What the tech

Search

Browse topics

/ opens search from anywhere. Esc closes it.

Tools
What the tech
Get the newsletter

mcp-builder: a Claude Code skill by Anthropic

Official

For developers turning an API or service into tools Claude can call through MCP. Skip it if you only want to use a server someone else already built.

Copy install command View the source
Score
88of 100
Rank
#16of 239
Installs
14Kon skills.sh
Security
Mixed 5 scanners
Updated
2026
Context
~72tokens always

Install

npx skills add https://github.com/anthropics/skills --skill mcp-builder

Run it in your terminal. View the source

Using the Claude app rather than Claude Code? You can add a skill there too. How to add it in the app

What does mcp-builder do?

mcp-builder is a skill that walks Claude through writing an MCP server, the kind of program that gives an AI model tools for an outside API or service. It runs in four phases. First Claude studies the MCP spec, the SDK docs and the target API, and plans which endpoints to cover. Second it builds the server, with TypeScript SDK v2 as the default and Python FastMCP as the alternative, using Zod or Pydantic schemas, pagination and error messages that point to a fix. Third it compiles the project and checks it with MCP Inspector. Last it writes ten read-only test questions with verified answers in an XML file.

When should you use mcp-builder?

Use it when

  • Connecting Claude to your company's internal API
  • Wrapping a third-party service that has no MCP server yet
  • Moving an old TypeScript MCP server to SDK v2

Skip it when

  • A connector for the service already does what you need
  • You are not comfortable reading TypeScript or Python code

What it needs and what it can touch

You need

  • Node.js for TypeScript, or Python for FastMCP
  • Access to the API of the service you want to connect

What it can do

  • Fetches MCP and SDK documentation from the web
  • Writes server code in your project
  • Runs build and test commands, including npx tools

From reading its instructions, not from running it.

Why it scores 88

Strongest on upkeep (100 of 100), weakest on adoption (70).

  • Adoption35 points 70
  • Upkeep20 points 100
  • Trust20 points 97
  • Quality15 points 100
  • Reader answers10 points Not enough answers yet, so this does not count

How the formula works

Is mcp-builder safe to install?

At least one scanner raised a medium warning. Read the results below. Scanners often miss what other scanners catch, and a skill can change after a scan. Read its source before you install it.

ScannerResultDate
Gen Agent Trust HubPassedOct 28, 2026
SocketPassedOct 28, 2026
SnykMedium riskOct 28, 2026
RunlayerLow riskFeb 26, 2026
ZeroLeaksPassedApr 16, 2026

Details

Installs
140,053
Repository stars
192,526
Last repository change
Tokens always loaded
about 72
Tokens when used
about 2,683
License
Apache-2.0
Data confidence
High

Alternatives to mcp-builder

All skills for this job