design-system

design-system is a skill for Claude Code, Codex from LucasDuys/forge. It costs 21 tokens per session (1,951 once invoked), scanned A, original, MIT.

A shared DESIGN.md file that records a project's visual rules, such as colors, fonts, spacing, components, and responsive layouts, for Forge agents to follow.

In plain words
What is it for?
It is for guiding agents while they create or update screens, buttons, forms, layouts, and other user-interface elements.
Why use it?
It helps keep interface changes consistent when different agents work on the same project.

Skill for Claude CodeCodex

Part of the forge plugin — 10 skills, 13 commands, 9 agents, 3 hooks shipped together

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/lucasduys/forge/design-system
Any agent
npx skills add LucasDuys/forge --skill design-system
Clone the repo
git clone --depth 1 https://github.com/LucasDuys/forge

Made for: Claude Code, Codex.

Or install forge, the plugin that ships this one along with the rest of its 10 skills, 13 commands, 9 agents, 3 hooks.

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.

agentmods badge for design-system

README.md
[![agentmods](https://agentmods.dev/badge/skills/lucasduys/forge/design-system.svg)](https://agentmods.dev/skills/lucasduys/forge/design-system)
Your own site
<a href="https://agentmods.dev/skills/lucasduys/forge/design-system"><img src="https://agentmods.dev/badge/skills/lucasduys/forge/design-system.svg" alt="Measured on agentmods" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,951 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00021 $0.01951
Opus 5 $0.00010 $0.00975
Sonnet 5 $0.00004 $0.00390
Haiku 4.5 $0.00002 $0.00195

Measured 4d ago against content hash cf3a557a21d9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

design-system 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 4d 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.

skills/design-system/SKILL.md · 210 lines

How it starts

The opening of the file, as written. The whole thing — 210 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Design System Skill

This skill integrates DESIGN.md-based design specifications into the Forge workflow. When a project has a DESIGN.md file, all UI-related tasks automatically inherit design constraints, ensuring brand consistency across parallel agent execution.

What is DESIGN.md?

DESIGN.md is a standardized markdown format for design specifications that AI agents can read and follow. It contains:

  1. Visual Theme and Atmosphere -- brand philosophy and design mood
  2. Color Palette -- semantic color definitions (Primary, Error, Surface, etc.) with hex values
  3. Typography Hierarchy -- font families, weights, sizes for H1-H6, body, caption
  4. Component Styling -- button specs, card styling, input borders, border radius, shadows
  5. Layout Principles and Spacing -- spacing scale (base unit), margin/padding rules, grid conventions
  6. Depth and Elevation Systems -- shadow definitions, z-index hierarchies
  7. Design Guardrails and Anti-Patterns -- what NOT to do, brand identity boundaries
  8. Responsive Behavior Parameters -- mobile/tablet/desktop breakpoints, scaling rules
  9. Agent Prompt Guide -- quick reference for AI agents to maintain consistency

Detection

At the start of brainstorming or planning, check for an existing DESIGN.md:

# Check common locations
ls DESIGN.md design.md docs/DESIGN.md 2>/dev/null

If found, load it and reference it throughout the workflow.

Integration with Forge Phases

Brainstorming Phase

When /forge brainstorm runs for a project with UI components:

  1. Check for DESIGN.md -- if it exists, reference it during spec generation
  2. If no DESIGN.md exists, ask the user during the Q&A phase:

    Does this project have a design system or brand guidelines? A) Yes, I have a DESIGN.md file (specify path) B) I want to base it on an existing brand (specify which -- e.g., Stripe, Linear, Claude) C) No specific design requirements -- use sensible defaults D) I'll provide design specs later

Read the full file on GitHub · 210 lines

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. 4d ago First seen · 210 lines · 21 tokens per session scan A cf3a557a21d9

Subscribe to this mod's changes

design-system is a skill published in the GitHub repository LucasDuys/forge (55 stars, last pushed 1mo ago), licensed MIT. It adds 21 tokens to every session and 1,951 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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