Agent2Agent (A2A) Protocol Documentation
by Linux Foundation
Learn the open standard that lets agents from different frameworks discover each other and delegate work.
Overview
A2A is an open protocol, originally built by Google and now governed by the Linux Foundation under a Technical Steering Committee that includes AWS, Cisco, Google, IBM Research, Microsoft, Salesforce, SAP and ServiceNow, that standardizes how autonomous agents discover one another and delegate tasks. The documentation site covers the full protocol specification (now at version 1.0), core concepts, Python and JavaScript tutorials, SDK references, and enterprise features such as authentication and signed Agent Cards. The central primitives are the Agent Card (machine-readable metadata advertising an agent's capabilities and endpoint), the Task (the unit of work one agent delegates to another, with a defined lifecycle and streaming status updates), and the transport layer built on HTTP, JSON-RPC 2.0 and Server-Sent Events. The docs are explicit that A2A is a communication protocol, not an agent framework, and that it complements rather than replaces the Model Context Protocol: MCP standardizes agent-to-tool calls, while A2A standardizes agent-to-agent collaboration. Released under the Apache 2.0 license with SDKs in Python, JavaScript, Java, Go and .NET.
At a Glance
- Topic
- Agentic
- Level
- Intermediate
- Format
- Documentation
- Cost
- Free
- Duration
- ~3-5 hours to work through the spec + tutorials
- Provider
- Linux Foundation
- Hands-on
- Yes — code/exercises
- Certificate
- None
What You’ll Learn
- ✓How to publish an Agent Card so other agents can discover your agent's skills and endpoint
- ✓The A2A task lifecycle — submitting, streaming status updates, and returning artifacts across agent boundaries
- ✓How A2A maps onto HTTP, JSON-RPC 2.0 and Server-Sent Events, including long-running and push-notification flows
- ✓Where A2A ends and MCP begins, so you pick the right protocol for agent-to-agent vs. agent-to-tool problems
- ✓How to implement an A2A client and server with the official Python or JavaScript SDK
- ✓Enterprise concerns: authentication, authorization, and signed Agent Cards for cross-organization trust
Highlights
- •Vendor-neutral: governed by the Linux Foundation with a TSC spanning AWS, Google, Microsoft, IBM, Salesforce, SAP and ServiceNow
- •Version 1.0 of the spec is stable, with production SDKs across five languages
- •Step-by-step tutorials in Python and JavaScript, not just a dry specification
- •Explicitly positioned alongside MCP so the two protocols compose rather than compete
Who It’s For
Best For
- ✓AI engineers building multi-agent systems that span frameworks or teams
- ✓Platform teams standardizing how internal agents expose and consume capabilities
- ✓Architects evaluating agent interoperability standards for enterprise deployment
Prerequisites
- •Comfort with HTTP APIs and JSON-RPC-style request/response
- •Working knowledge of Python or JavaScript
- •Basic familiarity with LLM agents and tool calling
FAQ
What is Agent2Agent (A2A) Protocol Documentation?
The official documentation for the Agent2Agent (A2A) Protocol, the Linux Foundation-governed open standard for agent-to-agent communication. It is aimed at AI engineers building multi-agent systems who need agents written in different frameworks or owned by different teams to interoperate without exposing their internal logic.
Is Agent2Agent (A2A) Protocol Documentation free?
Agent2Agent (A2A) Protocol Documentation is free to access.
What level is Agent2Agent (A2A) Protocol Documentation for?
Agent2Agent (A2A) Protocol Documentation is aimed at a intermediate audience. Recommended background: Comfort with HTTP APIs and JSON-RPC-style request/response, Working knowledge of Python or JavaScript, Basic familiarity with LLM agents and tool calling.
How long does Agent2Agent (A2A) Protocol Documentation take?
Expect roughly ~3-5 hours to work through the spec + tutorials. Most learners work through it at their own pace.
What will I learn from Agent2Agent (A2A) Protocol Documentation?
You'll learn: How to publish an Agent Card so other agents can discover your agent's skills and endpoint; The A2A task lifecycle — submitting, streaming status updates, and returning artifacts across agent boundaries; How A2A maps onto HTTP, JSON-RPC 2.0 and Server-Sent Events, including long-running and push-notification flows; Where A2A ends and MCP begins, so you pick the right protocol for agent-to-agent vs. agent-to-tool problems; How to implement an A2A client and server with the official Python or JavaScript SDK; Enterprise concerns: authentication, authorization, and signed Agent Cards for cross-organization trust.