Agent skill · software engineering · aiskillstore
a2a-protocol
Builds Agent-to-Agent (A2A) servers and clients following Google's open protocol for agent interoperability. Use when the user wants to create an A2A-compliant agent, build an Agent Card, implement task management, connect agents across frameworks, set up agent discovery, handle streaming responses, implement push notifications, or orchestrate multi-agent workflows. Trigger words: a2a, agent to agent, agent2agent, a2a protocol, a2a server, a2a client, agent card, agent interoperability, agent collaboration, multi-agent, agent discovery, a2a sdk, a2a task.
Why this skill is useful
Adds executable scripts for building A2A-compliant servers and clients, enabling interoperability between agents across frameworks.
What it needs
Requires a2a-sdk, python installed locally. About 4k tokens when loaded. Last updated 2026-08-07. 405 stars on the source repository.
What this skill does
A2A Protocol Overview Implements the Agent2Agent (A2A) open protocol for communication between AI agents built on different frameworks. A2A enables agents to discover each other via Agent Cards, negotiate interaction modalities, manage collaborative tasks, and exchange data — all without exposing internal state, memory, or tools. Supports JSON-RPC 2.0 over HTTP(S), streaming via SSE, gRPC, and async push notifications. Instructions 1. Core Concepts A2A Client: Initiates requests to an A2A Server (on behalf of a user or another agent) A2A Server (Remote Agent): Exposes an A2A-compliant endpoint, processes tasks Agent Card: JSON metadata at /.well-known/agent.json describing identity, capabilities, skills, endpoint, auth Task: Unit of work with lifecycle (submitted → working → input-required → completed/failed/canceled/rejected) Message: Communication turn (role: "user" or "agent") containing Parts (text, file, or JSON) Artifact: Output generated by the agent (documents, images, structured data) 2. Python SDK Setup 3. Building an A2A Server (Python) 4. Building an A2A Client (Python) 5. Node.js SDK 6. Multi-Agent Orchestration 7. A2A vs MCP A2A MCP --- --- --- Purpose Agent-to-agent communication Agent-to-tool communication Actors Agent ↔ Agent Agent ↔ Tool/Data source Tasks Stateful, long-running, async Stateless function calls Use when Delegating to another autonomous agent Calling a specific tool/API Examples Example 1: Customer Support Router Input: "Build an A2A server that acts as a customer support router. It receives customer queries and delegates to specialized agents: billing-agent, technical-agent, and sales-agent based on the query content." Output: A2A server with Agent Card listing routing as its primary skill, message handler that classifies queries, A2A client connections to 3 downstream agents, task forwarding with context preservation, aggregated response, and fallback to human handoff. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills aiskillstore/a2a-protocol