Borrowing it
Nothing to install: this file belongs to aospbooks/aosp-internal-book. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/aospbooks/aosp-internal-book/main/.claude/skills/book-writer/SKILL.mdgit clone --depth 1 https://github.com/aospbooks/aosp-internal-bookWrote 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/aospbooks/aosp-internal-book/book-writer)<a href="https://agentmods.dev/skills/aospbooks/aosp-internal-book/book-writer"><img src="https://agentmods.dev/badge/skills/aospbooks/aosp-internal-book/book-writer/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/aospbooks/aosp-internal-book/book-writer"><img src="https://agentmods.dev/badge/skills/aospbooks/aosp-internal-book/book-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00104 | $0.02944 |
| Opus 5 | $0.00052 | $0.01472 |
| Sonnet 5 | $0.00021 | $0.00589 |
| Haiku 4.5 | $0.00010 | $0.00294 |
Grade A, and why
book-writer 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 11d 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 — 226 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Book Writer
Write source-code-referenced technical books in Markdown with Mermaid diagrams, served as a ProperDocs website. Covers chapter structure, content flow, diagram syntax, and keeping the ProperDocs site in sync with content changes.
ProperDocs Site Maintenance
The book is served via ProperDocs (a MkDocs fork) with the Material theme. When chapter content changes, the site configuration must stay in sync. Forgetting this breaks navigation or hides new chapters from readers.
When you add a new chapter
- Create
NN-slug.mdwith the chapter template below - Add a nav entry to
properdocs.ymlin the correct Part section:- "N. Chapter Title": NN-slug.md - Create a symlink in
docs/:ln -sf "../NN-slug.md" "docs/NN-slug.md" - Add a chapter entry to
llms.txtin the correct Part section, in chapter order:- [Chapter N: Title](https://aospbooks.github.io/aosp-internal-book/NN-slug/): one-line description of what the chapter covers - If the chapter number changes existing chapters, renumber the affected
properdocs.ymlentries andllms.txtURLs too - Add the new chapter slug to
agents/_content/manifest.tomlunder the right Part (and create a new Part entry there +agents/_content/parts/<slug>/SKILL.mdif the chapter belongs to a brand-new Part), then runpython3 agents/build.pyand commit the regeneratedagents/<platform>/trees.
When you remove a chapter
- Delete the
.mdfile - Remove its entry from
properdocs.ymlnav - Remove the symlink from
docs/ - Remove the matching
llms.txtentry - Renumber subsequent chapters if needed (in filenames,
properdocs.yml,llms.txt, and section headings inside the files) - Remove the chapter slug from
agents/_content/manifest.toml, then runpython3 agents/build.pyand commit the regeneratedagents/<platform>/trees.
When you rename or reorder chapters
- Rename the
.mdfile - Update the
properdocs.ymlnav entry (both the label and the filename) - Update the
docs/symlink - Update the
llms.txtentry (label, URL slug, and the one-line description if scope changed) - Update all
## N.xsection headings inside the file to match the new chapter number - Update the chapter slug in
agents/_content/manifest.toml(and the relevant Part'sSKILL.mddescription if scope shifted), then runpython3 agents/build.pyand commit the regeneratedagents/<platform>/trees.
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.
- 11d ago First seen · 226 lines · 104 tokens per session scan A bdd5a277580b
book-writer is a skill published in the GitHub repository aospbooks/aosp-internal-book (131 stars, last pushed 12d ago), licensed Apache-2.0. It adds 104 tokens to every session and 2,944 once invoked, about $0.0005 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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