---
title: Check
description: Inspect the environment. Missing tools are offered for install. Older tools are offered for update.
order: 1
---

# vibe21-system-check

Checks the environment. You do not configure the stack. You watch.

This skill is read-only. It does not install or upgrade. When something is missing or older than the pin, the agent offers a follow-up skill and waits for you to confirm.

## When to use it

Run this first on a new machine, a new agent profile, or any folder that has not been prepared for VIBE21.

Skip it only when a previous check on the same setup already passed and nothing has changed.

## How to run it

```
/vibe21-system-check
```

Use it in Claude Code or Cursor. The agent runs the bundled check and reports what it found.

## What it checks

Presence is enough. A different version than the pin is a warning, not a failure. The pin lives with the skill — this page does not freeze version numbers.

- **Homebrew** (macOS) — installs Git and the rest of the macOS toolchain. Apple's Xcode Git is older than VIBE21 expects.
- **winget** (Windows) — installs Git, fnm (for Node.js), and the rest of the Windows toolchain.
- **Node.js** — runtime for Next.js. The pin is Active LTS, never Current.
- **pnpm** — package manager every VIBE21 site uses: scaffold, install, and `pnpm dev`.
- **Git** — version control. Later skills push and pull. Memory records the short SHA.
- **GitHub CLI** (`gh`) — talks to GitHub from the terminal. Must be installed **and** logged in.

Linux skips Homebrew and winget.

`gh` not logged in is a fail even when the binary is present. The agent does not run `gh auth login` — that prompt is interactive, so you run it yourself.

## What happens

- The skill reports each tool as OK, missing, older than the pin, or newer than the pin.
- Missing tools: the agent offers [vibe21-system-install](/docs/vibe21-system-install) at the pinned versions. Nothing is installed until you confirm.
- Older than the pin: the agent offers [vibe21-system-update](/docs/vibe21-system-update). Newer than the pin stays as-is. The skill never downgrades.
- Later skills ([vibe21-web-new](/docs/vibe21-web-new), [vibe21-design-configuration](/docs/vibe21-design-configuration), [vibe21-web-preview](/docs/vibe21-web-preview)) can assume a usable environment.

When the check is done, create the site with [vibe21-web-new](/docs/vibe21-web-new).