# MCP Builder

> MCP server development for AI agents. Designs tool schemas, implements Python/TypeScript servers, creates evaluation tests. Use when user asks to build MCP server, create tool integration, or develop Claude plugins. Supports GitHub/Notion/Slack integrations.

- Skill: `jochenyang/mcp-builder` (Agent Skill, multi-file: 10 files)
- Install (CLI): `npx skillmds@latest add jochenyang/mcp-builder`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jochenyang/mcp-builder/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: JochenYang (https://skillmd.com/u/jochenyang)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/jochenyang/mcp-builder

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# MCP Server Development Tool

Build high-quality Model Context Protocol servers to provide external tool capabilities for AI agents.

## Core Capabilities

- MCP protocol understanding and server architecture design
- Python/TypeScript SDK implementation
- Tool schema design for AI agents
- Evaluation test creation and validation

## Tech Stack

| Language   | SDK                | Validation  | Runtime     |
|------------|--------------------|-------------|-------------|
| Python     | MCP Python SDK     | Pydantic v2 | asyncio     |
| TypeScript | MCP TypeScript SDK | Zod         | Node.js 18+ |

## Executable Tools

The following scripts can be run directly without reading source code:

- `scripts/evaluation.py` - Run MCP server evaluation tests
- `scripts/connections.py` - Test server connection status

## Design Principles

1. **Workflow-Oriented**: Build complete task tools, not simple API wrappers
2. **Optimize Context**: Return high-signal information, avoid data dumping
3. **Actionable Errors**: Error messages guide agents to correct usage
4. **Evaluation-Driven**: Create evaluation scenarios early, iterate based on agent feedback

## Boundaries

Focus on MCP server development and tool design, not third-party API development or client integration.

## When NOT to Use

- Writing general business logic code → use `developer`
- Frontend UI development → use `frontend-design`
- API design → use `api-designer`
- Database schema design → use `database-engineer`
- Product planning or requirements → use `product-manager`

## Detailed References

- `./workflows/mcp-development.md` - Complete development workflow
- `./guides/mcp_best_practices.md` - MCP best practices
- `./guides/python_mcp_server.md` - Python implementation guide
- `./guides/node_mcp_server.md` - TypeScript implementation guide
- `./guides/evaluation.md` - Evaluation creation guide

## Escalation Rules

Pause and ask the owner before:

- exposing tools that have overly broad permissions or weak schema boundaries
- expanding server scope into generic third-party API integration work
- shipping an MCP interface without at least a basic evaluation or validation path

## Final Output Contract (MANDATORY)

Every use of this skill should end with:

1. `Skill Fit` - why an MCP server or tool design solution is needed
2. `Primary Deliverable` - server design, tool schema, or implementation plan
3. `Execution Evidence` - guides used, files changed, and evaluation steps prepared
4. `Risks / Open Questions` - permission, schema, or agent-usage concerns
5. `Next Action` - the next build, test, or review step