prose

prose is a skill for Claude Code, Codex from tslateman/duet. It costs 42 tokens per session (1,100 once invoked), scanned A, original, MIT.

Writing guidance based on Strunk's rules for clear, concise English.

In plain words
What is it for?
Improving documentation, commit messages, error messages, interface text, comments, reports, and other drafts.
Why use it?
It helps remove unnecessary words and make writing easier to understand.

Skill for Claude CodeCodex

Part of the duet plugin — 25 skills, 6 commands, 1 agent shipped together

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 skills/tslateman/duet/prose
Any agent
npx skills add tslateman/duet --skill prose
Clone the repo
git clone --depth 1 https://github.com/tslateman/duet

Made for: Claude Code, Codex.

Or install duet, the plugin that ships this one along with the rest of its 25 skills, 6 commands, 1 agent.

Wrote 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.

agentmods badge for prose

README.md
[![agentmods](https://agentmods.dev/badge/skills/tslateman/duet/prose.svg)](https://agentmods.dev/skills/tslateman/duet/prose)
Your own site
<a href="https://agentmods.dev/skills/tslateman/duet/prose"><img src="https://agentmods.dev/badge/skills/tslateman/duet/prose.svg" alt="Measured on agentmods" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,100 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00042 $0.01100
Opus 5 $0.00021 $0.00550
Sonnet 5 $0.00008 $0.00220
Haiku 4.5 $0.00004 $0.00110

Measured 3d ago against content hash 908ab2c13670, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prose 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 3d 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.

skills/prose/SKILL.md · 110 lines

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.

Writing Clearly and Concisely

Overview

William Strunk Jr.'s The Elements of Style (1918) teaches you to write clearly and cut ruthlessly.

WARNING: references/elements-of-style.md consumes ~12,000 tokens. Read it only when writing or editing prose.

When to Use This Skill

Use this skill whenever you write prose for humans:

  • Documentation, README files, technical explanations
  • Commit messages, pull request descriptions
  • Error messages, UI copy, help text, comments
  • Reports, summaries, or any explanation
  • Editing to improve clarity
  • Tightening or sharpening a draft that runs long

If you're writing sentences for a human to read, use this skill.

Limited Context Strategy

When context is tight:

  1. Write your draft using judgment
  2. Dispatch a subagent with your draft and references/elements-of-style.md
  3. Have the subagent copyedit and return the revision

All Rules

Elementary Rules of Usage (Grammar/Punctuation)

  1. Form possessive singular by adding 's
  2. Use comma after each term in series except last
  3. Enclose parenthetic expressions between commas
  4. Comma before conjunction introducing co-ordinate clause
  5. Don't join independent clauses by comma
  6. Don't break sentences in two
  7. Participial phrase at beginning refers to grammatical subject

Elementary Principles of Composition

  1. One paragraph per topic
  2. Begin paragraph with topic sentence
  3. Use active voice
  4. Put statements in positive form
  5. Use definite, specific, concrete language
  6. Omit needless words
  7. Avoid succession of loose sentences
  8. Express co-ordinate ideas in similar form
  9. Keep related words together
  10. Keep to one tense in summaries
  11. Place emphatic words at end of sentence

Section V: Words and Expressions Commonly Misused

Alphabetical reference for usage questions

Editing by Subtraction

Sharpening a draft means removing everything that does not serve the core point. Not rewriting. Not adding "voice." Cutting.

Read the full file on GitHub · 110 lines

Files

What ships with it

2 files 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.

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. 3d ago First seen · 110 lines · 0 tokens per session scan A 908ab2c13670

Subscribe to this mod's changes

prose is a skill published in the GitHub repository tslateman/duet (1 stars, last pushed 6d ago), licensed MIT. It adds 42 tokens to every session and 1,100 once invoked, about $0.0002 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.