Verify: before, after, and nothing changed

Loaded by steps 1 and 7. The browser is one your agent can script, one session at a time; a hidden pane or background tab gets no animation frames, so go headless when the pane is hidden (the perf-pass skill’s ../../perf-pass/references/survey.md, Driving the app). Mute the app’s audio once it loads. One fixed viewport for every shot (1200 × 800).

Before

• Shots: the game at each play position (reached the same scripted way every time, animation frozen or at a fixed moment if the app allows), and every studio area’s play view (&t=0&clean=1). Save with the old page’s own capture, or a browser screenshot of the canvas when it has none; the after shots are taken the same way.
• Numbers: ledger() at each play position (draws and triangles, every pass), from the console helpers the app has today.
• Bundle: the production build’s first load: the entry and every chunk index.html preloads (<link rel="modulepreload">), each with its bytes and gzipped bytes, and which of them already hold a dev tool (a catch-all vendor chunk group often does). The report’s before/after compares these.
• Checks: typecheck, lint, tests, build, run the project’s way. Note any that already fail.

After

• Checks: the same, all green (or failing exactly as before, said so).
• Without the flag, on the production build (vite preview or the project’s equivalent): load the game, read the network requests: no chunk holding three-meter, three-audit or a panel is fetched. In the built files, neither the entry nor any chunk index.html preloads holds the tools’ code: search them for three-meter’s PerformanceMonitor and three-audit’s findZFighting. Not for perf-hud (the app’s own HUD storage key holds it) nor a bare installAuditHelpers (only the name the drop-in calls). Total the preloaded bytes again.
• With ?debug: the HUD shows, docked where the copy had it, with the budgets file’s lines (calls and triangles amber past frame) and the quality line (dpr 1.5 · steady); tris() and ledger() answer in the console; each panel the app asked for opens. In dev without the flag, the console helpers answer and no HUD shows.
• Studio: every area and view the old page had opens, the readout fills, summary() answers, saveShot writes through three-studio serve.
• Play-view diff: the after shots at the same positions and views, then three-studio diff before.png after.png --max 0.1 --out mask.png for each pair and a three-studio montage of all pairs. The game’s shots at a pinned quality rung equal to the old ratio, so the swap to adaptive quality doesn’t show as a difference.
• Numbers: ledger() at each play position again; draws and triangles match the baseline (a pass that moves no geometry moves no numbers).

Done when the checks are green, the bundle and network checks hold, and every diff is about 0.1% of pixels or under with nothing in its mask.