22 min read
MCP vs A2A: How AI Agent Protocols Work Together in 2026
Compare MCP and A2A, see where each protocol fits, and use a practical architecture, security checklist, and eight prompts to design agent systems.
- MCP connects an AI application to tools, data, prompts, and other context; A2A lets independent agents discover one another, exchange messages, manage tasks, and return artifacts.
- The protocols are complementary. A multi-agent product can use A2A at the agent boundary and MCP inside each agent to reach its approved tools and information.
- Protocol adoption does not create trust by itself. Identity, authorization, data classification, approval gates, observability, and evaluation remain application responsibilities.