# Review by Principal Systems Engineer (Google/Stripe caliber) (Round 4)

## Review Complete — Principal Systems Engineer

**VERDICT: approve**

**FINDINGS:**
- `[scripts/generate-homebrew-formula.sh]`: `setuptools<78` pin is a contained maintenance tripwire — CI will fail loudly when it needs updating. Non-blocking.
- `[deploy/provision.sh]`: `NODE_MAJOR=20` hardcoded — one-line change when Node 22 LTS is adopted. Non-blocking.
- `[scripts/generate-homebrew-formula.sh]`: GNU sed regex for blank-line trimming is opaque but has a fallback and only runs on Ubuntu CI. Non-blocking.
- `[.github/workflows/release.yml]`: Concurrency control, failure alerting, and credential handling are all correct — production-ready.

**SYNTHESIS:**
This is a clean, well-structured infrastructure PR that I'd be comfortable paging on. The failure modes are well-contained: if formula generation breaks, CI alerts via a GitHub issue and existing installs are unaffected. If the tap push fails due to a race, `git pull --rebase` handles it. If provisioning fails on a VM, the step-numbered output tells you exactly where. The credential handling follows best practices (credential helper for git auth, silent input for API keys, `chmod 600` env files with a systemd-creds recommendation). The `detect_install_method()` heuristic is simple and correct — three string checks with a safe fallback. 403 tests pass with zero failures. Every PRD requirement maps to a concrete implementation. The blast radius of any single failure is limited to the subsystem that failed — no cascading breakage. Ship it.

Review saved to `cOS_reviews/reviews/principal_systems_engineer/20260330_182656_round2_add_brew_installation_we_should_be_able_to_have.md`.
