It's easy to lump every agent protocol into one bucket, but MCP and A2A solve genuinely different problems, and the confusion between them usually comes from not separating "how does an agent use a tool" from "how do two independent agents work together." Once that distinction is clear, the two stop looking like competitors and start looking like two layers of the same stack.
Two different jobs
| Protocol | Origin | What it connects |
|---|---|---|
| MCP (Model Context Protocol) | Anthropic, now under Linux Foundation | An agent to the tools and data it needs — a database, a search index, an internal API. Vertical integration. |
| A2A (Agent2Agent) | Google, donated to Linux Foundation in June 2025 | One agent to another independent agent, often across organizational boundaries — coordination, not tool access. Horizontal integration. |
MCP reached roughly 97 million monthly downloads by March 2026 — it's become the default way an agent reaches into a specific system to get context or take an action. A2A, meanwhile, passed 150 supporting organizations by its one-year mark in April 2026, with production deployments in supply chain, financial services, insurance, and IT operations, and integrations already live in Microsoft Azure AI Foundry and Copilot Studio, AWS Bedrock AgentCore, and Google Cloud.
The pattern in one line: MCP is how an agent reaches down into its own tools. A2A is how it reaches sideways to another agent it doesn't control.
Why this split matters for agentic commerce specifically
A buyer-agent and a seller-agent, by definition, belong to different organizations — a shopper's agent doesn't work for the merchant, and a merchant's inventory agent doesn't work for its suppliers. That's exactly the boundary A2A was built to cross: secure, structured communication between agents that don't share infrastructure or trust each other by default. Underneath that, each side still uses MCP internally — the merchant's agent uses MCP to query its own product catalog and inventory system, while A2A is the layer that lets it negotiate and transact with an external buyer's agent or a supplier's agent.
What "convergence" actually looks like
Neither protocol is trying to replace the other, and both now sit under the same Linux Foundation governance umbrella, which has done more to align the ecosystem in a year than competing standards usually manage in three. The practical takeaway for anyone building agent-ready commerce infrastructure: plan for both layers from the start rather than treating tool-access and agent-to-agent coordination as the same problem solved by the same protocol.