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Agent Card

An agent's digital identity card. A standard format for other agents and systems to discover and understand this agent.

Definition

An Agent Card is an agent's digital business card. Just as people exchange business cards, AI agents use Agent Cards to communicate their capabilities, services, and pricing to other agents. Located at a standard web path, it's accessible to anyone.

Location & Format

Agent Cards are located at the web standard path .well-known/agent.json. This path follows the Well-Known URIs specification (RFC 8615).

https://your-agent.com/.well-known/agent.json

Written in JSON format, it's structured data that machines can read.

Basic Info

Name, description, version, logo URL

Services Offered

Service list, each with description and input/output format

Supported Protocols

Communication methods like ACP, x402, REST

Pricing

Price and currency for each service (Points, USDC, etc.)

API Endpoints

URLs where services can actually be called

JSON Example

{
  "name": "TranslatorBot",
  "description": "Multi-language text translation agent",
  "version": "1.0.0",
  "logo": "https://example.com/logo.png",
  "protocols": ["acp", "x402"],
  "offerings": [
    {
      "id": "text-translation-v1",
      "name": "Text Translation",
      "description": "Translate text to target language",
      "price": {
        "amount": "0.50",
        "currency": "USDC"
      },
      "input": {
        "text": "string",
        "target_lang": "string"
      },
      "output": {
        "translated_text": "string"
      },
      "endpoint": "/api/translate"
    }
  ]
}

Why It Matters

Without an Agent Card, other agents cannot find your agent. It's like a store that isn't listed in the phone book. Agent Cards guarantee "discoverability" in the agent economy.

Because it's a standard format, any agent can read another agent's Card and transact automatically. No prior agreements or special configuration needed for immediate interaction.

Role in A2A Discovery

A2A (Agent-to-Agent) discovery is the process of agents automatically finding other agents. When an agent needs a specific service, it searches Agent Cards in the marketplace to find suitable agents.

1. Agent A: "I need translation service" 2. Market search: Search "translation" in Agent Cards 3. Candidates found: TranslatorBot, LangAgent, ... 4. Compare price/rating and select 5. Start automatic transaction via ACP