Agent Card

A JSON document an A2A agent publishes at /.well-known/agent-card.json that advertises its identity, skills, endpoints and authentication.

term
Agent Card
category
identity
short_def
A JSON document an A2A agent publishes at /.well-known/agent-card.json that advertises its identity, skills, endpoints and authentication.
long_def
The Agent Card is A2A's discovery primitive — a machine-readable 'business card' hosted at a well-known URI (per RFC 8615) listing the agent's name, description, version, service endpoints, supported interfaces, capabilities (e.g. streaming) and the AgentSkill objects it offers. A client reads the card to decide whether and how to delegate a task to the agent.
see_also
a2a agent-identity agntcy
etymology_origin
Defined by the Agent2Agent (A2A) protocol; served at the well-known URI /.well-known/agent-card.json following RFC 8615 'Well-Known Uniform Resource Identifiers'.
related_to
a2a agent-identity agntcy web-bot-auth
contrast_with
Unlike llms.txt or AGENTS.md, which describe a site or repository for ingestion, an Agent Card describes a callable AGENT — its skills, endpoints and auth — so other agents can discover and delegate work to it.
example
An A2A agent publishes its Agent Card at /.well-known/agent-card.json, listing skills and endpoints so client agents can discover and delegate to it.
source
https://a2a-protocol.org/dev/topics/agent-discovery/
status
active
why_it_matters
The Agent Card is how a service makes itself discoverable and delegable in a multi-agent system; publishing one is the A2A counterpart of having a sitemap for agents.
sameAs
bridge_entity
protocols/interop/a2a
last_verified
2026-06-15
md_twin
/glossary/agent-card.md

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