Episode 044: The Agent Stack Picks Its Three: MCP, A2A, AP2 — and What Six Protocols Still Don't Solve
The Agent Stack Picks Its Three: MCP, A2A, AP2 — and What the Six-Protocol Era Still Doesn't Solve A special-edition deep dive on the six wire-format specifications competing to define the agent stack — Model Context Protocol, Agent-to-Agent, AG-UI, A2UI, Agent Payments Protocol, and x402. By mid-2026, three of them are pulling ahead as load-bearing infrastructure. The other three are smaller stories, and the most consequential parts of the picture are the gaps that none of the six, individually, solves. ...