Learn AI · Level 4 · Frontier view · step 2 of 17 · word 1 of 1
What is the agent-to-agent (A2A) protocol?
A2A is an open standard that lets AI agents built by different companies find each other, share tasks and send back results. MCP connects an agent to tools; A2A connects agents to each other.
In plain English
Google started A2A, and in June 2025 it became a Linux Foundation project, with support from companies including AWS, Cisco, Microsoft, Salesforce, SAP and ServiceNow. As the A2A project explains it, MCP gives one agent more tools, while A2A lets separate agents work together.
An example
Your company’s travel agent needs a hotel. Instead of using a website, it asks a hotel chain’s booking agent, which checks rooms and replies with options. Neither company has to see how the other’s agent works inside.
What to watch out for
Every agent you let in is a new risk. Agents need to check who they are talking to, share only what the task needs (least privilege), and keep a person approving payments and other actions that can’t be undone.
Learn AI path · Level 4 · Frontier view · step 2 of 17
Done? Next stepFaster, cheaper, smarter →See all of level 4