Skill v1.0.0

version: "1.0.0" name: "windows-compatibility" description: "Cross-platform path handling and command patterns" domain: "platform" confidence: "high" source: "earned (multiple Windows-specific bugs: colons in filenames, git -C failures, path separators)"

Context

Squad runs on Windows, macOS, and Linux. Several bugs have been traced to platform-specific assumptions: ISO timestamps with colons (illegal on Windows), git -C with Windows paths (unreliable), forward-slash paths in Node.js on Windows.

Patterns

Filenames & Timestamps

• Never use colons in filenames: ISO 8601 format 2026-03-15T05:30:00Z is illegal on Windows
• Use `safeTimestamp()` utility: Replaces colons with hyphens → 2026-03-15T05-30-00Z
• Centralize formatting: Don't inline .toISOString().replace(/:/g, '-') — use the utility

Git Commands

• Never use `git -C {path}`: Unreliable with Windows paths (backslashes, spaces, drive letters)
• Always `cd` first: Change directory, then run git commands
• Check for changes before commit: git diff --cached --quiet (exit 0 = no changes)

Commit Messages

• Never embed newlines in `-m` flag: Backtick-n (\n) fails silently in PowerShell
• Use temp file + `-F` flag: Write message to file, commit with git commit -F $msgFile

Paths

• Never assume CWD is repo root: Always use TEAM ROOT from spawn prompt or run git rev-parse --show-toplevel
• Use path.join() or path.resolve(): Don't manually concatenate with / or \

Path Comparison (Case Sensitivity)

• Never use case-sensitive `startsWith` or `===` for path comparison on Windows or macOS: These filesystems are case-insensitive — C:\Users\ and c:\users\ refer to the same location
• Use platform-aware comparison: Check process.platform === 'win32' || process.platform === 'darwin' and lowercase both sides before comparing
• Pattern:

```typescript const CASE_INSENSITIVE = process.platform === 'win32' || process.platform === 'darwin';

function pathStartsWith(fullPath: string, prefix: string): boolean { if (CASE_INSENSITIVE) { return fullPath.toLowerCase().startsWith(prefix.toLowerCase()); } return fullPath.startsWith(prefix); } ```

• Where it matters: Security checks (path traversal prevention), rootDir confinement, any path-contains-path validation
• Linux is case-sensitive: Do NOT lowercase on Linux — /Home/ and /home/ are different directories

Examples

✓ Correct:

// Timestamp utility
const safeTimestamp = () => new Date().toISOString().replace(/:/g, '-').split('.')[0] + 'Z';
// Git workflow (PowerShell)
cd $teamRoot
git add .squad/
if ($LASTEXITCODE -eq 0) {
  $msg = @"
docs(ai-team): session log
Changes:
- Added decisions
"@
  $msgFile = [System.IO.Path]::GetTempFileName()
  Set-Content -Path $msgFile -Value $msg -Encoding utf8
  git commit -F $msgFile
  Remove-Item $msgFile
}

✗ Incorrect:

// Colon in filename
const logPath = `.squad/log/${new Date().toISOString()}.md`; // ILLEGAL on Windows
// git -C with Windows path
exec('git -C C:\\src\\squad add .squad/'); // UNRELIABLE
// Inline newlines in commit message
exec('git commit -m "First line\nSecond line"'); // FAILS silently in PowerShell

Anti-Patterns

• Testing only on one platform (bugs ship to other platforms)
• Assuming Unix-style paths work everywhere
• Using git -C because it "looks cleaner" (it doesn't work)
• Skipping git diff --cached --quiet check (creates empty commits)
• Wrong — case-sensitive path check on Windows and macOS:

``typescript if (!resolved.startsWith(rootDir + path.sep)) { throw new Error('Path traversal blocked'); } // Fails: 'c:\\Users\\temp\\file'.startsWith('C:\\Users\\temp\\') → false ``