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Protocols

Open protocols for connecting agents, tools, resources, and other agents.

How To Evaluate Entries​

Each entry in this family should make the following points clear:

  • What the convention is.
  • Where the file, URL, or protocol surface normally lives.
  • When a team should use it.
  • Adoption evidence from a public spec, canonical docs, or active ecosystem use.
  • Which example illustrates the convention, if one exists.
  • Related conventions that solve adjacent problems.

Registry Entries​

Model Context Protocol (MCP)​

An open protocol for connecting AI models to external tools, APIs, and data sources. Described as "USB-C for AI models." Created by Anthropic and donated to the Agentic AI Foundation (Linux Foundation) in December 2025, alongside AGENTS.md and Goose.

MCP defines a standard interface between an LLM host (Claude, Cursor, VS Code, etc.) and MCP servers that expose tools, resources, and prompts. The protocol replaced dozens of fragmented tool-calling integrations across the industry.

Agent Cards​

A proposed standard for agents to expose their identity, capabilities, and trust level to other agents in multi-agent systems. Part of the broader push for agent interoperability. Referenced in the A2A (Agent-to-Agent) protocol from Google.