[SandroMaglione]

Requested by Sandro · project thread

Brings the loop ritmo-tools fx already runs on effects to sprites, tiles, and animation sheets. The patterns come from a study of agent skills that draw machines and animations (Anatomy, claude-animation, rossark-motion): plan before drawing, checks that name the pixels, look before the owner does, and read motion as numbers.

Tools (@typeonce/ritmo-tools)

• Shared craft checks. craft.ts moves from fx/core to pixel/core. pixel lint, check, fix, render, and sheet now warn on jaggies, doubles, and holes, each with its pixels. Doubles are read on the silhouette and on the outline's own color, and a box corner is no longer counted as a double (this applies to fx too).
• Animation checks. Sheets also get flicker on lone pixels only, so a limb moving between poses doesn't count, and the turn-around frames of a pingpong are skipped. They also get three motion checks: area (the body changing size), skate (the planted foot moving by uneven steps), and seam (the loop jumping back to its start). The report's motion gives the area per frame, the foot's steps, and ground.pixelsPerSecond, the speed the game must move the sprite at to keep the foot planted.
• pixel lint reads a written sprite sheet's .json.
• pixel look <files...> writes one PNG. The top row shows every piece at display size on the game's backdrop (a color, or a tile repeated), beside the stand-in player, all standing on one ground line. Below that, each frame is shown up close, with each warning's pixels ringed in magenta.
• New pixel.config.json fields. scale, backdrops, and standIn for look. accept takes warnings judged deliberate, per file, each with a reason. Errors cannot be accepted, and reports list accepted warnings under accepted.

Skill (@typeonce/ritmo)

• ritmo-pixel-art now works in Rounds: write a brief in the design notes before the first pixel, then check (fix, or accept with a reason), look, read motion as numbers, and act on the person's notes. It also gets a "what you see, and the usual fix" table.
• PIXEL-ART.md traces every new rule to its principle and its sources. It adds Rickett's "Walk Cycles" on slippage, and notes that the rounds are the skill's one procedure, asked for by the maintainer.

Samples (last commit, for review)

packages/tools/examples/pixel/ holds one round of the workflow:

• a brief;
• four code-drawn pieces: player, slime, chest and floor;
• an image generator's run cycle fixed with pixel sheet;
• look.png and look.report.json.

The fire spirit deliberately still fails the size check, since that was the round's finding. Drop or rework this commit after review.

Not in this PR

• fx banks keep their own backdrops and standIn. Moving them into pixel.config.json would change the bank format, so it is left for a follow-up.
• A review page with pinned comments for sprites, like fx's.

Checks

• pnpm run check passes.
• pnpm pack:check passes.
• pnpm --dir website build passes.
• New tests are in packages/tools/test/craft.test.ts.

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Generated by Claude Code

[SandroMaglione]

Performance regressions failed on one case: runtime query/iterate-write-10k took 0.264 ms against 0.199 ms on base (+32.8%).

This PR changes no runtime code. Its diff touches only packages/tools and the Markdown skill files under packages/core. The bench probably ran because packages/core changed. In the same run, the other critical cases moved the other way (frame/50-systems-5k −12%, checkpoint/rollback −7%), allocations are flat, and the type suite is unchanged. That pattern looks like runner noise on a single case.

I'll re-run the failed job once when the rest of the workflow finishes; GitHub refuses a re-run while the workflow is still running. If it fails a second time, I'll treat it as real.

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Generated by Claude Code