Deep dive into the Agent2Agent (A2A) protocol, the new interoperability standard from Salesforce and Google Cloud for autonomous agent communication.
What the Agent2Agent Protocol Solves
As organizations deploy autonomous agents built on different platforms and models, those agents increasingly need to work together — one agent handing off a task, requesting data, or delegating a subtask to another. Without a shared protocol, every pairing requires custom glue code, and an agent built in one ecosystem cannot easily talk to an agent built in another. Agent2Agent (A2A), from Salesforce and Google Cloud, defines a common language and set of conventions so that independently built agents can discover each other, exchange messages, and coordinate on multi-step work.
The core idea is interoperability without central control. Rather than forcing every agent onto one runtime or one vendor's stack, A2A specifies how agents advertise what they can do and how they pass structured requests and results back and forth. An agent remains a black box internally; A2A only standardizes the boundary where two agents meet.
How Inter-Agent Communication Works
At a high level, A2A treats each participant as a service that other agents can call. One agent acts as the client initiating a request, and another acts as the responder carrying out the work and returning a result. Because agent tasks are often long-running and conversational, the protocol accommodates ongoing exchanges rather than assuming a single request-and-reply.
A few capabilities are essential for this to work in practice:
- Capability discovery — an agent can publish what tasks it handles and what inputs it expects, so other agents know when to route work to it.
- Structured task exchange — requests, intermediate updates, and final outputs travel in a consistent format both sides can parse.
- Asynchronous, multi-turn interaction — agents can send progress along the way and continue a dialogue instead of blocking on one response.
- Identity and trust boundaries — each side can establish who it is talking to before acting on a request.
Why a Shared Standard Matters
The practical payoff is composition. When agents speak a common protocol, a workflow can string together specialized agents — one that handles customer records, another that plans logistics, another that drafts communications — without any single team owning the whole chain. A shared standard also reduces lock-in: swapping one agent for a better implementation is a matter of matching the same interface, not rewriting integrations.
A2A being backed jointly by Salesforce and Google Cloud signals that the standard is meant to span vendor boundaries rather than favor one platform. That matters most when the agents you want to connect live in different clouds, different products, or different organizations entirely.
Practical Guidance for Adopters
If you are building agents today, the near-term value of A2A is designing each agent with a clear, declarable interface: what it accepts, what it returns, and what it is not responsible for. Even before you connect anything, that discipline makes agents easier to test and reuse. When you do wire agents together, keep the boundaries explicit — treat another agent's output as untrusted input, validate it, and handle the case where a downstream agent is slow, unavailable, or returns something unexpected.
Start with a narrow, well-defined handoff between two agents rather than a sprawling mesh. A single reliable delegation — one agent calling another for a specific subtask and correctly handling the result — teaches you more about the protocol's failure modes than a complex topology, and it gives you a foundation to expand as your agents mature.