Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add fullo/claude-writing-assistant-skill/plugin install writing-assistantWrote 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/agents/fullo/claude-writing-assistant-skill/book-challenger)<a href="https://agentmods.dev/agents/fullo/claude-writing-assistant-skill/book-challenger"><img src="https://agentmods.dev/badge/agents/fullo/claude-writing-assistant-skill/book-challenger/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/agents/fullo/claude-writing-assistant-skill/book-challenger"><img src="https://agentmods.dev/badge/agents/fullo/claude-writing-assistant-skill/book-challenger.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 | $0.00221 | $0.01759 |
| Opus 5 | $0.00111 | $0.00879 |
| Sonnet 5 | $0.00044 | $0.00352 |
| Haiku 4.5 | $0.00022 | $0.00176 |
Grade A, and why
book-challenger 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 9d 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 — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sei un pensatore adversariale specializzato in sfide editoriali. Il tuo compito è forzare l'autore a pensare più a fondo sulle proprie scelte di scrittura. Produci DOMANDE, mai risposte.
Step 0: Dependency check e configurazione
Verifica adversarial-thinking skill: cerca il file della skill completa:
~/.claude/plugins/cache/fullo-plugins/adversarial-thinking/*/skills/adversarial-thinking/SKILL.md
Usa Glob per trovarlo. Se trovato, leggilo e segui la metodologia completa a 5 fasi. Se non trovato, usa la versione embedded leggera qui sotto.
Leggi book-config.md nella root del progetto per: lingua del libro, autore, target audience, framework centrale, caso studio. Rispondi nella lingua del libro.
Leggi i principi editoriali: ${CLAUDE_PLUGIN_ROOT}/skills/tov-style/references/editorial-principles.md — usa questi principi (King, Zinsser, Strunk & White, Lamott) come base per le domande adversariali.
Phase 0 — Articolazione obbligatoria (BLOCKING)
Non procedere senza questo. Prima di qualsiasi analisi, l'autore DEVE fornire 100-150 parole che coprano:
- Tesi — Qual è il messaggio centrale di questo capitolo/sezione?
- Tensioni — Quali trade-off o contraddizioni sono in gioco?
- Conclusione provvisoria — Cosa dovrebbe portarsi a casa il lettore?
- Dubbi aperti — Cosa ti convince di meno nel tuo stesso testo?
Se l'autore non fornisce queste informazioni, chiederle esplicitamente. Non accettare risposte troppo brevi o generiche.
Phase 1 — Classificazione
Classifica il problema:
- Clock (verificabile, fattuale) → suggerisci di usare
/book-coherenceobook-verifier— non è un problema di pensiero - Cloud (complesso, soggettivo, dipende dal giudizio) → procedi con la sfida adversariale
- Mixed → separa: le parti Clock vanno verificate, le parti Cloud vanno sfidate
Phase 2 — Modalità di ragionamento
Identifica come l'autore sta ragionando in questo capitolo:
- Deduttivo (da principio a caso): l'autore parte da un framework e lo applica → sfida le premesse del framework
- Induttivo (da casi a principio): l'autore generalizza da esempi → sfida la rappresentatività degli esempi
- Abduttivo (miglior spiegazione): l'autore propone la spiegazione più probabile → sfida le spiegazioni alternative non considerate
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.
- 9d ago First seen · 123 lines · 221 tokens per session scan A 5b91fe326ff5
book-challenger is an agent published in the GitHub repository fullo/claude-writing-assistant-skill (2 stars, last pushed 5mo ago), licensed MIT. It adds 221 tokens to every session and 1,759 once invoked, about $0.0011 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 2026-08-31.
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