Hallmark enforces design standards for Claude Code, Cursor and Codex to catch machine-made tells—tracked capitals, empty frames, misaligned heroes—before they ship.

AI coding assistants generate UI with visible patterns that read as machine-made. Hallmark, a design skill for Claude Code, Cursor, Codex and OpenCode, catches those tells in a real browser before the page ships.

What it catches

The tool enforces a hard floor against specific machine-generated patterns: eyebrows above every heading, tracked-capital labels, one coloured word in a headline, pages of empty frames or nothing but photographs, heroes that miss their screen, email sign-ups at the end of every page, and forms that say thanks without sending anything. Once the floor passes, a fresh-context reviewer gets the last word.

How it works

Hallmark reads your project and deals three themes from a catalog of fifty material-based options. It builds the page around what the visitor came to do, then lints the result in a real browser against those machine-made tells. Each theme is a material—paper, type, colour, surfaces, components and texture—not a plan. Two prompts in one theme produce two different pages.

The build runs in stages: pre-flight reads your fonts, palette and framework; the hero is rendered and reviewed cold before the rest of the page exists; then sloplint.mjs --render checks the page at eight widths and a subagent reviews it with fresh eyes.

What you can do with it

Start a new page by describing it in Claude Code, Cursor or Codex. Redesign an existing page with /hallmark redesign ./src/app, which keeps content and wiring but changes the system and layout. Audit a page with /hallmark audit ./index.html to only report tells without rebuilding. Custom themes are available on request.

The tool includes 755 openly licensed photographs picked per subject and credited on the page. Each finished page is self-contained HTML and CSS, stamped in its first CSS comment with the decisions it took.

Install and limits

Install with npx skills add nutlope/hallmark -g (Node 18 or later). The -g flag installs for every project; leave it off to install into the current one. Browser checks and screenshots require Chrome and npm i -g puppeteer-core; without them, static checks still run. The tool is MIT licensed and made by Together AI.

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