mx: Skill for Claude Code

.agents/skills/mx-comments/SKILL.md

mx-comments is a skill for Claude Code from webern/mx. It costs 22 tokens per session (479 once invoked), scanned A, original, MIT.

A writing guide for code comments and library documentation, aimed at both musicians who code and developers who write music software.

In plain words
What is it for?
It is for writing or reviewing comments and documentation in the library, especially its public API. It encourages plain language and avoids exposing private conversation details.
Why use it?
It helps comments stay clear, useful to newcomers, and stable as the code changes.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: installed under .agents/ (shared by several agents).

This is webern/mx's own configuration. It tells Claude Code how to work on mx itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mx configures →

View source ↗ webern/mx
Reuse

Borrowing it

Nothing to install: this file belongs to webern/mx. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/webern/mx/main/.agents/skills/mx-comments/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/webern/mx

Made for: Claude Code.

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 mx-comments

README.md
[![agentmods](https://agentmods.dev/badge/skills/webern/mx/mx-comments/github.svg)](https://agentmods.dev/skills/webern/mx/mx-comments)
Your own site
<a href="https://agentmods.dev/skills/webern/mx/mx-comments"><img src="https://agentmods.dev/badge/skills/webern/mx/mx-comments/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.

agentmods 80×15 button for mx-comments

Your own site · 80×15
<a href="https://agentmods.dev/skills/webern/mx/mx-comments"><img src="https://agentmods.dev/badge/skills/webern/mx/mx-comments.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 479 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00022 $0.00479
Opus 5.5 $0.00009 $0.00192
Sonnet 5.5 $0.00004 $0.00096
Haiku 4.5 $0.00002 $0.00048

Measured 2mo ago against content hash 1b186fcebd79, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mx-comments 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 2mo 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.

.agents/skills/mx-comments/SKILL.md · 48 lines

What it actually says

/mx-comments

Code comments are meant to help a developer or coding agent who is unfamiliar with this codebase understand how it works.

Audience:

  • A musician, a composer, who happens to also like writing code.
  • A software developer who happens to also like writing music.

Things to remember:

  • Do not leak particulars of a user session, or your LLM context window, into code comments or repository writing. Code comments are not an extension of the conversation you had with the user.
  • Code comments should not churn every time the code changes. Do not list each item that a function touches in its documentation such that you have to add to the list every time you edit the function's behavior. Write more generally so that the code comment can outlive future tweaks to the function.

Avoid implementation details in the headers of src/mx/api. Those are particularly musician-facing code comments. The more maintainer facing comments go in the deeper layers of the system.

Please

Use plain grammar and simple sentence structure. Use common vocabulary that a human composer or software engineer would use in conversation. When the first half of a sentence is enough, don't add a continuation of the sentence that says the same thing in counterpoint.

Pretend you are humble engineer explaining how something works, or why it is the way that it is, without trying to look clever. Go out of your way to write with humility and to be easily understood. You are not here to show how smart you are. Do not increase the cognitive load of those trying to read your work.

Banned Words and Structures

  • "knob": you invented this and you overuse it. stop.
  • Don't say "writes no attribute". That's a weird non-human style. Instead say "does not write an attribute". More generally do not say "{{verbs}} no {{noun}}". Instead say "does not {{verb}} a {{noun}}"
  • "load bearing": it's weird, you invented it, and you overuse it.
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. 2mo ago First seen · 48 lines · 22 tokens per session scan A 1b186fcebd79

Subscribe to this mod's changes

mx-comments is a skill published in the GitHub repository webern/mx (93 stars, last pushed yesterday), licensed MIT. It adds 22 tokens to every session and 479 once invoked, about $0.0001 per session on Opus 5.5. 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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