Hallmark — Anti-AI-Slop Design Skill for Claude Code, Cursor, and Codex
Hallmark — Anti-AI-Slop Design Skill
If you've ever asked an AI coding agent to build a landing page, you've seen the pattern: hero section → three feature cards → CTA → footer. Every time, same rhythm, same layout, just different colours.
Hallmark fixes this. Created by Nutlope (Hassan El Mghari) and powered by Together AI, Hallmark is a design skill for Claude Code, Cursor, and Codex that refuses to produce AI-generated-looking UIs. It encodes 57 slop-test gates, 20 distinct themes, and a pre-emit self-critique system that scores every output before it reaches your screen.
Why It's Trending
Hallmark hit 5,400+ GitHub stars in its first weeks because it solves a universal pain: every AI coding agent defaults to the same layout patterns. Hallmark forces structural variety — two pages for two different briefs shouldn't share the same hero → features → CTA → footer rhythm. They should feel like different websites, not colour-swaps of the same template.
The skill was built on the consensus of the anti-AI-slop design field: Anthropic's frontend-design skill, the Claude cookbook on frontend aesthetics, and the 2026 "tactile rebellion" movement. It's MIT-licensed and installs in seconds.
How It Works
Hallmark follows a 5-step pipeline that turns a plain-English design brief into a production-ready page or component.
Step 0 — Pre-Flight Scan
Before touching any code, Hallmark reads your project's DNA: font stack, colour palette, framework (Next.js, Astro, SvelteKit, vanilla), motion libraries, and spacing scale. It caches these findings in .hallmark/preflight.json so subsequent runs don't re-scan.
If a design.md file exists at the project root, Hallmark treats it as a locked design system and defers to it for all token values — typography, colour, spacing, and motion.
Step 1 — Genre and Signal Detection
Hallmark classifies the brief into one of four genres: Editorial, Modern-Minimal, Atmospheric, or Playful. It also detects creative-intent signals — if the user names a brand colour or asks for something the 20 catalog themes can't carry, it dispatches to a Custom branch that constructs a one-off OKLCH palette with a free-font pairing.
Step 2 — Theme and Macrostructure
Catalog mode (default) picks from 20 named themes — Hum, Cobalt, Carnival, Lumen, Garden, Riso, and more. Each theme defines a colour anchor, type-pairing, and spacing ethos.
Custom mode fires only when the brief carries creative intent that no catalog theme fits. It builds a made-to-measure palette, type, and layout from scratch.
Hallmark then selects a macrostructure — the whole-page shape — from catalogue of patterns. This is the key differentiator: two briefs of the same type get different structural fingerprints (section-heading placement, body composition, divider language, button voice, image treatment, and reveal pattern).
Step 3 — Design Generation
The design is rendered with locked tokens (no inline OKLCH/hex values), honest copy (no invented metrics like "+47% conversion"), and six disciplines that apply to every verb: pre-emit self-critique, no re-drawn chrome, mobile responsiveness at 320/375/414/768px, and no italic headers (a reliable AI tell).
Step 4 — Slop-Test Gates (57 Checks)
Before any output is delivered, it passes through 57 slop-test gates. These catch:
- Anti-patterns: fake testimonials, invented numbers, stock-photo clichés
- Token discipline: every colour and font must reference a named
var(--token) - Mobile safety: no horizontal scroll, no two-line clickable text, collapsible section heads
- Typography purity: no italic headers, no re-drawn browser chrome
Component-Scope Flow
If the brief targets a single element (button, card, modal, input), Hallmark switches to Component scope. It skips macrostructures and hero patterns, and instead produces the component plus an 8-state demo wrapper showing default, hover, focus, active, disabled, loading, error, and success states — all rendered in a single preview file.
Installation
Install Hallmark in seconds using npx:
npx skills add nutlope/hallmark
Run this command any time to update. Or copy the SKILL.md and references/ directory into:
- Claude Code:
~/.claude/skills/hallmark/ - Cursor:
.cursor/rules/hallmark.mdc - Codex:
~/.codex/skills/hallmark/
Usage
Hallmark has one default behaviour and three explicit verbs:
| Verb | What it does |
|---|---|
| (default) | Build new UI. Picks macrostructure, applies rules and slop test. |
hallmark audit <target> |
Score existing code against anti-patterns. Punch list, no edits. |
hallmark redesign <target> |
Keep copy + IA + brand, rebuild visual structure with a different fingerprint. |
hallmark study <screenshot | URL> |
Extract the design DNA: macrostructure, type-pairing, colour anchor. |
Examples
# Build a landing page (default)
"Build a landing page for a sourdough starter kit"
# Audit an existing page
hallmark audit ./index.html
# Redesign with a specific mood
hallmark redesign ./src/pages/ --mood atmospheric
# Study a design from a URL
hallmark study https://example.com