What is A2A?
A2A (Agent-to-Agent) is Google's open protocol for AI agents to discover, authenticate, and communicate with each other. A site publishes an Agent Card — a JSON manifest at /.well-known/agent.json — that advertises the agent it hosts, what it can do, and how other agents can interact with it.
When does A2A apply?
A2A applies to sites that host an AI agent — a service that other agents can talk to programmatically. Examples:
- A customer support agent that processes refunds
- An AI assistant that answers domain-specific questions
- A booking agent that handles reservations
If your site only serves content to humans or exposes a REST API, A2A is not applicable. Use OpenAPI for APIs and llms.txt for content.
What AgentGrade checks
Agent Card published — We check for a JSON file at /.well-known/agent.json.
Agent Card verified — The card must contain at least name and url fields so other agents can identify and connect to your service.
How to implement
Publish a JSON file at /.well-known/agent.json:
{
"name": "My Support Agent",
"description": "Handles customer inquiries and refunds",
"url": "https://example.com/agent",
"capabilities": {
"streaming": true,
"pushNotifications": false
},
"skills": [
{
"id": "refund",
"name": "Process Refunds",
"description": "Process customer refund requests"
}
]
}