MCP (Model Context Protocol).

MCP is how an AI agent talks to and acts inside your other apps and data, like Stripe, Gmail, or Notion. Anthropic created it as a standard, so every tool speaks to the agent the same way.

The cleanest way to think about it is USB for AI. Before USB, every device had its own weird plug. USB turned all of that into one port, so anything works. MCP does that for tools. Another way to picture it: Claude speaks English, all these other tools speak different languages, and MCP is the translator sitting in between.

There's a catch once you're building. MCP is context-heavy. Every Tool calls eats into your Context window, and that adds up fast when you have a lot of tools connected. For terminal agents I now often reach for a CLI / Terminal instead. It does the same job leaner.