What Is the Model Context Protocol (MCP)?
The Model Context Protocol (MCP) is an open standard created by Anthropic for building secure, two-way connections between AI assistants and external data sources, tools, and services. MCP replaces fragmented, custom integrations with a universal protocol — like a "USB-C for AI" — allowing any MCP-compatible AI system to connect to any MCP-compatible data source.
Why MCP Was Created
Before MCP, connecting AI to external tools required custom implementations for each combination of AI model and data source. This created:
- Integration sprawl — N models × M tools = N×M custom connectors
- Fragmented ecosystems — Each AI provider had its own integration approach
- Security risks — Inconsistent authentication and authorization
- Maintenance burden — Custom connectors required ongoing upkeep
MCP solves this with a single, standardized protocol that any AI system can implement.
How MCP Works
Architecture
MCP uses a client-server architecture:
- MCP Hosts — AI applications that need to access external data (Claude Desktop, IDEs, AI agents)
- MCP Clients — Protocol clients within the host that manage connections to servers
- MCP Servers — Lightweight services that expose specific data sources or tools through the standardized protocol
Key Capabilities
| Capability | Description |
|---|---|
| Resources | Expose data from files, databases, or APIs for the AI to read |
| Tools | Define actions the AI can invoke (search, create, update, delete) |
| Prompts | Provide reusable prompt templates with context |
| Sampling | Allow servers to request LLM completions through the client |
Protocol Flow
- AI host connects to one or more MCP servers
- Servers declare their available resources and tools
- When the AI needs external data, it sends a request via MCP
- The server processes the request and returns results
- The AI incorporates the data into its response or workflow
Adoption
MCP has been adopted across the AI industry:
- Anthropic — Claude Desktop and Claude Agent SDK
- OpenAI — Integrated MCP support
- Google — MCP compatibility in Gemini ecosystem
- Microsoft — MCP support in development tools
- Community — Thousands of open-source MCP servers for tools like GitHub, Slack, Google Drive, PostgreSQL, and more
MCP vs. Function Calling
| Feature | Function Calling | MCP |
|---|---|---|
| Standard | Provider-specific | Universal open standard |
| Discovery | Manual schema definition | Automatic capability discovery |
| Security | Varies by implementation | Built-in auth and permissions |
| Ecosystem | Tied to one provider | Cross-provider compatibility |
| Composability | Limited | Multiple servers can be combined |
Building with MCP
MCP Servers
Expose your data or tools through the MCP protocol. SDKs are available for TypeScript, Python, and other languages.
MCP Clients
Build AI applications that can connect to any MCP server, automatically discovering and using available tools and resources.