MCP — Model Context Protocol
This is why AI tools suddenly started working together — and what it means for what you build
What is MCP — Model Context Protocol
For most of AI's recent history, every tool was an island.
You had an AI assistant. You had your calendar, your code editor, your database, your email, your documentation. They did not talk to each other. Every integration was custom work — one team writing a specific connector for one specific tool, for one specific AI model. Nothing transferred. Nothing composed. You built everything from scratch every time.
In late 2024, Anthropic published an open standard called the Model Context Protocol. MCP is a shared language that lets AI models connect to external tools, data sources, and services using a consistent interface — one that any tool can implement and any model can use.
The shift it made
Before MCP: to connect Claude to your database, you wrote a custom integration. To connect it to your file system, another integration. To connect it to your calendar, another. None of it worked with GPT-4o. None of it worked with Gemini. Custom code everywhere.
After MCP: a tool that implements the MCP standard works with any model that supports MCP. Build the connector once. Use it everywhere. Share it with others. The ecosystem compounds.
The number that makes it real
MCP support is now a tracked capability on sourc.dev. Claude 3.5 Sonnet supports MCP. Verified March 2026. The number of publicly available MCP servers — pre-built connectors for common tools — has grown from zero at launch to hundreds within months.
Why this matters to you
If you are building AI applications that need to access external data or take actions in external systems — and most useful AI applications do — MCP reduces the integration work significantly.
Instead of building a custom connector for your database, check whether an MCP server for it already exists. Instead of maintaining a one-off integration, use a standard that the broader ecosystem maintains.
It does not eliminate integration work. It reduces the amount that is uniquely yours to build.
Verified March 2026 · Source: Anthropic MCP documentation, modelcontextprotocol.io