Agent Card
An Agent Card is a machine-readable profile of an AI agent in the Agent2Agent protocol that describes its name, capabilities, address and supported authentication.
In the A2A protocol, every agent publishes an Agent Card as a JSON document, typically at a well-known address on its server. Other agents read it to decide whether the agent can take on a task, how to reach it and which sign-in it requires. The card lists capabilities, called skills, with descriptions and examples.
An Agent Card is a self-description. It says what an agent offers, but not whether the details are true, who operates it or what it may do on behalf of a specific customer. These questions need signed evidence.
Example
A hotel agent publishes its Agent Card: name, description, skill “search and book hotels”, interface address, sign-in through OAuth. A travel assistant reads the card, recognizes the matching skill and hands over the task. Whether the hotel agent may book is not shown by the card.
How it differs
The Agent Card describes capabilities, the agent passport proves identity and operator with a signature, and the mandate proves authority for a specific principal. Only together do they give a complete picture.
In practice
- Treat details in an Agent Card as self-disclosure, not as a verified fact.
- Publish your agent's card with current skills and the sign-in it requires.
- For actions with consequences, also require evidence of identity and authority.
Role in KYA
KYA does not verify Agent Cards. Whoever selects agents by their card should, for actions with consequences, also require verifiable evidence: an agent passport for identity and a mandate for authority.
A term from the flow, not a check of its own. To the method
Frequently asked questions
Where is an Agent Card located?
Typically at a well-known address on the agent's server, so other agents can find it without prior arrangement.
What does an Agent Card contain?
The agent's name and description, its capabilities with examples, the interface address, supported formats and the authentication it requires.
Is an Agent Card proof of identity?
No. It is a self-description. Reliable proof of identity requires a signature from an issuer the verifying party trusts, such as an agent passport.
How does the Agent Card relate to KYA?
It helps find the right agent. KYA then verifies the evidence showing whether this agent was allowed to carry out a specific action on a customer's behalf.