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Agent-to-Agent Protocol (A2A)

A2A is an open protocol enabling AI agents to communicate and collaborate across platforms. Learn how to build and connect A2A-compatible agents.

What is A2A?

A2A (Agent-to-Agent Protocol) is an open protocol that enables AI agents to discover and communicate with each other across different platforms and vendors. Originally launched by Google and now maintained by the Linux Foundation, A2A provides a standardized way for agents to collaborate on complex tasks.

Current Implementation

FeatureStatus
StreamingA2A waits for the complete response before returning results
AuthenticationNone or API key based
DiscoveryVia agent-card.json

Core Concepts

AgentCards

Every A2A agent exposes an AgentCard — a JSON file at /.well-known/agent-card.json that describes the agent's capabilities. This enables automatic discovery.

json
{
  "name": "Research Agent",
  "description": "Searches and summarizes academic papers",
  "url": "https://research-agent.example.com",
  "version": "1.0.0",
  "skills": [
    {
      "id": "paper-search",
      "name": "Paper Search",
      "description": "Search academic databases for relevant papers"
    },
    {
      "id": "summarize",
      "name": "Summarize Paper",
      "description": "Generate a concise summary of a research paper"
    }
  ]
}

Communication Flow

  1. Discovery — Client fetches /.well-known/agent-card.json to learn agent capabilities
  2. Task Creation — Client sends a task request with input data
  3. Processing — Agent processes the task and generates a complete response
  4. Response — Agent returns the full result (no streaming)

When to Use A2A

Use CaseA2AMCP
Query a database✓
Call an API✓
Delegate research to a specialized agent✓
Coordinate multiple agents on a task✓
Connect to external tools/services✓
Agent-to-agent collaboration✓

Resources