MCP App Builder

by fazxes

MCP App Builder is an AI Engineering skill for Claude Code, published by fazxes in Claude-code.

234 stars216 forkson fazxes/Claude-codeAdded 2026/09/03Repository updated 2026/04/03

View source on GitHub Download repo ZIP

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Install in seconds

Install MCP App Builder

Copy MCP App Builder into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/fazxes/Claude-code/tree/main/stubs/downloads/official-plugins/marketplaces/claude-plugins-official/plugins/mcp-server-dev/skills/build-mcp-app ~/.claude/skills/build-mcp-app

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/fazxes/Claude-code.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: stubs/downloads/official-plugins/marketplaces/claude-plugins-official/plugins/mcp-server-dev/skills/build-mcp-app/SKILL.md in fazxes/Claude-code
Installs to: ~/.claude/skills/build-mcp-app
Collection: One of 25 skills cataloged from this repository
Category: AI Engineering — 2793 skills

What MCP App Builder does

MCP App Builder shows how to add interactive widgets to an MCP server, such as forms, pickers, confirmations, and live displays. Use it when you need inline UI in chat after deciding the base server architecture.

MCP App Builder is cataloged under AI Engineering on DirSkills. MCP App Builder comes from a repository tagged agentic, ai, anthropic, bun and claude.

Documentation

README

Excerpt

Build an MCP App (Interactive UI Widgets)

An MCP app is a standard MCP server that also serves UI resources — interactive components rendered inline in the chat surface. Build once, runs in Claude and ChatGPT and any other host that implements the apps surface.

The UI layer is additive. Under the hood it's still tools, resources, and the same wire protocol. If you haven't built a plain MCP server before, the build-mcp-server skill covers the base layer. This skill adds widgets on top.

Don't add UI for its own sake — most tools are fine returning text or JSON. Add a widget when one of these is true:

This is the opening of the README. Read the full README on GitHub.

Frequently asked about MCP App Builder

What else does fazxes publish alongside MCP App Builder?
MCP App Builder is one of 25 skills that DirSkills catalogs from fazxes/Claude-code, the repository it ships in. Its siblings there include Agent Development, Build An MCPB and Build MCP Server. Each one is a separate skill with its own page in this directory, installs the same way MCP App Builder does, and is maintained by fazxes in that same repository. The rest of the collection is listed on the fazxes/Claude-code page.
How does MCP App Builder compare to other AI Engineering skills?
MCP App Builder ranks #2454 by stars among the 2793 AI Engineering skills in this catalog. The most-starred ones next to it are Architecture Decision Records, AI-First Engineering and Agentic OS. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of MCP App Builder against them. Open each page to compare what they document and how they install.