Module 6 of 7
6. Protocols
The Two Protocols
MCP connects agents to tools; A2A connects agents to agents
MCP: Model Context Protocol
Agent ↔ Tools
Connects to
Search APIs
Databases (PostgreSQL, MongoDB)
File systems
Google Sheets, Slack, GitHub
Created by
Anthropic (open standard)
A2A: Agent-to-Agent Protocol
Agent ↔ Agent
Enables
Your agent hires a booking agent
Finance agent negotiates with vendor agent
Support agents escalate to specialist agents
Cross-organization agent collaboration
Created by
Google (open standard)
For agents to work across the open internet, they need standardized languages. Just as HTTP standardized how browsers talk to servers, MCP and A2A are standardizing how agents talk to tools and to each other. This module goes deep into both protocols.
Agent Protocol Landscape
Competing standards for agent interoperability
| Protocol | Org | Transport | Focus | Status |
|---|---|---|---|---|
| MCP | Anthropic | stdio / HTTP | Tool calling for AI agents | Production |
| OpenAPI | Linux Foundation | HTTP REST | API documentation and client generation | Mature |
| A2A | HTTP + SSE | Agent-to-agent communication | Early | |
| ACP | Cisco | HTTP | Enterprise agent collaboration | Draft |