Set Up Claude Code

Claude Code is an agentic coding assistant distributed as a global npm package requiring Node.js 18+. Verify that Node.js and npm are installed in your shell. (Missing Node? Windows: winget install OpenJS.NodeJS.LTS · macOS: brew install node · Linux: sudo apt install -y nodejs npm)

Claude Code requires Git to track changes, render diffs, and inspect project branches. On Windows, also verify that PowerShell execution policy allows npm wrapper scripts.

Install the official Claude Code CLI using either the native installer script or global npm package. Native installer sets up .local/bin/claude (Windows: irm https://claude.ai/install.ps1 | iex · macOS/Linux: curl -fsSL https://claude.ai/install.sh | bash). Alternatively, install via global npm: npm install -g @anthropic-ai/claude-code.

Confirm that the claude binary is accessible from your current terminal and prints a valid version number.

Authenticate your Claude Code session. Running claude or claude login opens your browser to Anthropic's OAuth portal to authorize your terminal workstation.

For headless Linux build machines or Docker containers, configure a direct API key from the Anthropic Console. (Optional for desktop workstation users: if you completed Step S05 browser login, proceed directly to S07.)

Run claude doctor to verify that runtime versions, API network connectivity, disk permissions, and authentication tokens are healthy.

Create a CLAUDE.md file in your repository root. Claude Code reads this file at the start of every session to enforce coding conventions, test commands, and architectural boundaries.

Inspect configuration settings governing command confirmations, automatic approvals, and sandbox security rules.

Execute single-shot prompt requests using claude -p "prompt" for automated shell scripting and CI/CD pipelines.

Pipe git diffs, build logs, or file contents directly into Claude via STDIN for fast automated code analysis.

Create a disposable test directory, generate a simple script, verify the test execution, and cleanly delete the sandbox.

Explore essential slash commands including /help, /compact, /init, and /cost.

Monitor your active session token spend and estimated dollar cost using the /cost slash command.

Bookmark high-velocity commands for your everyday developer workflow.

Enforce Fleet Rule #31: Apply path resolution guards, off-volume profile backups, and non-destructive restore drills.

1. Six-Line Onboarding Checklist

$check = Join-Path $env:TEMP "bbb-onboarding-checklist.txt"; @("agent:","rules file:","memory location:","permissions:","delete guard:","backup path:","final check:") | Set-Content -Encoding ascii $check; Get-Content $check; Write-Host "Fill every line for this agent. Rerun this checklist for the next agent."

2. Variable-Limit Guard Demo

$tmp = $env:USERPROFILE; $literal = $env:USERPROFILE; foreach ($src in @('$tmp','$env:GROK_HOME','python cleanup.py')) { if ($src -like "*$literal*") { "HIT $src" } else { "MISS $src" } }; if ([IO.Path]::GetFullPath($tmp) -eq [IO.Path]::GetFullPath($env:USERPROFILE)) { "REFUSE resolved tmp: it is the user profile. Text guards miss dollar-variables and python cleanup.py. 2026-09-23 Remove-Item of user profile is the example." }

3. Off-Volume Profile Backups

$dest = "D:\Backups\llm-profiles\$(Get-Date -Format yyyyMMdd-HHmm)"
New-Item -ItemType Directory -Force -Path $dest | Out-Null
foreach ($d in @(".agy", ".claude", ".codex", ".grok", ".grokbot")) {
  if (Test-Path "$env:USERPROFILE\$d") {
    robocopy "$env:USERPROFILE\$d" "$dest\$d" /E /NFL /NDL /NJH /NJS
    Write-Host "Backed up $dest\$d"
  }
}
Get-ChildItem $dest

4. Practised Restore Drill

$drill = Join-Path $env:TEMP "bbb-restore-drill"; $src = Join-Path $drill "source"; $bak = Join-Path $drill "backup"; $back = Join-Path $drill "restored"; New-Item -ItemType Directory -Force -Path $src,$bak,$back | Out-Null; Set-Content -Encoding ascii -Path (Join-Path $src "proof.txt") -Value "bbb-restore-proof"; Copy-Item (Join-Path $src "proof.txt") (Join-Path $bak "proof.txt"); Remove-Item (Join-Path $src "proof.txt"); Copy-Item (Join-Path $bak "proof.txt") (Join-Path $back "proof.txt"); Get-Content (Join-Path $back "proof.txt"); Write-Host "Practised restore wrote proof into $back. Do not delete your user profile to test this."

node -v; npm -v