Hallmark
Nutlope/hallmarkA 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.
Recommended
Check first Depth 5/5
Impeccable Claude skills
A design skill with 24 commands (polish, bolder, critique, audit, harden and more), a 62-rule deterministic slop detector and an optional edit hook.
Our verdict Recommended with caveats
A deep, popular design toolkit, but it downloads a checksum-verified engine binary, can install an unsandboxed edit hook and has opt-out telemetry, so read the setup before running npx impeccable install.
What Impeccable does
Impeccable gives a coding agent a vocabulary for design work. You run /impeccable init once so the agent writes a PRODUCT.md (who it is for, constraints), optionally /impeccable document to capture the existing visual system in DESIGN.md, and then name a command and a target, such as critique the onboarding flow or polish settings. The 24 commands are grouped: steer (bolder, quieter, distill, colorize, typeset, layout, animate, delight, overdrive), review (critique gives a scored UX review, audit gives a ranked technical report on accessibility, performance, theming and responsiveness), finish (polish, harden, clarify, adapt, optimize, onboard), iterate live (pick an element in the browser and cycle variants) and plan and set up (shape, init, document, extract).
Under the commands is a deterministic detector with 62 rules for AI-looking tells and quality problems, which runs through a bundled impeccable launcher with no LLM or API key. The launcher downloads a prebuilt engine binary and checks it against a checksum file. A per-project hook can run the detector after UI file edits. The skill folder is one large skill (about 12 KB of instructions) with some 47 reference files, plus helper scripts for the live mode, with copies installed for around 20 agent harnesses. The README says it began from Anthropic's frontend-design skill.
Good for
- Reviewing and refining an existing interface with named moves such as polish, harden or distill
- Catching common AI design tells automatically after edits
- Teams that want PRODUCT.md and DESIGN.md context files shared across agents
Not for
- Teams that cannot allow a downloaded binary or an edit hook in their agent
- Greenfield pages where you want a themed, opinionated starting point (the README itself says it is strongest on existing interfaces)
What's inside depth 4/5
One 12 KB SKILL.md backed by about 47 reference files for each command and platform, helper scripts, an engine with checksums and a tests folder, though the skill folders ship no evals.
- Skills
- 26
- Reference docs
- 1034
- Scripts
- 110
- Tests / evals
- 0
- Templates
- 0
- Avg SKILL.md
- 9.8 KB
Counted from the repository file tree. How we score depth.
Dependencies and costs
- Node.js for
npx impeccable installand the launcher - A downloaded engine binary for the deterministic detector and live mode
- A running dev server for live element-picking mode
- Telemetry: When a new design starts, the skill fetches visual directions from the impeccable.style catalog; turning telemetry off does not stop that request but stops the anonymous record of which directions were shown and chosen. Disable with
npx impeccable telemetry off, DO_NOT_TRACK=1 or "telemetry": false in .impeccable/config.json. The README says project names, files, code and PRODUCT.md are never sent.
Security review
Broad accessThis skill asks for more access than most, or sends data to another service. That is usually a design choice rather than bad intent, but you should know before you install it.
- Loads instructions from a server at run timeFor new designs the skill tells the agent to run
impeccable concept-seedand follow what it prints; the README says the skill fetches visual directions from the impeccable.style catalog, and the launcher/engine that produces that output is not in the files we have..claude/skills/impeccable/reference/new-work.md:52
A frontend design skill with many sub-commands, a design-detector hook and a live mode that injects a picker overlay into your dev server's HTML. It works through an impeccable launcher and engine binary that are downloaded on first use and not available to us, runs npx impeccable unpinned (pre-approved in several harness copies), sends anonymous design-choice telemetry unless you turn it off, and fetches its direction catalog from impeccable.style. The installer-offered hook runs unsandboxed with your environment.
Worth knowing
- Sends usage data by default (can be turned off)An anonymous record of which design directions were shown and chosen is sent to impeccable.style by default (project names, files, code and PRODUCT.md are said never to be sent); disable with
npx impeccable telemetry off, DO_NOT_TRACK=1 or "telemetry": false, though the catalog fetch itself still happens.README.md:209 - Runs remote code at an unpinned versionInstall and use run
npx impeccable install/npx impeccable detect(unpinned), and the launcher downloads an engine binary into ~/.impeccable/bin that is checked against engine-checksums.txt before first run.README.md:95 - Changes files outside your projectThe installer offers a design-detector hook written into .claude/settings.local.json, ~/.claude/settings.json, .codex/hooks.json, .cursor/hooks.json, .github/hooks/impeccable.json or .gemini/settings.json; the reference says the hook runs the engine unsandboxed with the agent's environment and network access, and README notes hooks run even when the model's commands are denied..claude/skills/impeccable/reference/hooks.md:23
- Makes network requests
impeccable detect <url>drives an installed Chrome/Edge to scan a page, live mode injects a script into your dev-server HTML that talks to a local helper on localhost:8400, and the catalog is fetched from impeccable.style.README.md:80 - Relies on a CLI or package we could not reviewEverything runs through the
impeccablelauncher and a downloaded engine binary (scripts/impeccable, impeccable.cmd, VERSION, font-index.json) which are not among the files we have..claude/skills/impeccable/SKILL.md:19
What we checked
The repository (4439 files) on Oct 29, 2026. Not a full review: 3228 of 4439 files were not downloaded (large repository; we reviewed the skill folders); we read 3 of 88 code files; it relies on code outside the repository: The impeccable launcher scripts (scripts/impeccable, impeccable.cmd), the downloaded engine binary, engine-checksums.txt, VERSION and font-index.json: 3228 readable files in the repo were not available to us; npm package impeccable (npx impeccable install/detect/update); Remote catalog and telemetry endpoint at impeccable.style.
NVIDIA SkillSpector static scan: 367 pattern hits (Excessive Agency 150, Supply Chain 72, MCP Rug Pull 65, Anti-Refusal 37, Agent Snooping 24, Memory Poisoning 19). The 'concealed executable' and 'network capability' hits are the four browser-side live-mode scripts (one vendored modern-screenshot library) copied into each harness folder; the three 'incomplete referenced artifact' hits are the scanner not following SKILL.md links to existing reference files; 'do not judge', 'without warning' and similar anti-refusal hits are phrases in design guidance; '~/.claude/settings.json' is the documented hook install location.
A review, not a certification. Skills change after we check them — read the files before installing.
License
Apache-2.0 — commercial use allowed.
Can it run unattended?
Not really. It is built around interactive steering and review of one target at a time, with live mode needing a person to pick variants.
Skills in this repository
| Skill | Installs |
|---|---|
| impeccable | 369K |
| polish | 85K |
| critique | 83K |
| audit | 82K |
| animate | 82K |
| adapt | 82K |
| clarify | 81K |
| optimize | 81K |
| colorize | 81K |
| bolder | 80K |
| delight | 80K |
| distill | 79K |
| quieter | 79K |
| typeset | 65K |
| overdrive | 63K |
Linked skills have their own review.
Alternatives to Impeccable
Taste Skill
Leonxlnx/taste-skillAn 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
nextlevelbuilder/ui-ux-pro-max-skillA design skill backed by searchable style, palette and font catalogs, with a design-system generator and five companion design skills.
Recommended
Check first Depth 4/5
Anthropic Agent Skills
anthropics/skillsAnthropic's reference skills repo: 20 skills including document tools (docx, pptx, xlsx, pdf), frontend-design, skill-creator and mcp-builder.
Recommended
Check first Depth 4/5
FAQ
What is Impeccable?
Impeccable is a design skill for coding agents that adds a command vocabulary (polish, bolder, critique, audit, harden, distill and others), a reviewer, and a rule-based detector for AI-generated design tells. It works with Claude Code, Cursor, Codex, Copilot, Gemini CLI and many other agents.
How do I install Impeccable?
From your project root run npx impeccable install, reload your coding tool, then run /impeccable init (or $impeccable init on Codex). The init step writes a PRODUCT.md that later commands read.
Is Impeccable safe to install?
The skill text is mostly instructions, and the detector needs no LLM or API key. It does download a checksum-verified engine binary, can add an edit hook that runs unsandboxed, and sends opt-out catalog telemetry, so review those three points and disable what you do not want.
Impeccable vs Hallmark: which one?
Impeccable is strongest at critiquing and refining existing interfaces with named commands. Hallmark deals a theme from fifty options and builds new pages under a fixed rule floor with its own linter. Use Impeccable for iteration and Hallmark for a fresh build.
Sources: GitHub repository (stars, license, file tree, last push Oct 29, 2026); install counts from skills.sh via Best Skills (CC BY 4.0). Review based on the README and SKILL.md files as published.