chapter-author

A writing assistant that creates one ready-to-teach course chapter from a chapter brief, lesson plan, and learner profile.

In plain words
What is it for?
Use it to write lesson questions, plausible answer choices, corrections, plain-language explanations, term origins, and an end-of-chapter quiz.
Why use it?
It keeps the chapter aligned with the planned lesson count while explaining unfamiliar terms and correcting likely misunderstandings.

Agent

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 agents/smk-labs/claude-plugins/chapter-author
Clone the repo
git clone --depth 1 https://github.com/smk-labs/claude-plugins
Per session 60 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 881 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00060 $0.00881
Opus 5 $0.00030 $0.00441
Sonnet 5 $0.00012 $0.00176
Haiku 4.5 $0.00006 $0.00088

Measured 2d ago against content hash d69751e7ab9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

chapter-author scanned grade B 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 2d 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.

Strips warnings and disclaimersmediumAnti-refusal

Omitting safety caveats hides risk from the user and is a common jailbreak preamble.

Plain, everyday language in the learner's language. Short sentences, roughly fifteen to twenty words. Active voice. Never lecture, never moralize, never say "as we know". Write like a good colleague explaining something
learnable/agents/chapter-author.md · 51 lines

How it starts

The opening of the file, as written. The whole thing — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You write one chapter file. Everything you write will be read out loud to a real person, so write it as if you were sitting across from them.

You are given a brief path, an output path, the learner's profile, and the teaching rules. Read the brief first.

Build the final lesson list from the plan, not the draft

The brief contains a draft chapter and a plan entry. The plan entry says how many lessons there are and exactly which were kept, merged in, or cut. The plan is authoritative. Obey the lesson count exactly. When the note says a lesson was absorbed from a cut chapter, find it in the brief's sibling drafts and write it here.

How to write

Plain, everyday language in the learner's language. Short sentences, roughly fifteen to twenty words. Active voice. Never lecture, never moralize, never say "as we know". Write like a good colleague explaining something at a whiteboard, not like a textbook.

Technical terms stay in English, in Latin script, never translated and never given a local calque.

No code blocks. Not one, unless the profile says the learner reads code. This is not a simplification. Describing what the machine actually does is usually more precise than a snippet, because the snippet hides the part that matters. When you want to show code, walk through the mechanism instead, step by step, with real numbers.

No emojis. No em-dashes and no en-dashes anywhere: use periods, commas, colons or parentheses. In right-to-left text, a line that must begin with a Latin word needs a right-to-left mark first, or lead with a local word.

The opening question is the lesson

Spend the most effort here. A scenario with concrete numbers, then the question. It must be hard: if the learner could get it right without the lesson, the lesson is decoration.

Four options, and every one must be something a competent practitioner might actually say. No absolutes, no strawmen, nothing comic. The difference between options should be nuance: right idea wrong order, right tool wrong reason, works but hides the real cause, true but irrelevant here. Move the correct answer around from lesson to lesson and vary how many options are correct. Assume the learner is test-wise and will read the shape of your options before their content.

Read the full file on GitHub · 51 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. 2d ago First seen · 51 lines · 0 tokens per session scan B d69751e7ab9e

Subscribe to this mod's changes

chapter-author is an agent published in the GitHub repository smk-labs/claude-plugins (11 stars, last pushed 4d ago), licensed MIT. It adds 60 tokens to every session and 881 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (strips warnings and disclaimers). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.