a2aproject/a2a-go

a2a-go is a Go SDK for building agentic applications that implement the Agent2Agent (A2A) Protocol.

The project addresses the need for standardized communication between AI agents by providing libraries for both serving agentic functionality and consuming it. The SDK offers transport-agnostic request handlers that can be wrapped into specific transport implementations, with built-in support for gRPC, REST, and JSON-RPC. Developers define how their agent responds to requests, then register that handler with a server. On the client side, agents resolve an AgentCard to discover how another agent is exposed, create a transport-agnostic client from that information, and send requests through the resulting connection.

The tool suits teams building multi-agent systems that need to communicate over standardized protocols. It is appropriate for applications where agents must interoperate across different transport layers without tight coupling to a specific one. The SDK's extensibility allows teams to plug in custom transport implementations, authentication middlewares, and database backends rather than being locked into predefined options. A companion CLI tool exists in a separate repository for inspecting agents, sending messages, and setting up simple servers without writing code.

The project maintains clear separation between protocol specification versions and SDK versions, with the supported protocol version exported in the codebase. Documentation is comprehensive, with full API references available through the Go package documentation site and a helloworld example provided for quick starts. The maintainers request that contributors open issues before starting work on significant changes to align proposed approaches with project goals and prevent duplicated effort.