A2A lets AI agents talk to other AI agents. MCP lets AI connect to tools and data, like your calendar or product catalog. They solve different problems, work well together, and most business agents will use both.
What is A2A?
A2A, the Agent2Agent protocol, is an open standard for AI agents to find each other, understand what each can do, and work together on a task.
Google started it, and in June 2025 donated it to the Linux Foundation so no single company controls it (Google Open Source Blog). Version 1.0, its first stable release, arrived in March 2026 (A2A v1.0). A key idea in A2A is the agent card, a public file at /.well-known/agent-card.json that tells other agents who your agent is and what it can do (A2A specification).
What is MCP?
MCP, the Model Context Protocol, is an open standard for connecting AI applications to outside tools and data.
Anthropic introduced it in November 2024. The official site compares it to a USB-C port for AI: one standard plug instead of a custom cable for every device (modelcontextprotocol.io). In December 2025, Anthropic donated MCP to the Agentic AI Foundation under the Linux Foundation (Anthropic).
What's the difference, in one picture?
Imagine your business agent is a new front-desk employee.
- MCP is how that employee reaches the back office: the booking calendar, the price list, the inventory system.
- A2A is how that employee talks to visitors at the front door, in this case other people's AI assistants.
| A2A | MCP | |
|---|---|---|
| Connects | Agent to agent | AI to tools and data |
| Business example | A customer's assistant asks your agent about Saturday openings | Your agent checks your calendar for Saturday openings |
| Started by | Anthropic | |
| Now governed by | Linux Foundation | Agentic AI Foundation (Linux Foundation) |
Do I need to choose one?
No. They're complementary, and the A2A specification itself includes a section on how it relates to MCP.
In a typical setup, a customer's assistant reaches your agent over A2A, and your agent uses MCP to look up the real answer in your systems. You don't need to manage either one; you need an agent built to support both, which is what our Business Agent Build does.
What should I take away?
- Both standards are open and governed by neutral foundations, which makes them safer to build on.
- Neither replaces the basics. Assistants still need clear facts about your business.
- Start with what pays off today, and choose a partner that builds on open standards.