Four-phase workflow for creating MCP servers: research and planning, implementation, review and testing, and evaluation. Quality is measured by how well an LLM can complete real tasks with the tools.
What it does
Where mcp-builder runs and what it adds, from its documentation
Balances full API coverage against workflow tools
Guides tool naming and discoverability
Covers Python FastMCP and TypeScript MCP SDK
Walks through four phases from research to evaluation
When to use it
Good fit
Wrapping an external API as an MCP server
Reviewing the tool design of an existing MCP server
Not for
Using an existing MCP server (this is for building)
How to install mcp-builder
Register the marketplace in Claude Code: /plugin marketplace add anthropics/skills
Install the bundle that contains it (document-skills or example-skills): /plugin install example-skills@anthropic-agent-skills
Or copy the skill folder to ~/.claude/skills/mcp-builder/ (personal) or .claude/skills/mcp-builder/ (project)
Mention the task in a prompt; Claude loads the skill automatically when the SKILL.md description matches
Permissions and security
What it can access
Instructions loaded into Claude's context; any scripts it bundles run through Claude Code's normal tool permissions (shell, file edits)
Security notes from the maintainers
Anthropic repo disclaimer: skills are provided for demonstration and educational purposes; behavior in Claude may differ
Review the source before granting an agent access to credentials or production systems. We document what the maintainers state; we do not audit code.
Limitations
Repo README says implementations are examples and may differ from what Claude.ai provides
How do I install the mcp-builder skill in Claude Code?
Add the marketplace with /plugin marketplace add anthropics/skills and install the bundle containing it, or copy skills/mcp-builder into ~/.claude/skills/. source
When does Claude use the mcp-builder skill?
Claude loads it automatically when the request matches the description field in its SKILL.md frontmatter. source
Is the mcp-builder skill official?
Yes, it is published in Anthropic's anthropics/skills repository. source
