Studio setup

Stack. Claude Code (desktop Code tab), Node 22+, Playwright's pinned Chromium, ffmpeg with libx264, and Python in a .venv with numpy, scipy, librosa and soundfile.

Rules vs enforcement. CLAUDE.md holds the house rules (render contract, look, sound, review loop). Anthropic's docs describe CLAUDE.md as context, not enforced configuration, so .claude/hooks/check-determinism.mjs runs after every Write/Edit. It flags banned calls, and exit code 2 sends the violation back to Claude. In testing, Claude wrote Math.random(), the hook flagged it, and Claude rewrote it with the seeded RNG on its own. Lines marked // preview-only are exempt.

Fact-check of the article

• ❌ "Claude Code can listen to the render." Opus has no audio input. Sync is checked numerically.
• ❌ pip install librosa fails on Homebrew Python (externally managed). Use a venv.
• ✅ Opus 5.5 defaults to medium effort. Use xhigh for new films and medium for small fixes. Run your own comparisons; don't treat these as rules.
• ⚠️ "Only Claude Code can render." Chat sandboxes can run code too, but network allowlists blocked the Chromium download. Local is the practical choice.

Encoding rules and why

• Even width and height, because yuv420p stores color at half resolution.
• CRF 16 for high quality, and +faststart so web players start immediately.
• About −14 LUFS integrated and a true peak of −1 dBTP or lower, measured on the final file.

A real-world snag. There were two Claude Code installs (an old Homebrew cask and the new native one), and the old one was first on PATH. Fix: put ~/.local/bin on PATH and uninstall the cask.