Prefab Dev Build

Organization

PrefectHQ

prefab-dev-build

How to build and preview renderer/playground changes locally. Use this skill when modifying the renderer (themes, components, styles), the playground (theme picker, examples), or any Python source that needs to appear in the playground. Covers the build pipeline, common pitfalls, and how to iterate.

Overview

Publisher	PrefectHQ
Repository	`prefab`
Skill name	`prefab-dev-build`
Stars	693
Forks	70
Bundled files	Instructions only
License	Apache-2.0
Links	Skill source Repository Homepage

Markdown instructions
A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.
Works with any LLM
AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.
Self-contained
Everything the model needs lives in the instructions — no extra files to sync.
Open source
Published by PrefectHQ on GitHub. Read the source before you install it.

Installation

Install the Prefab Dev Build AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

Open the app and go to Plugins → Skills.
Choose "Install from GitHub".
Paste the skill folder URL below and confirm.
Enable the skill in any chat where you want it available.

Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills

git clone --depth 1 https://github.com/PrefectHQ/prefab.git /tmp/prefab
mkdir -p .claude/skills
cp -r /tmp/prefab/skills/prefab-dev-build .claude/skills/prefab-dev-build

Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable Prefab Dev Build in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads Prefab Dev Build on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so Prefab Dev Build is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

Loaded only when it is needed
The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.
Switch models mid-chat
Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

Building and Previewing Renderer/Playground Changes

The One Command

After changing renderer source, Python source, or playground code:

bash
uv run prefab dev build-docs

This is the only command you should use. It orchestrates the full pipeline with smart caching (only rebuilds what changed). Never run raw npm build commands (npm run build:playground, npm run build:renderer) directly — they skip critical steps.

What the Pipeline Does

Renderer build (if TS source changed) — npm run build:renderer builds the code-split ESM bundle for CDN delivery (the primary renderer artifact)
Python bundle generation — serializes all src/prefab_ui/**/*.py into renderer/src/playground/bundle.json for Pyodide
Playground build (if playground source changed) — runs Vite with VITE_LOCAL_PLAYGROUND=1 so the Python bundle is inlined
Copy to docs/ — puts built files where prefab playground and mintlify dev expect them

Note: build-docs builds the CDN renderer. The bundled single-file renderer (airgapped fallback) is built separately via prefab dev build-renderers.

Previewing

bash
# Start the playground (serves from docs/)
uv run prefab playground

# Or start the full docs site
mintlify dev --dir docs

The playground runs on port 5174 by default.

Common Mistakes

"attempted to install wheel before downloading it" — the playground was built without VITE_LOCAL_PLAYGROUND=1. This happens when you run npm run build:playground directly instead of prefab dev build-docs. Fix: run the full pipeline.

Playground shows stale Python code — bundle.json is stale. The full pipeline regenerates it; raw npm commands don't.

Renderer changes not visible in deploy previews — deploy previews load chunks from the CDN (@latest), not from the branch. Test renderer changes locally.

Reference

Full build and release details: dev-docs/build-pipeline.md

Frequently asked questions

What does the Prefab Dev Build AI skill do?

Why use Prefab Dev Build on TypingMind?

Because you install it once and use it with any model. Prefab Dev Build is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Prefab Dev Build in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/PrefectHQ/prefab/tree/main/skills/prefab-dev-build. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Prefab Dev Build?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Prefab Dev Build?

As many as you like. As long as a model supports skills, you can use Prefab Dev Build with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Prefab Dev Build AI skill free?

Yes. It is published on GitHub by PrefectHQ under the Apache-2.0 license. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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Overview

Installation

Install in TypingMind

Install in another agent

Use it in TypingMind

Works with any AI model

Skill instructions

Building and Previewing Renderer/Playground Changes

The One Command

What the Pipeline Does

Previewing

Common Mistakes

Reference

Frequently asked questions

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