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A2A vs MCP for Agent Integrations

A clear comparison of Agent2Agent (A2A) and Model Context Protocol (MCP), including when to use each in multi-agent systems.
A2AMCPagentsmulti-agent systemsintegrations

10 min read

Updated todayVerified recentlyInformation score 92

Key insights

Concrete technical or product signals.

  • MCP is app-to-tool/context; A2A is agent-to-agent.
  • The two protocols are complementary in larger agent architectures.
  • Protocol adoption does not remove the need for identity, authorization, and audit logs.

Use cases

Where this shines in production.

  • Choosing an integration strategy for enterprise assistant platforms.
  • Explaining why a remote specialist agent is not just another local function.
  • Designing multi-agent workflows where each agent keeps its own tools.

Limitations & trade-offs

What to watch for.

  • The ecosystem is still evolving, so implementation details and adoption may vary.
  • A protocol boundary does not automatically make delegated work trustworthy.

A2A vs MCP for Agent Integrations

A2A and MCP solve different integration problems.

MCP connects an AI application to external systems: tools, files, databases, search, prompts, and workflows. An MCP server exposes capabilities, and an MCP client consumes them.

A2A connects agents to other agents. It focuses on capability discovery, task management, messages, artifacts, and collaboration across agents that may be built with different frameworks or vendors.

Use MCP when the agent needs tools or data

Choose MCP when your assistant needs to query a database, read files, call an internal API, use search, or expose a repeatable workflow to several AI clients. MCP is the integration boundary between the AI client and external capabilities.

Use A2A when one agent delegates to another agent

Choose A2A when a planning agent needs to ask a specialized agent to complete a task, monitor its status, and receive artifacts. A2A's Agent Card, task lifecycle, and message parts are designed for agent-to-agent coordination.

Use both in larger systems

In a realistic enterprise workflow, a coordinator agent might use A2A to delegate tax analysis to a finance agent. That finance agent might use MCP servers to access policies, spreadsheets, and approval workflows.

Security checklist

Authenticate the remote agent or MCP server, authorize capabilities by user and task, log every delegation and tool call, validate artifacts before using them, and avoid giving a remote agent broad credentials just because it is reachable through a protocol.

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