026, with its living canonical text tracked outside the IETF at spec.dir.agntcy.org and source at github.com/agntcy/dir [[1]](#ref-1).

## Overview
ADS solves agent discovery at scale using content-addressed storage: each agent record is packaged as an OCI-compliant artifact (reusing container-registry infrastructure and its manifest/layer model) and identified by a content ID (CID) derived from a cryptographic digest [[1]](#ref-1). Records are indexed into a distributed hash table keyed by a multi-level skill taxonomy (plus domain and module taxonomies), so a query for a capability resolves to the CIDs and peer IDs of agents that claim it, without a central registry [[1]](#ref-1). Distribution between directory nodes happens over the OCI protocol's peer-to-peer synchronization [[1]](#ref-1).

Distinct from the DHT-based global layer, ADS also runs a host-local "AI Finder" service, exposed over gRPC and, via a gateway, as a REST API: GET /v1/agents lists catalog entries with deterministic pagination, GET /v1/agents/{cid} retrieves one entry, GET /v1/agents/{cid}/export renders a stored OASF record into other ecosystems' native formats (a2a, agent-skill, mcp-ghcopilot), and GET /.well-known/ai-catalog.json serves the host's catalog document at the well-known URI this project explicitly designed to interoperate with the ARD/AI Catalog ecosystem [[1]](#ref-1). The export operation is described as ADS's "heterogeneity bridge" -- one canonical OASF record materialized into several downstream protocols' native card formats without changing its underlying storage representation [[1]](#ref-1).

ADS does not define its own agent capability schema from scratch; it uses the separately-maintained Open Agentic Schema Framework (OASF, see oasf) as its native record format, and treats other ecosystems' formats (A2A cards, MCP server descriptors) as export targets rather than first-class stored types [[1]](#ref-1).

Current state: the draft was published 6 July 2026 and expires 7 January 2027; it explicitly states it is "to be removed before publishing as an RFC," i.e. still a working draft rather than a finished document [[1]](#ref-1). Unlike several other records on this map, this one has a concrete, buildable open-source implementation (github.com/agntcy/dir) referenced directly from the spec text, which supports recording implementation as "shipping" -- but no independent count of production deployments or registered agents was located, so adoption remains unmeasured.

What is disputed or unknown: how ADS's DHT-based global layer interacts in practice with a search-first, centralized-registry model like ARD's -- the "AI Catalog Interoperability" section of the draft describes projection and export, but whether third parties beyond AGNTCY's own tooling actually consume ADS-hosted records via the ai-catalog.json path was not independently verified here.

## Discovery and probe

Content-addressed OCI-artifact storage plus a DHT for global skill-based discovery; a host-local AI Finder service exposes the same records over gRPC and a REST gateway · /.well-known/ai-catalog.json (host-local AI Finder); GET /v1/agents (REST API)

```
GET https://{origin}/v1/agents
parse:     200 response is a paginated JSON list of CatalogEntry records; a companion GET /.well-known/ai-catalog.json returns the host's WellKnownCatalog document
on absent: Host does not run an AGNTCY ADS AI Finder REST gateway; the record may still exist in the distributed hash table without a host-local HTTP surface
```

Live check run by [the MCP probe](/mcp/server-card): GET /v1/agents. An Agent Directory Service lists catalog entries as JSON at /v1/agents.

```
{
 "path": "/v1/agents",
 "expect": {
  "content_type": "json"
 },
 "note": "An Agent Directory Service lists catalog entries as JSON at /v1/agents."
}
```

## History
- 2026-09-05 — seeded from Exa Agent research run
- 2026-09-06 — verified against draft-mp-agntcy-ads-02 spec text via datatracker.ietf.org

## Instances

- [ServiceNow](https://outshift.cisco.com/blog/ai-ml/service-now-outshift-multi-agent-enterprise) · Observed 2026-09-06 · business
- [AGNTCY (Linux Foundation)](https://agntcy.org) · Observed 2026-07-29 · registry
- [agntcy/dir (AGNTCY Directory reference implementation)](https://github.com/agntcy/dir) · Observed 2026-07-06 · registry
- [Cisco Outshift / AGNTCY Directory](https://outshift.cisco.com/blog/ai-ml/agentic-resource-discover-specification-helps-agents-find-each-other) · Observed 2026-06-17 · registry
- [agntcy/dir-sdk-python](https://github.com/agntcy/dir-sdk-python) · Observed 2026-04-02 · service
- [agntcy/dir-sdk-javascript](https://github.com/agntcy/dir-sdk-javascript) · Observed 2026-04-02 · service
- [Webex (Cisco)](https://outshift.cisco.com/blog/ai-ml/webex-integrates-agntcy-directory-and-identity) · Observed 2026-03-10 · business

Every instance with its source is listed on the [instances page](/instances/).

## See also

- Not to be confused with: ADS is a generic acronym also used for Active Directory Services and Alternate Data Streams; within the agentic space, unrelated to ARDS/ARD

## References

- draft-mp-agntcy-ads-02 (6 July 2026) defines ADS as a distributed directory service storing agent metadata as content-addressed OCI artifacts, discoverable via a DHT keyed on a skill taxonomy, and exposes an AI Finder service over gRPC and REST (GET /v1/agents, GET /v1/agents/{cid}, GET /v1/agents/{cid}/export, GET /.well-known/ai-catalog.json) that is explicitly interoperable with the AI Catalog / ARD ecosystem. — [https://datatracker.ietf.org/doc/html/draft-mp-agntcy-ads-02](https://datatracker.ietf.org/doc/html/draft-mp-agntcy-ads-02) (2026-07-06) VERIFIED
- AGNTCY published a technical note describing AI Catalog interoperability layered over its directory service. — [https://blogs.agntcy.org/technical/2026/06/17/ai-catalog-over-directory.html](https://blogs.agntcy.org/technical/2026/06/17/ai-catalog-over-directory.html) (2026-06-17) REPORTED

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