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Hallmark Claude skill

A design skill from Together AI that deals a theme from 50 options, builds pages around the visitor's goal and lints the result in a real browser for AI-looking tells.

Nutlope/hallmark 1 skill Design & frontend
Our verdict Recommended

A substantial, well-tested design skill with a real linter and no hidden behavior; the opinionated rules are the main thing to check against your taste.

5/5 Depth expertise shipped Note Security Review before installing 1d Maintenance Updated today 77K Adoption installs OK License MIT, commercial OK

What Hallmark does

Hallmark is a single, large design skill for building new websites and pages. Instead of letting the model fall into its usual defaults, it enforces a hard "Floor" of rules: every colour and font goes through a declared token, no animating layout properties, no eyebrow labels or tracked capitals, no invented metrics or testimonials, a hero whose headline and action fit on a 1280 x 800 screen, and a usable phone layout. Softer "Reflex" and "Finish" tiers can be overruled with a stated reason or never block a ship.

On each build it deals three themes from a catalog of fifty (each is a short reference file describing paper, type, colour and components, with a screenshot) and lays the page out around the job: a booking page books, a shop sells. You can ask for a custom design, point it at a URL or dev server so it captures your real product, or run /hallmark redesign <path> and /hallmark audit <path> on existing files. A bundled linter, sloplint, checks the output statically and, with puppeteer-core and Chrome, in a rendered browser; a fresh-context reviewer gets the last word. The repo ships about 150 reference files, ten scripts, tests and fixtures, a photo list that points at openly licensed Wikimedia Commons images, and an optional edit-time hook for Claude Code.

Good for

  • Building landing pages and marketing sites that should not look model-generated
  • Auditing or redesigning an existing HTML/CSS page against a fixed rule set
  • Teams that want a repeatable design floor enforced by a linter

Not for

  • Editing a page inside an established design system you must keep
  • Backend or non-visual work
  • Quick throwaway mockups where a long checklist slows you down

What's inside depth 5/5

One 18 KB SKILL.md backed by about 150 reference files (50 themes), 10 scripts including a large linter, 17 test files and fixtures, CI and a plugin manifest.

Skills
1
Reference docs
151
Scripts
10
Tests / evals
31
Templates
0
Avg SKILL.md
17.8 KB

Counted from the repository file tree. How we score depth.

Dependencies and costs

  • Node 18 or later
  • puppeteer-core and Chrome or Chromium for the render checks (optional; static checks run without them)
  • TOGETHER_API_KEY only if you opt in to image generation via scripts/imagegen.mjs
  • Telemetry: none found. The only outbound calls are font links in generated pages (Google Fonts, Fontshare), Wikimedia Commons photo URLs, and the opt-in Together AI image endpoint used when you set TOGETHER_API_KEY.

Security review

Review before installing

A web-design skill with a local linter, theme tools and screenshot helpers, all run through Node. Image generation is opt-in via your own TOGETHER_API_KEY and sends prompts to Together AI. An optional installer can add a PostToolUse lint hook to a Claude Code settings file when you run it. Part of the repo was not available to us.

Worth knowing

  • Makes network requestsOpt-in image generation posts your prompt to api.together.xyz; theme.mjs photos --save downloads images from upload.wikimedia.org; generated pages link Google Fonts and Fontshare.skills/hallmark/scripts/imagegen.mjs:63
  • Needs an API key for its own serviceTOGETHER_API_KEY is read from the environment and sent only to Together AI; generation is skipped when the key is not set.skills/hallmark/scripts/imagegen.mjs:52
  • Changes files outside your projectWhen run, install-hook.mjs adds a PostToolUse lint hook to .claude/settings.json (project, or ~/.claude with --global; --print and --remove supported), and install.mjs copies the skill into ~/.claude/skills, ~/.agents/skills and ~/.config/opencode/skills; both are explicit commands and flow.md only offers the hook.skills/hallmark/scripts/install-hook.mjs:52
  • Relies on a CLI or package we could not reviewRender checks and screenshots need puppeteer-core (or puppeteer) and an installed Chrome/Chromium; --cdp can attach to an app you started with a DevTools port.skills/hallmark/scripts/capture.mjs:88

What we checked

The repository (844 files) on Oct 29, 2026. Not a full review: 351 of 844 files were not downloaded (large repository; we reviewed the skill folders); it relies on code outside the repository: npm package puppeteer-core (suggested via `npm i -g puppeteer-core`) and the installed Chrome/Chromium; 351 readable files in the repo were not available to us (including .claude-plugin manifests, workflows, eval/ scripts and some references); sloplint.mjs (230 KB) and theme.mjs (59 KB) were not read line by line.

NVIDIA SkillSpector static scan: 18 pattern hits (Data Exfiltration 11, System Prompt Leakage 3, MCP Rug Pull 2, Server-Side Request Forgery 1, Agent Snooping 1). The 169.254.169.254 hit is a URL-safety rule telling the agent to refuse private and metadata addresses; '~/.codex/config.toml' is a doc line telling the agent never to edit it; 'return rules' hits are ordinary lines in sloplint.mjs; the external-transmission hits are the Fontshare font CDN and the opt-in Together AI endpoint.

A review, not a certification. Skills change after we check them — read the files before installing.

License

MIT — commercial use allowed. Photos referenced from Wikimedia Commons keep their own licences (CC0, public domain, CC BY, CC BY-SA) and must be credited.

Can it run unattended?

Not really. It is built for an interactive design session with a themed build, a lint pass and a reviewer handoff, not for long unattended loops.

Alternatives to Hallmark

Impeccable

pbakaus/impeccable

A design skill with 24 commands (polish, bolder, critique, audit, harden and more), a 62-rule deterministic slop detector and an optional edit hook.

With caveats Broad access Depth 4/5

Taste Skill

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An anti-generic-design skill that gives the agent an art direction, open-licensed photos and a headless-browser check loop for web pages and app screens.

Recommended Check first Depth 4/5

UI UX Pro Max

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A design skill backed by searchable style, palette and font catalogs, with a design-system generator and five companion design skills.

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emilkowalski/skills

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Recommended Check first Depth 3/5

FAQ

What is Hallmark?

Hallmark is a design skill by Together AI for Claude Code, Codex, Cursor and OpenCode. It builds new pages from a catalog of 50 themes under a fixed set of rules and lints the result for the visual tells that make a page look AI-generated.

How do I install Hallmark?

Run npx skills add nutlope/hallmark -g, or leave off -g to install into the current project. For Claude Code you can also use /plugin marketplace add nutlope/hallmark and then /plugin install hallmark@hallmark. It needs Node 18 or later, and the browser-based checks also need puppeteer-core and Chrome.

Is Hallmark safe to install?

We found no hidden network calls or credential reads. The scanner's high-severity hits are documentation text and ordinary code lines, and image generation only runs if you set your own TOGETHER_API_KEY. The edit-time hook is a separate script you run on purpose.

Hallmark vs Impeccable: which should I use?

Both are design skills for coding agents. Hallmark deals a theme and enforces a hard floor with its own linter, while Impeccable is a design vocabulary of commands such as polish, bolder, critique and audit that you steer with. Hallmark is stronger for building new pages; Impeccable suits iterating on an existing design.

Sources: GitHub repository (stars, license, file tree, last push Oct 28, 2026); install counts from skills.sh via Best Skills (CC BY 4.0). Review based on the README and SKILL.md files as published.