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.
npx skills add oborchers/fractional-cto --skill color-theory-applicationgit clone --depth 1 https://github.com/oborchers/fractional-ctoWrote 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.
[](https://agentmods.dev/skills/oborchers/fractional-cto/color-theory-application)<a href="https://agentmods.dev/skills/oborchers/fractional-cto/color-theory-application"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/color-theory-application/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.
<a href="https://agentmods.dev/skills/oborchers/fractional-cto/color-theory-application"><img src="https://agentmods.dev/badge/skills/oborchers/fractional-cto/color-theory-application.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00095 | $0.01537 |
| Opus 5.5 | $0.00038 | $0.00615 |
| Sonnet 5.5 | $0.00019 | $0.00307 |
| Haiku 4.5 | $0.00010 | $0.00154 |
Grade A, and why
color-theory-application 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Color Is a System, Not a Feeling — Build It with HSL and Constrain It with Rules
Color decisions made by intuition drift over time. Color decisions made by system scale indefinitely. Pick hues with harmony theory, generate shades with lightness math, enforce contrast with WCAG, and assign meaning with semantic tokens.
HSL as the Designer's Model
Use HSL (Hue, Saturation, Lightness) for all color work. RGB and hex are machine formats — HSL maps to how humans perceive color.
| Task | HSL | RGB/Hex |
|---|---|---|
| Make a color lighter | Increase L | Guess and check all 3 channels |
| Create a complementary color | Rotate H by 180 degrees | No intuitive relationship |
| Generate a shade scale | Fix H and S, vary L in steps | Manual trial and error |
For perceptual uniformity in production, consider OKLCH (oklch(L C H)) — it corrects HSL's lightness distortion across hues.
The 60-30-10 Rule
| Tier | Percentage | Role | Typical Choice |
|---|---|---|---|
| Dominant | 60% | Backgrounds, surfaces | Neutral (white, light gray, dark gray) |
| Secondary | 30% | Cards, sidebars, borders | Tinted neutral or subdued brand |
| Accent | 10% | CTAs, highlights, active states | Saturated brand color |
Limit to 3-6 distinct hue families. Most successful SaaS products use a single brand hue plus neutrals and semantic colors.
Shade Scale Generation
Generate 9 steps (50-900) by fixing hue, varying lightness, and reducing saturation 5-15% at extremes.
| Step | Lightness | Use Case | Step | Lightness | Use Case |
|---|---|---|---|---|---|
| 50 | 95-97% | Subtle backgrounds | 500 | 45-50% | Base color |
| 100 | 90-92% | Light backgrounds | 600 | 38-42% | Hover states |
| 200 | 82-85% | Borders, dividers | 700 | 28-32% | Active/pressed |
| 300 | 70-75% | Disabled states | 800 | 20-23% | Dark text |
| 400 | 58-62% | Placeholder text | 900 | 12-15% | Headings |
What ships with it
1 file 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.
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.
- 5d ago First seen · 110 lines · 95 tokens per session scan A e8ac8b9bb6c1
color-theory-application is a skill published in the GitHub repository oborchers/fractional-cto (32 stars, last pushed 5d ago), licensed MIT. It adds 95 tokens to every session and 1,537 once invoked, about $0.0004 per session on Opus 5.5. 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 2026-10-13.
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