A music tool that turns MIDI or MusicXML—the formats used to store musical notes—into WAV or MP3 audio, or into Strudel live-coding patterns. It can use analysis data about tempo, key, chords, and dynamics.

Use it to render MIDI or MusicXML files, remove ghost notes, and create duration-aware Strudel patterns for live coding.

It removes the need to manually clean unwanted notes or convert notation before rendering or experimenting with music code.

midi-synth — Skill for Claude Code and Codex by maystudios

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.

Any agent

npx skills add maystudios/claude-skills --skill midi-synth

Clone the repo

git clone --depth 1 https://github.com/maystudios/claude-skills

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/maystudios/claude-skills/midi-synth/github.svg)](https://agentmods.dev/skills/maystudios/claude-skills/midi-synth)

Your own site

<a href="https://agentmods.dev/skills/maystudios/claude-skills/midi-synth"><img src="https://agentmods.dev/badge/skills/maystudios/claude-skills/midi-synth/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/maystudios/claude-skills/midi-synth"><img src="https://agentmods.dev/badge/skills/maystudios/claude-skills/midi-synth.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 187 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,272 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.

Model	Per session	Once invoked
Fable 5.1	$0.00187	$0.01272
Opus 5	$0.00093	$0.00636
Sonnet 5	$0.00037	$0.00254
Haiku 4.5	$0.00019	$0.00127

Measured 9d ago against content hash 5e9cfc2488de, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

midi-synth 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 9d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/render.py, scripts/to_strudel.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

midi-synth/SKILL.md · 120 lines

How it starts

The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MIDI Synth

Synthesize MIDI/MusicXML to audio and generate Strudel live-coding patterns. Uses analysis data for ghost-note cleaning, correct tempo, and key-aware filtering.

Scripts

scripts/to_strudel.py -- MIDI/MusicXML to Strudel patterns with duration-aware notation
scripts/render.py -- MIDI/MusicXML to WAV/MP3 with cleaning and modifications

Both scripts auto-detect *_analysis.json files from audio-to-midi for tempo, key, and dynamics.

Workflow

Identify input: MIDI (.mid) or MusicXML (.musicxml)
Auto-detect or specify the analysis JSON from audio-to-midi
Choose workflow:
- Creative: to_strudel.py generates Strudel code for strudel.cc
- Rendering: render.py produces WAV/MP3
- Both: run both on the same input
Ghost notes are automatically cleaned using velocity, duration, and key filters

Strudel Code Generation

# Basic (auto-detects analysis JSON next to input)
py -3.12 scripts/to_strudel.py "song.mid"

# From MusicXML
py -3.12 scripts/to_strudel.py "song.musicxml"

# Explicit analysis file
py -3.12 scripts/to_strudel.py "song.mid" --analysis "song_analysis.json"

# Stricter ghost-note filtering
py -3.12 scripts/to_strudel.py "song.mid" --min-velocity 60 --min-duration 0.1

# Open in browser
py -3.12 scripts/to_strudel.py "song.mid" --open

Flag	Default	Effect
`--analysis`	auto-detect	Path to analysis JSON for tempo/key
`--bars`	4	Pattern length in bars
`--resolution`	16	Grid: 4/8/16/32
`--min-velocity`	40	Remove notes below this velocity (0-127)
`--min-duration`	0.05	Remove notes shorter than this (seconds)
`--no-key-filter`	off	Disable key-based ghost note filtering
`--tempo`	from analysis	Override tempo BPM
`--open`	off	Open in strudel.cc in browser

Note durations are encoded with @N notation (e.g., c3@4 = held for 4 steps).

Audio Rendering

# Basic (auto-detects analysis, cleans ghost notes)
py -3.12 scripts/render.py "song.mid" --mp3

# From MusicXML
py -3.12 scripts/render.py "song.musicxml" --mp3

# With SoundFont
py -3.12 scripts/render.py "song.mid" --soundfont "GeneralUser_GS.sf2" --mp3

# Aggressive cleaning
py -3.12 scripts/render.py "song.mid" --min-velocity 60 --min-duration 0.1

# Skip cleaning entirely
py -3.12 scripts/render.py "song.mid" --no-clean

# Modifications
py -3.12 scripts/render.py "song.mid" --tempo 2.0 --transpose 3 --instrument 0

Read the full file on GitHub · 120 lines

Files

What ships with it

3 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.

9d ago First seen · 120 lines · 187 tokens per session scan A 5e9cfc2488de

Subscribe to this mod's changes

midi-synth is a skill published in the GitHub repository maystudios/claude-skills (22 stars, last pushed 25d ago), licensed MIT. It adds 187 tokens to every session and 1,272 once invoked, about $0.0009 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.

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