Taste can't be linted. The tells can.

Description and use

Hallmark lint identified 16 design violations, including 6 eyebrow issues and 2 purple‑to‑blue gradients, enabling precise, repeatable fixes that are hard to achieve with subjective design prompts.

Problem

Design decisions that rely on subjective taste are hard to test automatically, leading to inconsistent or sub‑optimal UI outcomes.

Outcome

Hallmark detected 16 violations, including 6 eyebrow issues and 2 purple‑to‑blue gradients, and confirmed that other rules (letter‑spacing, middle‑dot strings, focus styles) passed. The audit enabled precise, repeatable fixes that would be hard to achieve with subjective design prompts.

Workflow

• Install Hallmark with npx skills add nutlope/hallmark -g
• Run the audit: hallmark audit ./index.html or node skills/hallmark/scripts/sloplint.mjs index.html
• Review the lint output and address each failing rule
• Re‑run the audit to confirm all issues are resolved

Evidence

Hallmark is an MIT‑licensed skill for Claude Code, Codex, Cursor and OpenCode, made by Hassan El Mghari (Nutlope) at Together AI.

Source

Install is one line: npx skills add nutlope/hallmark -g

Source

I read the functions, ported five checks to about 100 lines of Python, and ran them on the HTML and CSS of somiibo.com… The CSS is one 217 KB bundle: Bootstrap 5.3.6, then the site's own layer.

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The headings stung. Each h1 and h2 wraps its last word or two in <code><span class="text-accent"></code>, an italic serif… Two pills say "How it works" and "Get started", both on the lint's list.

Source

In September a user, ktlesr, posted a measurement in issue #74 on an earlier version: four landing‑page briefs built with and without the skill… Pure black or white appeared on 40 of 40 pages without it and 14 of 28 with it.

Source