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 frankxai/claude-skills-library --skill arcanea-book-covergit clone --depth 1 https://github.com/frankxai/claude-skills-libraryWrote 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/frankxai/claude-skills-library/arcanea-book-cover)<a href="https://agentmods.dev/skills/frankxai/claude-skills-library/arcanea-book-cover"><img src="https://agentmods.dev/badge/skills/frankxai/claude-skills-library/arcanea-book-cover/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/frankxai/claude-skills-library/arcanea-book-cover"><img src="https://agentmods.dev/badge/skills/frankxai/claude-skills-library/arcanea-book-cover.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 | $0.00091 | $0.02163 |
| Opus 5.5 | $0.00036 | $0.00865 |
| Sonnet 5.5 | $0.00018 | $0.00433 |
| Haiku 4.5 | $0.00009 | $0.00216 |
Grade A, and why
arcanea-book-cover scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl -s "https://generativelanguage.googleapis.com/v1beta/models/$MODEL:generateContent?key=$GEMINI_API_KEY" \ How it starts
The opening of the file, as written. The whole thing — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arcanea Book Cover Design Skill
Generate premium book covers by thinking deeply about the book first, then translating that thinking into a precision image prompt. NB2 is default. NB Pro only when user specifies "premium" or "hero".
The 5-Phase Method
Do NOT skip phases. The thinking is the skill. The generation is the reward.
Phase 1: READ THE BOOK (or its architecture)
Before writing any prompt, you must understand:
- Central tension — What does the protagonist fight against? What internal conflict mirrors the external?
- Emotional register — Is this grief-heavy? Wonder-heavy? Dread-heavy? A dark comedy? Bittersweet? Name it precisely.
- Iconic image — What ONE visual moment defines the book? The image a reader would tattoo on themselves.
- Genre expectations vs subversion — What do readers of this genre expect? What should you give them, and what should you withhold?
- Color emotional key — What color (singular) carries the book's feeling?
If the book has a book.yaml or outline, read them. If the book has existing chapters, read at least one opening and one pivotal scene.
Phase 2: PULL BEST PRACTICES
Top book cover designers operate on these principles. Keep them active during prompt design:
Chip Kidd's Rules:
- One idea, one image, one emotion
- The cover is a question, not an answer — it should make readers curious, not satisfied
- Text and image are one unit — typography is 50% of the cover
- Don't illustrate the plot. Illustrate the feeling.
Peter Mendelsund's Rules:
- Covers are "visual metaphors, not visual illustrations"
- Abstraction > literalism when the book is literary
- The reader should finish the book and look at the cover and think "of course"
- White space is content
Coralie Bickford-Smith's Rules (Penguin Classics):
- Pattern + symbol > scene (for literary)
- Limited palette (2-4 colors max)
- Typography must be the hero on pattern-based covers
- Consistency within a series, uniqueness between series
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.
- 1mo ago Changed 13b4e5ca43c3
- 1mo ago First seen · 181 lines · 91 tokens per session scan A 7d69e102c7ad
arcanea-book-cover is a skill published in the GitHub repository frankxai/claude-skills-library (47 stars, last pushed yesterday), licensed MIT. It adds 91 tokens to every session and 2,163 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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