What is MCP (Model Context Protocol)?

MCP (Model Context Protocol) is an open standard released by Anthropic in late 2024 that lets LLMs connect to tools, databases, and apps through a unified protocol — avoiding the need for custom integrations for every model × tool pair.

Why MCP?

Before MCP:

• Every LLM (Claude, GPT, Gemini) had its own function-calling syntax
• Every tool (Slack, GitHub, Notion) needed its own integration code
• Number of integrations = N models × M tools (a lot!)

With MCP:

• A tool implements a single MCP server → any LLM that supports MCP can use it
• Number of integrations: N + M instead of N × M

Roles

┌─────────────┐     MCP protocol     ┌─────────────┐
│ MCP Client  │ ←──────────────────→ │ MCP Server  │
│ (LLM apps)  │   (tool/data calls)  │ (tool side) │
└─────────────┘                      └─────────────┘

• Client: app that calls the LLM (Claude Desktop, Cursor, Claude Code, …)
• Server: app that exposes capabilities (Slack server, Postgres server, Filesystem server)

Available MCP servers (2026)

• Filesystem: read/write local files
• Postgres / SQLite: query a database
• GitHub: create issues, read PRs, search code
• Slack / Discord: send/read messages
• Brave Search: search the web
• Puppeteer: drive a browser

→ One install command, and Claude Code can use it instantly.

When should you use MCP?

✅ Building an agent with many tools — no need to code a wrapper for each ✅ You want to share tool integrations across the team ✅ You use multiple LLM clients (Claude Desktop at home, Cursor at work)

❌ You only need one simple tool → plain function calling is usually enough ❌ Highly custom internal tooling → it may be faster to code direct integration

Quick setup (Claude Desktop)

claude_desktop_config.json:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/me/Documents"]
    }
  }
}

Restart Claude → Claude can now read/write files in /Users/me/Documents.

Adoption

By mid-2026: Claude, OpenAI, and a number of IDEs and apps support MCP. It’s gradually becoming the de facto standard for tool use.

Related

• AI Agent
• Function Calling