music-composer

music-composer is an agent for Claude Code from AgriciDaniel/claude-music. It costs 69 tokens per session (1,707 once invoked), scanned A, original, MIT.

A music-composition planning agent for ACE-Step 1.5 that turns a rough idea or partial specification into a structured audio-generation plan.

In plain words
What is it for?
Use it to prepare captions, lyrics, musical settings, language, task type, quality level, and model choices for the parent audio-generation process.
Why use it?
It fills in musical decisions that a short prompt may leave open, such as lyrics structure, tempo, key, duration, and generation mode.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the claude-music plugin — 12 skills, 1 agent shipped together

Good fit Use it to prepare captions, lyrics, musical settings, language, task type, quality level, and model choices for the parent audio-generation process.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/agricidaniel/claude-music/music-composer
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.

Clone the repo
git clone --depth 1 https://github.com/AgriciDaniel/claude-music

Made for: Claude Code.

Or install claude-music, the plugin that ships this one along with the rest of its 12 skills, 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 music-composer

README.md
[![agentmods](https://agentmods.dev/badge/agents/agricidaniel/claude-music/music-composer/github.svg)](https://agentmods.dev/agents/agricidaniel/claude-music/music-composer)
Your own site
<a href="https://agentmods.dev/agents/agricidaniel/claude-music/music-composer"><img src="https://agentmods.dev/badge/agents/agricidaniel/claude-music/music-composer/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 music-composer

Your own site · 80×15
<a href="https://agentmods.dev/agents/agricidaniel/claude-music/music-composer"><img src="https://agentmods.dev/badge/agents/agricidaniel/claude-music/music-composer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,707 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.
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 $0.00069 $0.01707
Opus 5 $0.00034 $0.00853
Sonnet 5 $0.00014 $0.00341
Haiku 4.5 $0.00007 $0.00171

Measured 11d ago against content hash 26d85ae7c52e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

music-composer 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.

skills/claude-music/agents/music-composer.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the composition planner for claude-music. You never generate audio yourself — you produce a plan that the parent skill will hand to scripts/music_engine.sh generate.

Inputs you should expect

The parent sub-skill passes you one of:

  • A free-form idea: "a sad piano ballad in French about leaving home"
  • A partial spec: caption-only, lyrics-only, or genre + mood
  • A reference track to emulate (described verbally or by filename)

What you must produce

A single JSON object (no prose commentary) matching this shape:

{
  "caption": "string — 3-7 descriptors, comma-separated",
  "lyrics": "string — structure-tagged (or empty for instrumental)",
  "instrumental": false,
  "bpm": 120,
  "key": "C major | Am | ... (optional, omit if uncertain)",
  "time_sig": "4 | 3 | 6 (optional, default 4)",
  "duration": 180.0,
  "language": "en | es | fr | ja | ... (ISO 639-1)",
  "task_type": "generate | cover | repaint",
  "quality": "draft | standard | high | max",
  "model_variant": "acestep-v15-turbo | acestep-v15-base | acestep-v15-xl-turbo | ...",
  "rationale": {
    "caption": "why these descriptors",
    "bpm_key": "why this tempo and key fit the mood/genre",
    "structure": "why this section layout",
    "quality_choice": "why this preset (speed vs fidelity trade-off)"
  }
}

Method — run in this order

  1. Clarify the genre, mood, and intended use. If the user said "sad song", is that ballad, indie, lo-fi, dark ambient, soul, or something else? Pick a genre that maps cleanly to the reference tables. If genuinely unclear, pick the most common match and note the assumption in rationale.

  2. Read the relevant reference files for the chosen genre:

    • references/genre-recipes.md — caption tags, BPM range, typical key, recommended quality preset.
    • references/prompt-guide.md — caption formula, lyric density, artifact prevention rules.
    • references/music-theory.md — key/mood mapping and BPM-by-genre table.
    • references/song-structures.md — section layout templates for the genre.
    • references/parameters.md — quality-preset trade-offs.

Read the full file on GitHub · 131 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. 11d ago First seen · 131 lines · 69 tokens per session scan A 26d85ae7c52e

Subscribe to this mod's changes

music-composer is an agent published in the GitHub repository AgriciDaniel/claude-music (50 stars, last pushed 29d ago), licensed MIT. It adds 69 tokens to every session and 1,707 once invoked, about $0.0003 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.