Zygote

/create-zygote

Scaffolds a boilerplate project for a given stack in the current working directory.

Usage

/create-zygote sanic          # scaffold Sanic (Python async) backend
/create-zygote express        # scaffold Express (flat, no MVC layering) backend
/create-zygote express-mvc    # scaffold Express w/ routes -> controllers -> models layering
/create-zygote react-vite     # scaffold React + Vite (TypeScript) frontend
/create-zygote mern           # scaffold MERN: server/ (Express+mongoose) + client/ (React+Vite) side by side
/create-zygote fastapi        # scaffold FastAPI (Python async) backend
/create-zygote rails          # scaffold Ruby on Rails, full MVC (Note resource + SQLite)

Supported stacks (v1): sanic, express, express-mvc, react-vite, mern, fastapi, rails. More stacks (django, nextjs, vue, vanilla-html) planned — not yet implemented. If the requested stack isn't in this list, tell the user it's unsupported and list what's available. Do not attempt to scaffold an unlisted stack.

mern is a composite stack, scaffolded differently from every other stack — see "Scaffold steps for mern" under step 6 below. It reuses the express and react-vite templates as a base plus a small overlay (templates/mern/overlay/), instead of duplicating their files. It intentionally has no root package.json/orchestration — the two apps are run independently, in separate terminals.

Flow (follow in order, every invocation)

1. Parse stack name from the argument after /create-zygote.
2. Unsupported stack → stop, tell user supported list, do nothing else.
3. Detect OS from current session context (Darwin = macOS, or Linux, or Windows). Don't re-derive with extra commands if already known.
4. Dependency check for the requested stack (see table below). Run each check command via Bash.
5. If anything missing: show the user the exact list of missing tools + the exact install command(s) you intend to run for their OS, then ask for explicit confirmation before running any install command. Never install silently. This applies to system-wide/global tool installs (python, node, brew, homebrew itself, etc.) — not to project-local steps like pip install -r requirements.txt inside a venv, which are scoped to the new project dir and don't need a separate confirm beyond the overall scaffold going ahead.
6. Scaffold: copy the stack's template from templates/<stack>/ (relative to this skill's own directory) into the current working directory. Exception: mern — do not just copy templates/mern/; follow "Scaffold steps for mern" (below the Flow list, before the Dependency table) instead.
7. Local env setup (venv/npm install/etc, per stack — see table). These are project-scoped and reversible, run without extra confirmation.
8. Report: print what was created, the exact next command the user runs to start the app, and a Versions block listing the runtime + key package versions actually installed (see per-stack "Version check" command below — run it after local env setup, inside the venv/node_modules just created, and print its output verbatim).

Scaffold steps for mern (this is step 6, specifically for this stack — steps 1-5, 7, 8 above still apply as normal)

Run in order, every invocation of /create-zygote mern:

1. mkdir server client
2. Copy templates/express/. into server/ (base — flat Express, no MVC).
3. Copy templates/mern/overlay/server/. into server/, overwriting any same-named file (app.js, config.js, package.json, .env.example, README.md get replaced; db.js and models/User.js are added).
4. Delete server/models/index.js — it's the plain-express placeholder ("no ORM wired by default") and is now stale/wrong since models/User.js wires a real one.
5. Copy templates/react-vite/. into client/ (base, unchanged).
6. Copy templates/mern/overlay/client/. into client/, overwriting .env.example and README.md only.

Never overwrite an existing non-empty server/ or client/ without asking first (same rule as the general Notes section below).

Dependency table

sanic

Requires	Check cmd	macOS install	Windows install (PowerShell)
python3 (>=3.8)	python3 --version	brew install python3 (if brew missing, ask before installing Homebrew via its official install script first)	winget install Python.Python.3
pip	python3 -m pip --version	ships with python3 install above	ships with python install above
venv module	python3 -m venv --help	ships with python3	ships with python install above

fastapi

Requires	Check cmd	macOS install	Windows install (PowerShell)
python3 (>=3.8)	python3 --version	brew install python3 (if brew missing, ask before installing Homebrew via its official install script first)	winget install Python.Python.3
pip	python3 -m pip --version	ships with python3 install above	ships with python install above
venv module	python3 -m venv --help	ships with python3	ships with python install above

express / express-mvc

Requires	Check cmd	macOS install	Windows install (PowerShell)
node (>=18)	node --version	brew install node (if brew missing, ask before installing Homebrew via its official install script first)	winget install OpenJS.NodeJS.LTS
npm	npm --version	ships with node install above	ships with node install above

react-vite

Requires	Check cmd	macOS install	Windows install (PowerShell)
node (>=18)	node --version	brew install node (if brew missing, ask before installing Homebrew via its official install script first)	winget install OpenJS.NodeJS.LTS
npm	npm --version	ships with node install above	ships with node install above

mern

Requires	Check cmd	macOS install	Windows install (PowerShell)
node (>=18)	node --version	brew install node (if brew missing, ask before installing Homebrew via its official install script first)	winget install OpenJS.NodeJS.LTS
npm	npm --version	ships with node install above	ships with node install above

MongoDB itself is not checked or installed — server/db.js connects non-blocking, and the final report tells the user to point MONGO_URI at a running local Mongo or an Atlas connection string. Don't attempt to install/start a local MongoDB service.

rails

Requires	Check cmd	macOS install	Windows install (PowerShell)
ruby (>=3.2)	ruby --version	brew install ruby (if brew missing, ask before installing Homebrew via its official install script first)	winget install RubyInstallerTeam.RubyWithDevKit.3.4 (untested on Windows — verify ruby --version works after, RubyInstaller normally wires PATH itself)
rails gem	rails --version	gem install rails (after ruby install above)	gem install rails

Homebrew's Ruby is keg-only for gem binaries: after gem install rails, the rails command may not resolve on PATH yet. Before running any further ruby/rails/bundle command this session, run:

export PATH="$(ruby -e 'puts Gem.bindir'):$PATH"

Then re-check rails --version. Don't skip this — it's why rails --version can fail right after a successful install.

Local setup after scaffold (sanic)

• macOS/Linux:

  python3 -m venv venv
  source venv/bin/activate
  pip install -r requirements.txt
  cp .env.example .env
  

• Windows (PowerShell):

  python -m venv venv
  venv\Scripts\Activate.ps1
  pip install -r requirements.txt
  copy .env.example .env
  

• Final run command to report to user: python app.py (after activating venv).
• Version check (run after local env setup, venv still active, before final report):

  python3 --version
  pip show sanic | grep -i version
  pip show python-dotenv | grep -i version
  

  Print these under a "Versions" heading in the final report.

Local setup after scaffold (fastapi)

• macOS/Linux:

  python3 -m venv venv
  source venv/bin/activate
  pip install -r requirements.txt
  cp .env.example .env
  

• Windows (PowerShell):

  python -m venv venv
  venv\Scripts\Activate.ps1
  pip install -r requirements.txt
  copy .env.example .env
  

• Final run command to report to user: python app.py (after activating venv). Mention /docs for interactive API docs.
• Version check (run after local env setup, venv still active, before final report):

  python3 --version
  pip show fastapi | grep -i version
  pip show uvicorn | grep -i version
  

  Print these under a "Versions" heading in the final report.

Local setup after scaffold (express / express-mvc)

• macOS/Linux:

  npm install
  cp .env.example .env
  

• Windows (PowerShell):

  npm install
  copy .env.example .env
  

• Final run command to report to user: npm start.
• Version check (run after npm install, before final report):

  node --version
  npm --version
  npm list express --depth=0
  

  For express-mvc also run npm list ejs --depth=0. Print these under a "Versions" heading in the final report.

Local setup after scaffold (react-vite)

• macOS/Linux:

  npm install
  cp .env.example .env
  

• Windows (PowerShell):

  npm install
  copy .env.example .env
  

• Final run command to report to user: npm run dev.
• Version check (run after npm install, before final report):

  node --version
  npm --version
  npm list react --depth=0
  npm list vite --depth=0
  

  Print these under a "Versions" heading in the final report.

Local setup after scaffold (mern)

• macOS/Linux:

  cd server && npm install && cp .env.example .env && cd ..
  cd client && npm install && cp .env.example .env && cd ..
  

• Windows (PowerShell):

  cd server; npm install; copy .env.example .env; cd ..
  cd client; npm install; copy .env.example .env; cd ..
  

• Final run commands to report to user (two separate terminals, do not combine):

  cd server && npm start      # http://localhost:3000
  cd client && npm run dev    # http://localhost:5173
  

• Version check (run after both npm installs, before final report):

  node --version
  npm --version
  npm --prefix server list express --depth=0
  npm --prefix server list mongoose --depth=0
  npm --prefix client list react --depth=0
  npm --prefix client list vite --depth=0
  

  Print these under a "Versions" heading in the final report. Also remind the user Mongo isn't auto-installed — see server/README.md.

Local setup after scaffold (rails)

• macOS/Linux:

  bundle install
  bin/rails db:create db:migrate
  

• Windows (PowerShell):

  bundle install
  bin/rails db:create db:migrate
  

• Gems install into ./vendor/bundle (project-local, via the shipped .bundle/config) — not system-wide, no extra confirmation needed beyond the scaffold going ahead.
• Final run command to report to user: bin/rails server. Mention: / lists notes, /health returns JSON, /up is Rails' own built-in health check.
• Version check (run after bundle install, before final report):

  ruby --version
  rails --version
  bundle exec gem list sqlite3
  

  Print these under a "Versions" heading in the final report.

Notes

• Never overwrite an existing non-empty target directory without asking first.
• Templates live in templates/<stack>/ next to this file — copy their contents as-is (including dotfiles like .gitignore, .env.example) into the target dir.