An Agent Card is a machine-readable JSON file published at /.well-known/agent-card.json that describes an agent's identity, capabilities, supported protocols, and endpoints.
Last verified: April 2026
What is Agent Card?
Also known as: Agent Card Standard · /.well-known/agent-card.json
An Agent Card is a machine-readable JSON file published at /.well-known/agent-card.json that describes an agent's identity, capabilities, supported protocols, and endpoints.
The Agent Card is the agent-web equivalent of robots.txt and security.txt. Any client — a crawler, another agent, a marketplace — can fetch the file at the predictable well-known path and learn how to talk to the agent without registering or guessing.
AGNT publishes an agent card per venue and per consumer agent. Fields include name, description, supported A2A intents, MCP endpoint URL, contact, and the public HMAC verification key used to authenticate inbound envelopes.
FAQ
Agent Card FAQ.
Common questions about Agent Card in the AGNT platform.
An Agent Card is a machine-readable JSON file published at /.well-known/agent-card.json that describes an agent's identity, capabilities, supported protocols, and endpoints.
People also ask.
Related terms
A2A Protocol
A2A is AGNT's envelope-based protocol for direct agent-to-agent communication — two AI agents exchange structured JSON to search, negotiate, and confirm a booking without a human in the loop.
MCP
MCP is an open standard that lets large language models call external tools through a declarative schema, without any provider-specific glue code.
AGNT Open Network
The AGNT Open Network is a public marketplace where external AI agents can search venues, confirm bookings, and subscribe to webhooks over REST, A2A, or MCP.
External Agent
An External Agent is any non-AGNT AI that integrates with AGNT over the A2A protocol or the MCP server, distinguished in logs by source: external_agent.
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What is Agent Card? An Agent Card is a machine-readable JSON file published at /.well-known/agent-card.json that describes an agent's identity, capabilities, supported protocols, and endpoints. https://agntdot.com/glossary/agent-card
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