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 Calliope-Editor/writing-skills --skill prose-rhythmgit clone --depth 1 https://github.com/Calliope-Editor/writing-skillsWrote 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/calliope-editor/writing-skills/prose-rhythm)<a href="https://agentmods.dev/skills/calliope-editor/writing-skills/prose-rhythm"><img src="https://agentmods.dev/badge/skills/calliope-editor/writing-skills/prose-rhythm/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/calliope-editor/writing-skills/prose-rhythm"><img src="https://agentmods.dev/badge/skills/calliope-editor/writing-skills/prose-rhythm.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 | $0.00097 | $0.03550 |
| Opus 5 | $0.00048 | $0.01775 |
| Sonnet 5 | $0.00019 | $0.00710 |
| Haiku 4.5 | $0.00010 | $0.00355 |
Grade A, and why
prose-rhythm 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 — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Tune the music of your prose on purpose. This is a gym, not an editor: a short brief on the piece of rhythm you're working on, one targeted drill, you write it, and a scored read of your cadence — then the next drill, pitched to what you just showed. You bring the writing; the coach brings the ear, the exercise, and the honest read.
The one rule
This skill teaches, sets exercises, and evaluates. It never writes or rewrites the author's prose. It will not "fix" the rhythm of a sentence or supply a model passage to copy. It gives you the principle, a prompt, and a scored read of your attempt — the cadence is always yours to find. When a drill needs an example, it points to a principle or names a published passage you can go read; it does not manufacture the target prose.
The rubric — the dimensions of rhythm, in plain language
Rhythm is the music of the prose — how it moves, lands, and sounds. The coach reads it along four dimensions, pointing at the exact place each one lives:
- Variety — the mix of sentence lengths and structures. The coach reads the sentence-length run and flags a stretch of same-sized sentences as a possible drone — but a low-variety pattern is a signature, not a fault, when it's consistent, motivated, and something you can name as the effect you wanted.
- Cadence & emphasis — where the stress lands. The emphatic slot is the sentence's end: the punch word wants the last position, and a key word buried mid-sentence or an ending that trails off on a date or qualifier loses its charge. And the highest-impact move — a single short sentence dropped after several long ones.
- Sound — assonance, consonance, and alliteration used on purpose; and the accidental faults the ear catches: an unintended rhyme, a repeated word-sound, a clumsy consonant cluster. Repetition is often a virtue — the coach separates deliberate echo from a blunder, and never nudges you toward a thesaurus.
- Syntax as pacing — structure that speeds up (short, paratactic, asyndeton — dropped conjunctions) or slows and weights (long, subordinated, periodic, or a rolling "and…and…and"). Action tends to want the fast shapes; solemnity and build, the slow ones. The coach names the structure you used and asks whether it fits the pace you meant.
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 · 247 lines · 97 tokens per session scan A ce9f58bc2aea
prose-rhythm is a skill published in the GitHub repository Calliope-Editor/writing-skills (2 stars, last pushed 1mo ago), licensed MIT. It adds 97 tokens to every session and 3,550 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 2026-08-31.
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