# MCP Developer

Use when building, debugging, or extending MCP servers or clients that connect AI...

- Repository: https://github.com/Jeffallan/claude-skills (12164 stars)
- Category: Testing
- License: MIT
- Last updated: 2026-10-30
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add Jeffallan/claude-skills --skill mcp-developer -g -a claude-code -y`
Codex: `npx skills add Jeffallan/claude-skills --skill mcp-developer -g -a codex -y`
Cursor: `npx skills add Jeffallan/claude-skills --skill mcp-developer -g -a cursor -y`
Gemini CLI: `npx skills add Jeffallan/claude-skills --skill mcp-developer -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add Jeffallan/claude-skills`

## Description

Use when building, debugging, or extending MCP servers or clients that connect AI systems with external tools and data sources. Invoke to implement tool handlers, configure resource providers, set up stdio/HTTP/SSE transport layers, validate schemas with Zod or Pydantic, debug protocol compliance issues, or scaffold complete MCP server/client projects using TypeScript or Python SDKs.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# MCP Developer

Senior MCP (Model Context Protocol) developer with deep expertise in building servers and clients that connect AI systems with external tools and data sources.

## Core Workflow

1. **Analyze requirements**, Identify data sources, tools needed, and client apps
2. **Initialize project**, `npx @modelcontextprotocol/create-server my-server` (TypeScript) or `pip install mcp` + scaffold (Python)
3. **Design protocol**, Define resource URIs, tool schemas (Zod/Pydantic), and prompt templates
4. **Implement**, Register tools and resource handlers; configure transport (stdio/SSE/HTTP)
5. **Test**, Run `npx @modelcontextprotocol/inspector` to verify protocol compliance interactively; confirm tools appear, schemas accept valid inputs, and error responses are well-formed JSON-RPC 2.0. **Feedback loop:** if schema validation fails → inspect Zod/Pydantic error output → fix schema definition → re-run inspector. If a tool call returns a malformed response → check transport serialisation → fix handler → re-test.
6. **Deploy**, Package, add auth/rate-limiting, configure env vars, monitor

## Reference Guide

Load detailed guidance based on context:

| Topic | Reference | Load When |
|-------|-----------|-----------|
| Protocol | `references/protocol.md` | Message types, lifecycle, JSON-RPC 2.0 |
| TypeScript SDK | `references/typescript-sdk.md` | Building servers/clients in Node.js |
| Python SDK | `references/python-sdk.md` | Building servers/clients in Python |
| Tools | `references/tools.md` | Tool definitions, schemas, execution |
| Resources | `references/resources.md` | Resource providers, URIs, templates |

## Minimal Working Example

### TypeScript, Tool with Zod Validation

```typescript
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";

const server = new McpServer({ name: "my-server", version: "1.1.0" });

The rest: https://github.com/Jeffallan/claude-skills/blob/HEAD/skills/mcp-developer/SKILL.md