mcp-builder

1# MCP Builder
2 
3Build a working MCP server from a description of the tools you need. Produces a deployable Python server using FastMCP.
4 
5## Workflow
6 
7### Step 1: Define What to Expose
8 
9Ask what the server needs to provide:
10 
11- **Tools** -- Functions Claude can call (API wrappers, calculations, file operations)
12- **Resources** -- Data Claude can read (database records, config, documents)
13- **Prompts** -- Reusable prompt templates with parameters
14 
15A brief like "MCP server for querying our customer database" is enough.
16 
17### Step 2: Scaffold the Server
18 
19```bash
20pip install fastmcp
21```
22 
23Create the server file. The server instance MUST be at module level:
24 
25```python
26from fastmcp import FastMCP
27 
28# MUST be at module level for FastMCP Cloud
29mcp = FastMCP("My Server")
30 
31@mcp.tool()
32async def search_customers(query: str) -> str:
33    """Search customers by name or email."""
34    # Implementation here
35    return f"Found customers matching: {query}"
36 
37@mcp.resource("customers://{customer_id}")
38async def get_customer(customer_id: str) -> str:
39    """Get customer details by ID."""
40    return f"Customer {customer_id} details"
41 
42if __name__ == "__main__":
43    mcp.run()
44```
45 
46### Step 3: Add Companion CLI Scripts (Optional)
47 
48For Claude Code terminal use, add scripts alongside the MCP server:
49 
50```
51my-mcp-server/
52├── src/index.ts          # MCP server (for Claude.ai)
53├── scripts/
54│   ├── search.ts         # CLI version of search tool
55│   └── _shared.ts        # Shared auth/config
56…