mcp-builder Skill: Build MCP Servers with Claude

/plugin install example-skills@anthropic-agent-skills

mcp-builder is a guide for creating high-quality MCP servers that let LLMs interact with external services through well-designed tools. Use it when you want Claude to wrap an API or internal service as an MCP server in Python (FastMCP) or Node/TypeScript (MCP SDK).

What it does

The skill runs a four-phase workflow:

1. Research and planning: study the target API and design tools around real workflows, not one tool per endpoint.
2. Implementation: build the server using the language-specific guides bundled with the skill.
3. Review and test: check quality and behavior.
4. Create evaluations: write realistic questions that test whether an LLM can use the tools to get answers.

It loads reference files on demand: core MCP docs, SDK docs, and per-language guides, which keeps the main instructions short.

Install

/plugin marketplace add anthropics/skills
/plugin install example-skills@anthropic-agent-skills

Or copy skills/mcp-builder into ~/.claude/skills/. For where skills live and how they load, see the skills guide.

Example usage

Build an MCP server in TypeScript for our internal ticketing REST API. Start with a plan
Use FastMCP to wrap the weather API in two or three well-designed tools
Write evaluation questions for the MCP server in ./mcp/billing

Tips

• Test with MCP Inspector before connecting the server to Claude.
• Keep tool count and descriptions tight; every tool definition costs context in each session.
• Look at the MCP reference servers for small, readable examples.

Source and license

Part of anthropics/skills, licensed Apache-2.0 (see LICENSE.txt in the skill folder). Anthropic provides these skills for demonstration and education; review generated servers before deploying them.