Context

These conventions apply to all work on the Squad CLI tool (create-squad). Squad is a zero-dependency Node.js package that adds AI agent teams to any project. Understanding these patterns is essential before modifying any Squad source code.

Patterns

Zero Dependencies

Squad has zero runtime dependencies. Everything uses Node.js built-ins (fs, path, os, child_process). Do not add packages to dependencies in package.json. This is a hard constraint, not a preference.

Node.js Built-in Test Runner

Tests use node:test and node:assert/strict — no test frameworks. Run with npm test. Test files live in test/. The test command is node --test test/.

Error Handling — fatal() Pattern

All user-facing errors use the fatal(msg) function which prints a red ✗ prefix and exits with code 1. Never throw unhandled exceptions or print raw stack traces. The global uncaughtException handler calls fatal() as a safety net.

ANSI Color Constants

Colors are defined as constants at the top of index.js: GREEN, RED, DIM, BOLD, RESET. Use these constants — do not inline ANSI escape codes.

File Structure

• .squad/ — Team state (user-owned, never overwritten by upgrades)
• .squad/templates/ — Template files copied from templates/ (Squad-owned, overwritten on upgrade)
• .github/agents/squad.agent.md — Coordinator prompt (Squad-owned, overwritten on upgrade)
• templates/ — Source templates shipped with the npm package
• .squad/skills/ — Team skills in SKILL.md format (user-owned)
• .squad/decisions/inbox/ — Drop-box for parallel decision writes

Windows Compatibility

Always use path.join() for file paths — never hardcode / or \ separators. Squad must work on Windows, macOS, and Linux. All tests must pass on all platforms.

Init Idempotency

The init flow uses a skip-if-exists pattern: if a file or directory already exists, skip it and report "already exists." Never overwrite user state during init. The upgrade flow overwrites only Squad-owned files.

Copy Pattern

copyRecursive(src, target) handles both files and directories. It creates parent directories with { recursive: true } and uses fs.copyFileSync for files.

Examples

// Error handling
function fatal(msg) {
  console.error(`${RED}✗${RESET} ${msg}`);
  process.exit(1);
}

// File path construction (Windows-safe)
const agentDest = path.join(dest, '.github', 'agents', 'squad.agent.md');

// Skip-if-exists pattern
if (!fs.existsSync(ceremoniesDest)) {
  fs.copyFileSync(ceremoniesSrc, ceremoniesDest);
  console.log(`${GREEN}✓${RESET} .squad/ceremonies.md`);
} else {
  console.log(`${DIM}ceremonies.md already exists — skipping${RESET}`);
}

Anti-Patterns

• Adding npm dependencies — Squad is zero-dep. Use Node.js built-ins only.
• Hardcoded path separators — Never use / or \ directly. Always path.join().
• Overwriting user state on init — Init skips existing files. Only upgrade overwrites Squad-owned files.
• Raw stack traces — All errors go through fatal(). Users see clean messages, not stack traces.
• Inline ANSI codes — Use the color constants (GREEN, RED, DIM, BOLD, RESET).