a2a

name	a2a
description	Agent2Agent (A2A) interoperability for Hermes. Slice 1 exposes Hermes' existing tools and skills as an A2A Agent Card served at /.well-known/agent.json, so other A2A-speaking agents can discover what this Hermes instance can do. Discovery only -- no A2A JSON-RPC server yet.
version	0.1.0
metadata	{"hermes":{"tags":["a2a","interoperability","agent-card","discovery"],"category":"interoperability","related_skills":["autonomous-ai-agents"]}}

A2A Agent Card (discovery)

Hermes advertises itself to the Agent2Agent (A2A) ecosystem with an Agent Card: a small JSON document that describes the agent's identity, endpoint, auth methods, protocol capabilities, and the list of things it can do (its "skills").

This slice (issue #879, child of #748) implements discovery only:

• The Agent Card data model lives in hermes_cli/a2a.py (AgentCard, AgentSkill, build_agent_card).
• The dashboard web server (hermes_cli/web_server.py) serves the card at GET /.well-known/agent.json.
• Each existing Hermes tool and each SKILL.md skill is mapped to one entry in the card's skills[] array. No new core tools are registered -- the card is a read-only view over capabilities Hermes already has.

Configuration

All behaviour is driven by config.yaml in this directory, which overlays the defaults baked into hermes_cli/a2a.py. Highlights:

• enabled: false makes the endpoint return 404 (Hermes stops advertising).
• name / description / provider set the card's identity.
• url is the A2A service endpoint; a relative value (/a2a) is resolved against the incoming request host so no hostname is hardcoded.
• authentication.schemes lists the advertised auth methods.
• expose.tools / expose.skills / expose.max_skills control which capabilities are surfaced and the cap on the total.

Scope note

The card is a public discovery document by design (A2A clients hold no dashboard session). It contains only tool/skill names and one-line descriptions -- never secrets or config values. The A2A JSON-RPC server that actually fulfils tasks (url), plus streaming and push notifications, are later slices (#880 client, #881 server).