What is MCP?
Model Context Protocol, explained.
MCP is an open standard that lets AI assistants like Claude connect to databases, APIs, file systems, and other tools in real time. Think of it as a universal plug for AI — one standard that works across any tool and any AI client that supports the protocol.
The problem MCP solves
AI assistants are powerful at reasoning and generating text, but they are isolated from the real world by default. Claude can write code, but it cannot run it. It can discuss your database, but it cannot query it. Every time you want an AI to interact with a real system, someone has to build a custom, one-off integration.
This is the problem MCP solves. Instead of every AI tool and every external service building a bespoke integration, MCP defines one standard protocol. A server built once works with any MCP-compatible AI client — Claude today, a different model tomorrow.
How MCP works
MCP has three parts:
MCP Host
The AI application you use — Claude Desktop, Cursor, or another client. The host manages connections to MCP servers and routes the AI's tool calls.
MCP Server
A small program (usually running locally on your machine) that exposes one or more "tools" — functions the AI can call. A database MCP server might expose a run_query tool. A file system server might expose read_file and write_file.
External Resource
The actual system the server connects to — a database, an API, a file on your disk, a browser, or any other service.
When you ask Claude "What are the last 10 orders in my database?", Claude sends a run_query call to the database MCP server, which executes the SQL, and returns the results back to Claude — all within a single conversation turn.
What can you do with MCP?
MCP servers exist for hundreds of use cases. Here are some of the most popular:
- Query a PostgreSQL or SQLite database with natural language
- Read, write, and search files on your local machine
- Control a web browser — navigate, scrape, and fill forms
- Search GitHub, create issues, and manage pull requests
- Send Slack messages and read channel history
- Query your calendar, create events, and check availability
- Run terminal commands and interact with your dev environment
- Access vector databases for semantic search and RAG workflows
Is MCP safe?
MCP servers are small programs that run with whatever permissions you grant them. A file system server can only read and write files in the directories you explicitly allow. A database server only has the access your database user account has.
All servers listed on MCPCMD link to their public GitHub source code so you can review what they do before running them. Stick to servers from authors you trust and review the permissions each server requests.
How to install your first MCP server
- 1
Install Claude Desktop
Download the Claude Desktop app from anthropic.com. This is your MCP host — the app that manages server connections.
- 2
Choose a server from MCPCMD
Browse the directory and find a server that fits your use case. Each server page shows the install command and the config snippet you need.
- 3
Run the install command
Open a terminal, paste the install command (usually starting with npx or pip), and press Enter.
- 4
Add the server to your Claude config
Copy the JSON config snippet from the server page and add it to your claude_desktop_config.json file. Save the file and restart Claude Desktop.
- 5
Start using it
Open a new conversation in Claude Desktop. You can now ask Claude to use the tools the server provides.
Ready to explore MCP servers?
Browse 1000+ MCP servers across databases, APIs, developer tools, and more.
Common questions
Do I need to know how to code to use MCP servers?
No. Most MCP servers are installed with a single copy-paste command in your terminal. If you can follow step-by-step instructions, you can install and use an MCP server. Some advanced servers may require an API key from a third-party service, but the process is usually well-documented.
Is MCP only for Claude?
No — MCP is an open standard, and support is growing. Claude Desktop and the Claude API were the first to adopt it, but tools like Cursor, Cline, Zed, and others now support MCP as well. Any AI client that implements the protocol can use any MCP server.
Are MCP servers free?
The vast majority of MCP servers listed on MCPCMD are free and open source. Some may require a paid API key from a third-party service (for example, a server that connects Claude to a paid SaaS product), but the server software itself is typically free.
Can I build my own MCP server?
Yes. Anthropic publishes an open SDK for building MCP servers in TypeScript and Python. The protocol is well-documented and the community has built servers for hundreds of use cases. If you have a tool or data source you want Claude to access, you can build a custom server.
What is the difference between MCP and plugins or function calling?
Function calling lets an AI model call a specific function defined at inference time — it is tightly coupled to a single model provider. MCP is a separate, model-agnostic protocol that defines a standard way for AI clients to discover and call tools at runtime. Think of function calling as a specific API call, and MCP as a universal adapter layer.