AgentCard

The AgentCard is a JSON document that describes an A2A agent's identity and capabilities.

Location

AgentCards must be served at:

{agent-base-url}/.well-known/agent-card.json

Agent Explorer automatically appends this path when you provide a base URL.

Required Fields

Field	Type	Description
`name`	string	Human-readable agent name
`url`	string	Agent's base URL
`version`	string	A2A protocol version (e.g., `0.3`)
`capabilities`	object	Agent capabilities
`skills`	array	List of agent skills

Example AgentCard

{
  "name": "My Agent",
  "description": "An example A2A agent",
  "url": "https://example.com/agent",
  "version": "0.3",
  "capabilities": {
    "streaming": true,
    "pushNotifications": false,
    "stateTransitionHistory": true
  },
  "defaultInputModes": ["text/plain"],
  "defaultOutputModes": ["text/plain"],
  "skills": [
    {
      "id": "general",
      "name": "General Assistant",
      "description": "Answers general questions",
      "tags": ["general"]
    }
  ],
  "supportedInterfaces": [
    {
      "url": "https://example.com/agent",
      "protocolBinding": "JSONRPC",
      "protocolVersion": "0.3"
    }
  ]
}

Capabilities

Capability	Description
`streaming`	Supports `message/stream` for SSE streaming
`pushNotifications`	Can push updates to a callback URL
`stateTransitionHistory`	Includes full state history in responses
`extendedAgentCard`	Supports the extended AgentCard format

Validation

Agent Explorer validates AgentCards and reports Errors (missing required fields, invalid types) and Warnings (missing recommended fields, potential issues).