Hallmark is an open-source design skill made by Together AI and published under the MIT license. It works in Claude Code, Codex, Cursor and OpenCode and aims to stop coding agents from producing pages with the tells that read as machine-made, such as an eyebrow label above every heading, tracked capitals, one colored word in a headline or a form that says thanks without sending anything. Version 2, a rebuild released in October 2026, reorganised the skill around themes, real material and redesigns.
A build starts with a pre-flight that reads the project and asks once for real material such as photos, screenshots and numbers; Hallmark does not invent them. It then offers three of its 48 themes that fit the prompt, or designs from scratch when you ask for a custom page, lays out the page from what the visitor came to do, and builds the hero alone before the rest. The sloplint script checks the result in a real browser at eight widths, and a subagent with fresh context reviews it. Gates are tiered: Floor checks such as contrast, focus states, reduced motion, invented facts and broken phone layouts always block a ship.
Hallmark can also redesign or audit an existing page with /hallmark redesign or /hallmark audit; a redesign keeps the content and wiring and fails if a link, field, handler or heading goes missing. It can capture screenshots from a URL, dev server or app, and uses a library of 755 openly licensed photographs from Wikimedia Commons, credited on each page, instead of stock sites.
Hallmark is free and needs no API key. Install it with npx skills add nutlope/hallmark (add -g for all projects) or as a Claude Code plugin; it needs Node 18 or later, and the browser checks additionally need Chrome and puppeteer-core.
