Hassan El Mghari · @Nutlope ↗ Hallmark
Hallmark is a design skill for Claude Code, Codex, Cursor and OpenCode by Together AI that builds websites and pages that look designed, with 50 themes and browser-based checks.
The roster
What it does
Hallmark is an open-source design skill from Together AI for Claude Code, Codex CLI, Cursor and OpenCode. It builds new websites and pages that refuse to look AI-generated, holding a hard floor of rules and then leaving the design to the agent.
The repo ships one skill with 50 themes, each a material of paper, type, colour, surfaces and texture with a picture of a finished page, plus 21 page shapes and a library of 755 openly licensed photographs. Ask for custom and it drops the themes and designs from your prompt alone under the same checks. It can also redesign or audit an existing page when you name it.
What sets it apart is verification: sloplint renders each page in a real browser at eight widths, flags tells like eyebrows, tracked-capital labels and invented facts, and a fresh-context reviewer has the last word before the page ships.
When to use it
- You want agent-built sites that do not look generated
Install Hallmark once and every new page your agent builds starts from a dealt theme and passes the same floor of design rules.
- You need to check a page for AI design tells
Run its sloplint script on any HTML file or folder to get a list of failures and reflex defaults, rendered and screenshotted in a real browser.
- You are redesigning a page without breaking it
Its redesign mode records every link, field and handler first and fails the rebuild if any of them went missing.
Common questions
How do I install Hallmark?
Run npx skills add nutlope/hallmark -g to install it for every project, or leave off -g for the current one. It also installs as a Claude Code plugin from the nutlope/hallmark marketplace.
Which agents does Hallmark work with?
Claude Code, Codex CLI, Cursor and OpenCode. You invoke it with /hallmark or $hallmark in Codex, or simply describe a new build and it fires on its own.
Is Hallmark free?
Yes. Hallmark is MIT licensed. The photo library lists Wikimedia Commons images that keep their own open licences, and Hallmark credits each one it uses on the page.
What does it need to run?
Node 18 or later. The browser checks and screenshots also need puppeteer-core and Chrome; without them the static checks still run. A Together AI key is optional.