Architecture AI Updates: July 20, 2026

1. Comparing MCP, A2A, and ACP as Distinct Layers of Agent Communication

ByteByteGo. The piece separates three agent communication protocols by the boundary each one crosses, positioning them as complementary layers rather than competitors. Model Context Protocol handles agent-to-tool communication, where an embedded client routes requests to servers that execute tool calls within a single system, while Agent-to-Agent lets agents discover peers through published Agent Cards and delegate structured tasks across distributed deployments. It also notes that the REST and SSE-oriented Agent Communication Protocol has since merged into the A2A standard, framing tool access and peer-to-peer coordination as separate architectural concerns. Source