A2A (Agent2Agent)
A2A is an open standard that lets AI agents from different companies find each other, hand each other tasks and pass back the results.
A2A, short for Agent2Agent, is an open standard that lets AI agents talk to each other. One agent can find another, ask it to do part of a job, and get the result back, even when the two were built by different companies with different tools.
Google started A2A and later gave it to the Linux Foundation, where a group of companies now looks after it. The A2A site has the full specification.
What it's for
Most agents are good at a few things. A travel agent might know flights, and a hotel company's agent might know its own rooms and prices. A2A gives them a shared way to work together, so the first agent can hand the hotel part of a trip to the second without either one having to show the other how it works inside.
For example, someone asks their assistant to plan a weekend in Bath. The assistant books the train itself, then asks a hotel group's agent for a room under £150 a night, and a restaurant's agent for a table on Saturday. Three agents, one plan, and the person never opened a website.
A2A and MCP
You'll often see A2A next to MCP. They do different jobs. MCP connects an agent to tools and data, like a database or a calendar. A2A connects an agent to another agent. An agent might use both in the same task.
Why a marketer should care
Today, people ask an assistant and read its answer. As agents start passing work to each other, more of the buying journey may happen between machines. If your business ever runs its own agent, for bookings or support, A2A is one of the ways other agents could reach it.
It's early. For most brands, the work that matters now is still the basics: pages that state your facts plainly, and bots that are allowed to read them.