A2A Registry

The A2A Registry is the central catalogue for discovering Agent-to-Agent (A2A) services in the Inference Gateway ecosystem. It's a static web application - hosted at registry.inference-gateway.com - that lets you browse containerised A2A agents, inspect their metadata, and pull the OCI images you need into your own gateway deployment.

The registry is open-source. The catalogue, schema, and site code all live at github.com/inference-gateway/registry.

What's in the registry

Each entry is a self-contained A2A agent published as an OCI container image. Entries carry rich metadata describing:

Identity: stable id, human-readable name, semantic version.
Purpose: a short description plus a longer markdown longDescription with features and usage notes.
Container: image repository, tag, and size so you know what you're pulling.
Provenance: author, license, homepage, repository, and documentation URLs.
Discoverability: categories and tags for filtering.

The current site lets you search across name, description, and tags, and filter by category to narrow down agents by use case (productivity, browsing, documentation, scheduling, etc.).

How it relates to ADK-built agents

If you scaffold an agent with the ADL CLI, the registry is where you publish it once it's ready for others to consume. The ADL toolchain already produces everything the registry needs:

A container image (built via the generated Dockerfile and Taskfile.yml).
An A2A-compliant agent card at /.well-known/agent-card.json.
A README.md and SCM metadata you can point homepage / documentation at.

Browsing the registry is also a good way to find reference implementations before writing your own - every published agent links back to its source repository, which typically includes its agent.yaml ADL manifest.

Discovering and consuming agents

1. Browse the registry

Open registry.inference-gateway.com and filter by category or search by keyword. Each agent card lists the OCI image (e.g. ghcr.io/inference-gateway/google-calendar-agent:0.4.23) and links to the source repo and docs.

2. Add the agent to your gateway

Use the Inference Gateway CLI's infer agents commands to register the agent with your gateway. The CLI can pull and run the image locally, or just point at an already-running URL:

Terminal

# Register a remote agent already running somewhere
infer agents add my-agent https://my-agent.example.com

# Pull and run the OCI image locally, then register it
infer agents add my-agent http://localhost:8080 \
  --oci ghcr.io/inference-gateway/google-calendar-agent:0.4.23 \
  --run

# Pass environment variables required by the agent
infer agents add my-agent http://localhost:8080 \
  --oci ghcr.io/inference-gateway/google-calendar-agent:0.4.23 \
  --run \
  --environment GOOGLE_API_KEY=...

See the A2A Integration guide for the full CLI workflow.

3. Verify and use the agent

Once registered, confirm capabilities with the gateway and start chatting:

Terminal

infer agents show my-agent
infer chat
> "What can the calendar agent do?"

For raw protocol-level inspection (agent card, task streams, conversation replay), use the A2A Debugger:

Terminal

a2a connect --server-url http://localhost:8080
a2a agent-card

Publishing your own agent

The registry is a static, build-time site: agent metadata is defined in YAML files under agents/, processed by a Vite plugin at build time, and rendered into the catalogue. There is no API to push to - publication is a pull request against the registry repo.

1. Build and publish your container image

Push your A2A agent's OCI image to a registry such as ghcr.io/<org>/<agent>:<version>. If you scaffolded with the ADL CLI and enabled spec.scm.cd: true, the generated cd.yml workflow already handles versioning, tagging, and publishing on every release.

2. Add a `metadata.yaml`

Create agents/<your-agent-id>/metadata.yaml in the registry repo using the schema below:

YAML

id: unique-agent-id
name: Human-readable Agent Name
version: 1.0.0
description: Brief description of the agent's purpose
longDescription: |
  Detailed description with features and capabilities,
  written as markdown. Use this to highlight what the
  agent does, what tools/skills it exposes, and any
  setup requirements.

image:
  repository: ghcr.io/inference-gateway/agent-name
  tag: 1.0.0
  size: 25.3MB

author:
  name: Author Name
  email: [email protected]
  url: https://github.com/your-org

license: Apache-2.0
homepage: https://github.com/org/agent
repository: https://github.com/org/agent
documentation: https://docs.example.com

categories:
  - category1
  - category2

tags:
  - tag1
  - tag2

Field	Required	Notes
`id`	Yes	Stable unique identifier (also used for the directory name)
`name`	Yes	Human-readable display name
`version`	Yes	Semantic version, must match the published image tag
`description`	Yes	One-line summary surfaced in search results
`longDescription`	Yes	Markdown body shown on the agent's detail page
`image`	Yes	`repository`, `tag`, and `size` of the OCI image
`author`	Yes	`name`, `email`, and optional `url`
`license`	Yes	SPDX identifier (e.g. `Apache-2.0`, `MIT`)
`homepage`	Yes	Project homepage URL
`repository`	Yes	Source code repository URL
`documentation`	Yes	URL to documentation (can be a README, docs site, or this docs site)
`categories`	Yes	Categorisation tags used by the registry's category filter
`tags`	Yes	Free-form tags surfaced in search

The agents/google-calendar/metadata.yaml entry is a complete working example.

3. Open a pull request

Submit the new agents/<id>/metadata.yaml against the registry repo. Once merged, the static site is rebuilt and your agent appears in the catalogue automatically.

A2A Integration - protocol overview and CLI integration
ADL CLI - scaffold A2A agents you can publish to the registry
A2A Debugger - inspect any A2A agent at the protocol level
Inference Gateway CLI - register and chat with agents through your gateway
Registry repository - source, issues, and the catalogue itself
Browse the registry - the live catalogue