impeccable

A set of instructions for designing and improving frontend interfaces, such as websites, dashboards, forms, and app screens. It guides the agent through making and reviewing working interface code.

In plain words
What is it for?
Creating, redesigning, auditing, polishing, clarifying, optimizing, animating, or adapting frontend pages and components.
Why use it?
It gives interface work a defined process for choosing design details, checking the project context, and refining the result.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/thecodingend/rails-starter/impeccable
Any agent
npx skills add thecodingend/rails-starter --skill impeccable
Clone the repo
git clone --depth 1 https://github.com/thecodingend/rails-starter

Made for: Claude Code, Codex.

Per session 189 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,679 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 80% 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.

ModelPer sessionOnce invoked
Fable 5 $0.00189 $0.05679
Opus 5 $0.00095 $0.02840
Sonnet 5 $0.00038 $0.01136
Haiku 4.5 $0.00019 $0.00568

Measured 2d ago against content hash 14c464236855, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

impeccable 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 2d ago.

The scan reads SKILL.md. This mod also ships 24 executable files (scripts/context-signals.mjs, scripts/context.mjs, scripts/critique-storage.mjs, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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

80% identical to impeccable — 68 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.

.agents/skills/impeccable/SKILL.md · 176 lines

How it starts

The opening of the file, as written. The whole thing — 176 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Designs and iterates production-grade frontend interfaces. Real working code, committed design choices, exceptional craft.

Setup

You MUST do these steps before proceeding:

  1. Run node .agents/skills/impeccable/scripts/context.mjs once per session; if the runtime shows this skill's loaded base directory, run node <skill-base-dir>/scripts/context.mjs instead. Keep cwd/workdir at the user's project, not the skill directory. If the request names or implies a file, route, or app inside a monorepo, infer the concrete path and append --target <path> to the same command. If you've already seen its output in this conversation, do not re-run it. The script either prints the project's PRODUCT.md (and DESIGN.md when present) as a markdown block, or tells you it's missing. Follow whatever it prints. If it reports NO_PRODUCT_MD: divert into reference/init.md first when the user invoked init, teach, craft, or shape, or when their wording clearly maps to one of those from-scratch build flows (for example: "build/create/make a landing page", "design a new app", or "shape a feature"). Captured product context is the point of those flows. For any other command, a scoped evaluate / refine / enhance / fix / iterate request against existing code, do not divert into init. The existing code is the context: proceed with the requested command, infer the register from the surface in focus (step 4), and offer $impeccable init once as a suggestion the user can take later. A missing PRODUCT.md must never block a scoped request. If the output ends with an UPDATE_AVAILABLE directive, follow it (ask the user once about updating, then continue). It never blocks the current task.
  2. If the user invoked a sub-command (craft, shape, audit, polish, ...), you MUST read the command's reference next: reference/<command>.md, or the native variant from the Commands table (e.g. reference/audit.native.md) when the project platform is native (ios / android / adaptive, per the context.mjs directive). One file, not both. Non-optional. The reference defines the command's flow; without it you will skip steps the user expects.
  3. Familiarize yourself with any existing design system, conventions, and components in the code. Read at least one project file (CSS / tokens / theme / a representative component or page). Required even when you've loaded a sub-command reference in step 2. Don't reinvent the wheel; use what's there when it works, branch out when the UX wins.
  4. Read the matching register reference. This is non-optional; skipping it produces generic output. If the project is marketing, a landing page, a campaign, long-form content, or a portfolio (design IS the product), read reference/brand.md. If it is app UI, admin, a dashboard, or a tool (design SERVES the product), read reference/product.md. Pick by first match: (1) task cue ("landing page" vs "dashboard"); (2) surface in focus (the page, file, or route being worked on); (3) register field in PRODUCT.md.
  5. If PRODUCT.md's ## Platform is ios or android, also read reference/<platform>.md (HIG / Material 3 conventions). adaptive (cross-platform, ships both) reads both files. web, absent, or unrecognized: nothing extra to read. context.mjs prints the directive when one applies.
  6. If the project is brand-new (no existing CSS tokens / theme / committed brand colors found in step 3), run node .agents/skills/impeccable/scripts/palette.mjs to receive a brand seed color and composition guidance. This is the anchor for your primary brand color. Compose the rest of the palette (bg, surface, ink, accent, muted) around it per the script's instructions. Use OKLCH throughout. Skip this step only if step 3 found committed brand colors in existing tokens; in that case identity-preservation wins.

Read the full file on GitHub · 176 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.

  1. 2d ago First seen · 176 lines · 189 tokens per session scan A 14c464236855

Subscribe to this mod's changes

impeccable is a skill published in the GitHub repository thecodingend/rails-starter (5 stars, last pushed 8d ago), licensed MIT. It adds 189 tokens to every session and 5,679 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. It is 80% identical to impeccable, differing in 68 lines, and is treated as a copy.

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