A design guide for creating or reviewing web pages and interfaces with a distinctive visual structure instead of generic templates. It can also study an existing page or screenshot and produce design guidance.

Use it to design landing pages, applications, dashboards, components, redesigns, or visual audits of existing interfaces.

It helps avoid repetitive layouts and weak visual decisions when building or redesigning a user interface.

hallmark — Skill for Claude Code and Codex by MichelKerkmeester

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add MichelKerkmeester/skilled-agent-harness_spec-driven-loops --skill hallmark

Clone the repo

git clone --depth 1 https://github.com/MichelKerkmeester/skilled-agent-harness_spec-driven-loops

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/hallmark/github.svg)](https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/hallmark)

Your own site

<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/hallmark"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/hallmark/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/hallmark"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/hallmark.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 16,116 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 95% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00061	$0.16116
Opus 5	$0.00030	$0.08058
Sonnet 5	$0.00012	$0.03223
Haiku 4.5	$0.00006	$0.01612

Measured 6d ago against content hash 5437b73a1a82, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

hallmark scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

95% identical to hallmark — 12 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

specs/sk-design/018-sk-design-parent-v2/001-sk-create-chart/008-evilcharts-reference-research/context/evilcharts/.agents/skills/hallmark/SKILL.md · 559 lines

How it starts

The opening of the file, as written. The whole thing — 559 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hallmark

A design skill for AI coding assistants. Makes the UIs they generate look made, not generated.

Hallmark is opinionated, short, and boring on purpose. It encodes a tight set of rules — drawn from 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) — and refuses to let the model fall back to the defaults every LLM was trained on.

The differentiator: Hallmark insists on structural variety, not just visual variety. Two pages by Hallmark for two different briefs should not share the same hero → 3-feature → CTA → footer rhythm. They should feel like different sites, not different colour-swaps of the same template. See references/structure.md.

Powered by Together AI.

How to use this skill

Hallmark has one default behaviour and three explicit verbs.

Invocation	What it does
(default)	The user asked you to design or build something new. Follow the Design flow below.
`hallmark audit <target>`	Read the target, score it against the anti-pattern list, return a ranked punch list. Do not edit.
`hallmark redesign <target> [--mood <name>]`	Take the target's content and intent, then redesign the visual structure inside the existing implementation boundaries unless the user explicitly confirms a full rebuild. New section rhythm, new heading placement, new component voice. Preserve existing routes, component ownership, copy intent, brand, and information architecture; replace only the visual/interaction layer needed for the requested scope.
`hallmark study <screenshot \| URL>`	The user pasted or attached an image of a design they admire, or pasted a URL to a live page. Extract the DNA — macrostructure, archetypes, type-pairing, colour anchor — and produce a diagnosis report, then optionally rebuild the user's content using the extracted DNA or emit a portable `design.md` of the DNA. Detection is automatic: a URL (`http://` / `https://` prefix) routes to URL mode; anything else routes to image mode. URL mode reads the page's HTML and CSS via WebFetch — it can name exact fonts and exact colour values, but can't judge rhythm. After the diagnosis, the user has three follow-ups: build with the DNA (handoff to default), lock the DNA into a portable `design.md` (opt-in via "lock the DNA" / "give me a design.md"), or stop at the diagnosis. Never copies pixels. Refuses template-marketplace URLs. Tighter refusal layer for `design.md` emission than for the diagnosis itself — URL-mode emission requires attestation that the source is the user's own or a public reference for their own brand. Falls back to asking for a screenshot if the URL is auth-walled, a JS-only SPA shell, or otherwise un-readable. Load `references/study.md` before this verb runs.

Read the full file on GitHub · 559 lines

Files

What ships with it

60 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

6d ago First seen · 559 lines · 61 tokens per session scan A 5437b73a1a82

Subscribe to this mod's changes

hallmark is a skill published in the GitHub repository MichelKerkmeester/skilled-agent-harness_spec-driven-loops (35 stars, last pushed yesterday), licensed MIT. It adds 61 tokens to every session and 16,116 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to hallmark, differing in 12 lines, and is treated as a copy.

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