MCP Builder

AnthropicDevelopmentClaude Code

Plan, implement and evaluate MCP servers that give agents useful tools for external APIs.

View source

Illustrative MCP Builder workflow: API docs + agent tasks; example output includes search_records, list_files, create_note.

Install MCP Builder

Register Anthropic’s marketplace and install the example-skills plugin in Claude Code.

Register the marketplace

/plugin marketplace add anthropics/skills

Install the plugin

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

These commands install the corresponding skill set. Copying them does not install it; run them in Claude Code and confirm the plugin is enabled.

What this skill helps with

Anthropic’s MCP Builder skill is a development guide for Model Context Protocol servers. It covers Python and TypeScript implementations and judges tool design by whether an agent can accomplish useful tasks with the connected service.

When to use it

Use it when exposing an external API or service to an AI agent through MCP. It is intended for building a server, not simply installing or connecting an existing one.

What to bring

Bring the service’s API documentation, authentication requirements, available endpoints and the tasks the agent should perform. Include the intended client, language and local or remote transport.

What to expect

Expect a server implementation with clear tool names, validated inputs, focused responses, helpful errors and task-based evaluations. The tool list in the illustration is a fictional development example.

How the skill works

Research and plan

Study the MCP specification, SDK and target API. Choose tools that balance endpoint coverage with the workflows the agent needs.

Implement useful tools

Define typed input schemas and clear action-oriented names. Add pagination, concise responses and actionable failure messages.

Review, test and evaluate

The source’s four phases end with review and evaluations. Test tools against realistic tasks rather than treating successful startup as sufficient validation.

Related skills and guides

MCP Builder skill questions

Which languages does it cover?

The source includes TypeScript SDK and Python guidance, with TypeScript as its recommended default. Choose the stack that fits the server and deployment environment.

Is a skill itself an MCP server?

No. This skill supplies instructions and reference files for building a server. The server is a separate program that exposes callable tools.

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