A2A Protocol: How Agents Discover and Collaborate with Other Agents
~15 min read
A2A lets AI agents connect to and collaborate with OTHER agents — distinct from MCP, which connects agents to tools. Agents publish a JSON "Agent Card" describing their capabilities so others can discover and communicate with them.
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Key points
- •A2A lets agents connect with and collaborate with OTHER agents; MCP lets agents connect with tools/APIs — different, complementary roles
- •Agents collaborate by exchanging context, task updates, instructions, and data — WITHOUT sharing internal memory, thoughts, or tools
- •Remote agents publish a JSON 'Agent Card' detailing capabilities and authentication, enabling discovery
- •AI applications can model A2A agents as MCP resources, represented by their Agent Card
- •Key strength: agents built on entirely different frameworks (LlamaIndex, CrewAI, etc.) can still collaborate through this standard