An open protocol developed by Google that enables AI agents built by different vendors to communicate, collaborate, and delegate tasks to each other across organizational boundaries.
A2A is a protocol that lets AI agents from different vendors talk to each other. Without it, an agent built on one platform cannot hand off a task to an agent built on another. With it, agents can discover each other’s capabilities, negotiate task delegation, exchange messages, and manage collaborative workflows across vendor and organizational boundaries.
Google released A2A in early 2025 as an open protocol, and it has gained support from enterprise software vendors building agent ecosystems.
Why agent-to-agent communication matters
As organizations deploy multiple AI agents for different functions (marketing, sales, customer service, IT), those agents need to coordinate. A marketing agent that identifies a high-intent account needs to hand that information to a sales agent. A customer service agent resolving a complaint may need to trigger a logistics agent. Without a standard protocol, each pair of agents requires custom integration.
A2A standardizes that coordination layer so agents can collaborate regardless of who built them.
What most people get wrong
A2A solves a protocol problem, not an intelligence problem. Two agents communicating flawlessly through A2A can still produce bad outcomes if their individual logic is poorly designed. The protocol enables coordination. The quality of the coordination depends on the agents themselves, the governance around them, and the business rules they follow.
The category is also early enough that vendor claims about “A2A-compatible” agents deserve scrutiny. Supporting the protocol and using it effectively in production are different maturity stages.