Hallmark

Hallmark is an open-source design skill for Claude Code, Cursor, and Codex — made by Together AI — that plugs into coding agents to eliminate the visual slop those tools produce by default. Instead of a template, it picks a macrostructure for the brief, dresses it in one of twenty themes, runs fifty-seven slop-test gates plus a pre-emit self-critique, and refuses the on-distribution defaults every LLM was trained into. Two pages generated for two different briefs come out feeling like different sites, not colour-swaps of the same shadcn dashboard.

The skill exposes four verbs. The default verb builds new UI: it picks the structure, applies the rule-set, and runs the slop test before handing back. hallmark audit <target> scores existing code against the anti-patterns and returns a punch list without edits. hallmark redesign <target> throws out the structure but keeps copy, information architecture, and brand — then rebuilds with a different fingerprint. hallmark study <screenshot | URL> extracts the design DNA of a page you admire (macrostructure, type-pairing, colour anchor) and can emit a portable design.md handoff for other AI tools. It refuses pixel-clones and paid templates.

Installation is a git clone into the agent's skills directory — Claude Code discovers it automatically; Cursor and Codex reference it in a rules file. A live demo at usehallmark.com cycles through the twenty themes on press-T. Because Hallmark is a specification rather than a runtime, it works across model providers and stays effective as models get better. It has become one of the most-shared design skills in the coding-agent community — a good example of how the Skill format lets designers ship taste as reusable, model-agnostic packages.