Guides · Updated 2026-10-17
MCP vs A2A: what each protocol does and when to use both
Short answer: use MCP to give one agent its tools (a GitHub repo, a database, a search API). Use A2A when your agent needs to hand work to *another* agent built by someone else. The A2A project itself says the two are complementary.
How do MCP and A2A compare side by side?
| MCP | A2A | |
|---|---|---|
| Connects | an AI app to tools, data and workflows | an agent to other agents |
| Typical job | read files, query a database, call an API | delegate a sub-task, exchange results |
| Origin | introduced by Anthropic | developed by Google, donated to the Linux Foundation |
| License / governance | open-source standard | Apache 2.0, Technical Steering Committee |
What is MCP, in one paragraph?
The MCP docs call it "an open-source standard for connecting AI applications to external systems" and compare it to a USB-C port for AI apps. An MCP server exposes tools; a client such as Claude, ChatGPT, VS Code or Cursor connects to it.
What is A2A, in one paragraph?
A2A is "an open standard for seamless communication and collaboration between AI agents." Agents can delegate sub-tasks and coordinate without sharing their internal memory, tools or proprietary logic. The A2A docs also say what it is *not*: not an agent framework, not a tool-call protocol, and not a replacement for MCP.
Which should you use?
- One agent, many tools: MCP. Start with the best MCP servers or read what an MCP server is.
- Several agents from different teams or vendors: add A2A on top.
- Many builds use both. See real setups.
Which tools in our directory relate to this, and how do they compare?
| Score | Tool | Type | Host |
|---|---|---|---|
| pending | GitHub MCP Server (official) GitHub's official MCP server. Remote endpoint used in Claude Code's docs with a GitHub personal access token. | MCP | api.githubcopilot.com |
| pending | Notion MCP (official) Official Notion MCP server for connecting MCP clients to your Notion workspace. | MCP | mcp.notion.com |
| pending | Atlassian Rovo MCP Server (official) Official remote MCP server for Atlassian: connect Jira, Confluence, Jira Service Management, Bitbucket and Com | MCP | mcp.atlassian.com |
| pending | Linear MCP (official) Linear's official remote MCP server for issues, projects and comments. | MCP | mcp.linear.app |
| pending | Playwright MCP (official, Microsoft) MCP server that provides browser automation using Playwright, letting LLMs interact with web pages through str | MCP | github.com |
| pending | Stripe MCP (official) Stripe's official remote MCP server for working with the Stripe API and docs. | MCP | mcp.stripe.com |
| 81 | LocalMark Agent Directory Search public A2A agents and inspect read-only Agent Card and endpoint checks. | MCP | localmark.ai |
| 81 | Nefesh — Real-Time Human State Awareness for AI Fuses biometric signals into a stress score (0-100) for AI adaptation. MCP + A2A native. | MCP | mcp.nefesh.ai |
| 57 | Delx MCP Server Agent operations platform with 20+ tools for AI agents. Dual-protocol MCP + A2A support, session memory, mood | MCP · auth | server.smithery.ai |
| 46 | LangSmith Traced OpenAI Agent LangSmith Traced OpenAI Agent: composes langchain-core + langchain-openai + langsmith + openai — orchestration | MCP · auth | server.smithery.ai |
What else do people ask?
What is the difference between MCP and A2A?
MCP (Model Context Protocol) standardizes how an AI application connects to tools, data and workflows. A2A (Agent2Agent) standardizes how independent agents discover each other, delegate tasks and share results. The A2A project describes them as complementary, not competitors.
Is A2A a replacement for MCP?
No. The A2A docs say explicitly that A2A is not a replacement for MCP; MCP is agent-to-tool and A2A is agent-to-agent.
Who maintains A2A?
A2A was originally developed by Google and donated to the Linux Foundation. Per its site, a Technical Steering Committee with representatives from AWS, Cisco, Google, IBM Research, Microsoft, Salesforce, SAP and ServiceNow maintains it, under the Apache 2.0 license.
Which apps support MCP?
The MCP docs list AI assistants like Claude and ChatGPT and development tools like Visual Studio Code and Cursor among supporting clients.
Sources
- Model Context Protocol: What is MCP?
- Anthropic: Introducing the Model Context Protocol
- A2A Protocol (official site)
More guides → · Real agent setups →
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