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A2A Protocol

08 agent-communication/A2A Project/ACTIVE/aka Agent2Agent, A2A

A2A (Agent2Agent) is the open protocol for cross-vendor agent communication — Google-originated, now governed at the Linux Foundation — standardizing Agent Cards for capability discovery plus task-based messaging between agents.

SEC.01

What it does

  • 01Agent Cards for capability discovery
  • 02Task lifecycle and artifacts
  • 03Streaming updates
  • 04Vendor-neutral governance (Linux Foundation)
  • 05Composes with MCP
SEC.02

Who it's for

Exposing an agent to third-party callers, or wiring agents from different vendors into one workflow without bespoke adapters.

PRICING

Pricing

Open protocol (free). List prices as checked against the vendor's pricing page on 2026-09-25; plans change often, so confirm before deciding.

caveat · before you adopt

The spec is still moving — most real deployments are intra-org, and several big vendors ship partial support.

ALT

Other agent communication platforms (12)

OpenScout / Scout

OpenScout · agent-communication

cli/api · local · Free (OSS), local

AGNTCY

AGNTCY · agent-communication

api · local/cloud · Free (OSS, Apache-2.0)

Agent Network Protocol

Community / OSS · agent-communication

api · local/cloud · Open protocol (free)

NANDA

NANDA (MIT Media Lab) · agent-communication

api · local/cloud · Free (research project)

BeeAI

IBM · agent-communication

api/cli · local/cloud · Free (OSS, Apache-2.0)

CrewAI

CrewAI · agent-communication

api/cli · local/cloud · Free OSS core; CrewAI Enterprise paid (verify)

Microsoft Agent Framework

Microsoft · agent-communication

api · local/cloud · Free OSS (MIT); Azure hosting via Foundry

LangGraph

LangChain · agent-communication

api · local/cloud · Free OSS; LangGraph Platform paid tiers

MetaGPT

DeepWisdom · agent-communication

api/cli · local/cloud · Free OSS; MGX hosted product paid (verify)

CAMEL

CAMEL-AI · agent-communication

api · local/cloud · Free (OSS, Apache-2.0)

Agency Swarm

VRSEN · agent-communication

api · local/cloud · Free (OSS)

OpenAI Agents SDK

OpenAI · agent-communication

api · local/cloud · Free (OSS SDK); model usage metered
VS

Head-to-head (1)

FAQ

Frequently asked

What is A2A Protocol?

A2A (Agent2Agent) is the open protocol for cross-vendor agent communication — Google-originated, now governed at the Linux Foundation — standardizing Agent Cards for capability discovery plus task-based messaging between agents.

Who is A2A Protocol for?

Exposing an agent to third-party callers, or wiring agents from different vendors into one workflow without bespoke adapters.

How much does A2A Protocol cost?

Open protocol (free). List prices as checked against the vendor's pricing page on 2026-09-25; plans change often, so confirm before deciding.

Does A2A Protocol run locally or in the cloud?

A2A Protocol runs locally on your machine and in the vendor's cloud. Its interfaces are an API or protocol.

What are alternatives to A2A Protocol?

Other agent communication platform entries in the catalog: OpenScout / Scout, AGNTCY, Agent Network Protocol, NANDA, BeeAI, CrewAI, Microsoft Agent Framework, LangGraph, MetaGPT, CAMEL, Agency Swarm, OpenAI Agents SDK. Different categories solve the same problem differently — see the Agent communication & collaboration category page for tradeoffs.

What should I know before adopting A2A Protocol?

The spec is still moving — most real deployments are intra-org, and several big vendors ship partial support.