What Is MCP?
The Model Context Protocol (MCP) is an open standard by Anthropic for connecting AI assistants to external data sources and tools. Think of it as USB-C for AI — one protocol that works everywhere.
Why MCP Matters
Before MCP, every AI integration was custom. Each tool needed its own plugin, API wrapper, and configuration. MCP standardizes this.
Architecture
- MCP Host: The AI application (e.g., Claude Desktop, Cursor).
- MCP Server: Exposes tools and resources via the protocol.
- MCP Client: Connects the host to servers.
Key Concepts
- Tools: Functions the AI can call (search, create file, query database).
- Resources: Data the AI can read (files, database records, API responses).
- Prompts: Reusable prompt templates shared between applications.
Building an MCP Server
1. Define your tools with JSON schemas.
2. Implement the MCP protocol (REST or stdio transport).
3. Register capabilities (tools, resources, prompts).
4. Test with MCP Inspector or Claude Desktop.
Ecosystem
- GitHub: MCP server for repositories and issues.
- PostgreSQL: MCP server for database queries.
- Slack: MCP server for messaging and channels.
- Filesystem: MCP server for local file access.
For Developers
- MCP SDKs available in TypeScript and Python.
- Follow the specification at modelcontextprotocol.io.
- Community servers growing rapidly — hundreds available.
Building Your First MCP Server
Here’s a minimal example using the TypeScript SDK:
```typescript
import { McpServer } from “@mcp/sdk”;
const server = new McpServer({ name: “my-tool”, version: “1.0.0” });
server.tool(“search”, { query: z.string() }, async ({ query }) => {
const results = await searchDatabase(query);
return { content: [{ type: “text”, text: JSON.stringify(results) }] };
});
```
Security Considerations
- Authentication: MCP servers should require API keys or OAuth tokens. Never expose servers publicly without auth.
- Input validation: Validate all tool inputs against schemas. MCP doesn’t sanitize inputs automatically.
- Rate limiting: Implement rate limits to prevent abuse. A typical limit is 100 requests/minute per client.
- Audit logging: Log all tool invocations for debugging and compliance.
MCP vs Traditional APIs
MCP adds semantic understanding—the AI knows what each tool does and when to use it. Unlike REST APIs where the developer hardcodes integration logic, MCP lets the AI decide which tools to call based on context. This makes MCP ideal for agentic workflows where the AI needs to dynamically choose actions.