mcp-builder
Build MCP servers in Python with FastMCP. Define tools / resources / prompts, build the server, test locally, deploy to FastMCP Cloud or Docker. Use whenever the user mentions building an MCP server, exposing tools to LLMs, FastMCP, building a Claude integration, or troubleshooting FastMCP module-level server, storage, lifespan, middleware, OAuth, or deployment errors.
npx skills add jezweb/claude-skills --skill mcp-builder --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# MCP Builder Build a working MCP server from a description of the tools you need. Produces a deployable Python server using FastMCP. ## Workflow ### Step 1: Define What to Expose Ask what the server needs to provide: - **Tools** -- Functions Claude can call (API wrappers, calculations, file operations) - **Resources** -- Data Claude can read (database records, config, documents) - **Prompts** -- Reusable prompt templates with parameters A brief like "MCP server for querying our customer database" is enough. ### Step 2: Scaffold the Server ```bash pip install fastmcp ``` Create the server file. The server instance MUST be at module level: ```python from fastmcp import FastMCP # MUST be at module level for FastMCP Cloud mcp = FastMCP("My Server") @mcp.tool() async def search_customers(query: str) -> str: """Search customers by name or email.""" # Implementation here return f"Found customers matching: {query}" @mcp.resource("customers://{customer_id}") async def get_customer(customer_id: str) -> str: """Get customer details by ID.""" return f"Customer {customer_id} details" if __name__ == "__main__": mcp.run() ``` ### Step 3: Add Companion CLI Scripts (Optional) For Claude Code termi
- Workflow
- Step 1: Define What to Expose
- Step 2: Scaffold the Server
- Step 3: Add Companion CLI Scripts (Optional)
- Step 4: Test Locally
- Step 5: Pre-Deploy Checklist
- Step 6: Deploy
- Critical Patterns
- Module-Level Server Instance
- Type Annotations Required
- Error Handling
- Cloud-Ready Server Pattern
- Common Errors and Fixes
- Production Patterns
pip install fastmcp python server.py fastmcp dev server.py Opens inspector at http://localhost:5173 Hot reload, detailed logging, tool/resource inspection python server.py --transport http --port 8000 grep -q "^mcp = FastMCP\|^server = FastMCP\|^app = FastMCP" server.py git add . && git commit -m "Ready for deployment" git push -u origin main Visit https://fastmcp.cloud, connect repo, add env vars, deploy
What does the mcp-builder skill do?
Build MCP servers in Python with FastMCP. Define tools / resources / prompts, build the server, test locally, deploy to FastMCP Cloud or Docker. Use whenever the user mentions building an MCP server, exposing tools to LLMs, FastMCP, building a Claude integration, or troubleshooting FastMCP module-level server, storage, lifespan, middleware, OAuth, or deployment errors.
How do I install it?
Run `npx skills add jezweb/claude-skills --skill mcp-builder --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From jezweb/claude-skills, a repository with 954 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.