---
title: "MCP and agent protocols"
type: "topic"
url: "https://aifordevs.org/topics/mcp"
markdown: "https://aifordevs.org/topics/mcp.md"
publisher: "AI for Devs"
license: "https://aifordevs.org/reuse"
attribution: "Credit AI for Devs and link to https://aifordevs.org/topics/mcp"
---

# MCP and agent protocols

The protocols that connect models to tools and to each other. What an MCP server exposes, how clients discover it, and how to secure it.

## Articles

- [What is an AI agent? The loop in code, and where it fails](https://aifordevs.org/articles/what-is-an-ai-agent.md): What is an AI agent? A tested agent loop in TypeScript, run offline against a scripted model, with traces of runaway loops, tool errors, and token growth. (2026-11-08)
- [What is an MCP server? Build and test one in TypeScript](https://aifordevs.org/articles/build-an-mcp-server.md): What is an MCP server? Build a tested TypeScript one with a confirmed write tool, debug it with MCP Inspector, and apply the spec's security requirements. (2026-11-08)

## Glossary terms

- [A2A](https://aifordevs.org/glossary/a2a.md): A2A (Agent2Agent) is an open protocol, introduced by Google in April 2025, that lets agents built by different vendors discover each other, exchange tasks, and stream results. MCP connects an agent to tools and data, while A2A connects agents to other agents.
- [MCP](https://aifordevs.org/glossary/mcp.md): MCP (Model Context Protocol) is an open protocol, introduced by Anthropic in November 2024, that standardizes how AI applications connect to tools and data. A host application runs MCP clients that talk to MCP servers over JSON-RPC, using stdio for local servers or Streamable HTTP for remote ones.
- [MCP server](https://aifordevs.org/glossary/mcp-server.md): An MCP server is a program that exposes tools, resources, and prompts to any MCP-compatible client. Write one server for your API or database, and every MCP host, from coding agents to chat apps, can use it.
- [Tool calling](https://aifordevs.org/glossary/tool-calling.md): Tool calling is a model returning a structured request to run a function you defined, with arguments, instead of plain text. Your code runs the function and sends the result back, which is how an agent loop reaches systems outside the model.

## Platforms

- [Bifrost](https://aifordevs.org/platforms/bifrost.md): Open-source AI gateway written in Go, with one API for many providers plus failover, caching, and governance.
- [LiteLLM](https://aifordevs.org/platforms/litellm.md): Python SDK and proxy server that call many providers through the OpenAI format.
- [Cloudflare AI Gateway](https://aifordevs.org/platforms/cloudflare-ai-gateway.md): Managed gateway on Cloudflare's network with caching, rate limiting, retries, and analytics.