What is the difference between MCP and A2A?
MCP connects an AI application or agent to tools and data; A2A connects agents to other agents, including agents built by different teams or vendors. The A2A project describes the two as complementary rather than competing: an agent might use MCP to reach a database and A2A to delegate part of a task to another organisation's agent. Most single applications need MCP or plain function calling long before they need A2A.
- Published
- 22 October 2026
- Sources checked
- 22 October 2026
- From
- Kramiva
01
Side by side
- Purpose: MCP is agent-to-tool; A2A is agent-to-agent
- Counterpart: an MCP server exposes tools, resources and prompts; an A2A agent exposes skills described in an Agent Card
- Unit of work: MCP calls a tool and gets a result; A2A creates a Task with a lifecycle that can run long and return Artifacts
- Transport: both use JSON-RPC 2.0; A2A runs over HTTP(S)
- Governance: MCP has its own open specification; A2A started at Google and is now a Linux Foundation project with a multi-vendor technical steering committee
02
How they fit together
The A2A documentation gives the division plainly: MCP is for an agent's tools and data, A2A for communication between agents that may be opaque to each other — neither needs to know how the other is built. An agent can be an A2A server to its peers and an MCP client to its tools at the same time.
03
An illustrative example
A travel company's booking agent uses MCP servers to read its own inventory and pricing. To arrange airport transfers, it sends an A2A task to a partner company's agent, which works on the request in its own systems and returns a confirmation as an artifact. Neither company exposes its internals to the other.
04
Trade-offs
A2A solves a real problem — agents from different organisations working together — that most teams do not yet have. Adopting it adds network calls, authentication between agents and a new attack surface. If every agent lives inside one application, framework-level hand-offs are simpler.
Where Kramiva fits
Kramiva's AI work connects to the systems a client already runs and hands over the source code and documentation, so the client's own team can see and maintain how each connection works.
Sources
- Agent2Agent (A2A) Protocol documentation — A2A Project (Linux Foundation)
- A2A key concepts — A2A Project (Linux Foundation)
- Model Context Protocol specification — Model Context Protocol
Accessed 22 October 2026. Kramiva is not affiliated with these publishers.
Related questions
Tell us what you are building.
A short brief gets you a real reply from a founder within one business day — an honest read on fit, scope, and budget.