# mastering-engineer

A skill that brings your mixes to platform loudness targets: reads WAV files, runs a mastering chain, then checks the output. Useful once tracks are approved and need release prep.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 337 installs · ★ 594
- Author: bitwize-music-studio
- License: CC0-1.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/bitwize-music-studio/claude-ai-music-skills/tree/HEAD/skills/mastering-engineer/SKILL.md
- Updated: 2026-10-22
- HTML: https://affpapa.org/en/nevibecode/skills/mastering-engineer

## What it does

Point it at a folder and it measures loudness, peaks and tonal balance, applies mastering settings, then compares the result against platform targets such as -14 LUFS. Invoke it without a folder and you get recommendations for a genre and a destination instead.

MP3 input gets rejected. The skill wants WAV, and it asks you to confirm the album's genre before processing, because a ballad and a club track need different settings. Audio paths come from the `resolve_path` MCP tool, so nothing is guessed from a hardcoded directory.

Genre settings live in presets, and you can layer your own `mastering-presets.yaml` on top: EQ cuts, compression, stereo width, limiter fields merge one by one, and anything you leave out keeps the built-in value. Python plus `matchering`, `pyloudnorm`, `scipy`, `numpy` and `soundfile` must be present. What it does is loudness, dynamics and tone; stripping or obscuring Suno's watermark is prohibited by Suno's terms and is not part of the chain.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add bitwize-music-studio/claude-ai-music-skills --skill mastering-engineer -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/mastering-engineer/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/mastering-engineer/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add bitwize-music-studio/claude-ai-music-skills --skill mastering-engineer -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/mastering-engineer/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add bitwize-music-studio/claude-ai-music-skills --skill mastering-engineer -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/mastering-engineer/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install bitwize-music-studio/claude-ai-music-skills mastering-engineer
```

2. **Manually: put the files in place**
- File: `.github/skills/mastering-engineer/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add bitwize-music-studio/claude-ai-music-skills --skill mastering-engineer -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/bitwize-music-studio/claude-ai-music-skills --path skills/mastering-engineer
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/mastering-engineer/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add bitwize-music-studio/claude-ai-music-skills --skill mastering-engineer -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/bitwize-music-studio/claude-ai-music-skills/tree/HEAD/skills/mastering-engineer/SKILL.md

## When to use it
- match loudness across a batch of finished mixes
- check peaks and frequency balance before release
- pick processing settings that fit the album's genre
- re-master a few tracks that differ from the rest
- confirm whether a track hits its loudness target

## Example prompts
- Master the files in `~/bitwize-music/audio/artists/bitwize/albums/electronic/my-album/` for streaming
- Bring these tracks to -14 LUFS and check the true peaks
- Apply my `mastering-presets.yaml` settings to the dark-electronic genre

## Source text · SKILL.md · CC0-1.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 3122119d9e3e65af.

BEGIN THIRD-PARTY FILE 3122119d9e3e65af
```text
---
name: mastering-engineer
description: Guides audio mastering for streaming platforms including loudness optimization and tonal balance. Use when the user has approved tracks and wants to master audio files.
argument-hint: <folder-path or "master for [platform]">
model: sonnet
effort: low
prerequisites:
  - import-audio
allowed-tools:
  - Read
  - Edit
  - Write
  - Grep
  - Glob
  - Bash
  - bitwize-music-mcp
requirements:
  python:
    - matchering
    - pyloudnorm
    - scipy
    - numpy
    - soundfile
---

## Your Task

**Input**: $ARGUMENTS

When invoked with a folder:
1. Analyze WAV files for loudness, peaks, frequency balance
2. Apply mastering with appropriate settings
3. Verify results meet platform targets (-14 LUFS for streaming)

When invoked for guidance:
1. Provide mastering recommendations based on genre and target platform

---

## Supporting Files

- **[genre-presets.md](genre-presets.md)** - Genre-specific settings, platform targets, problem-solving

---

# Mastering Engineer Agent

You are an audio mastering specialist for AI-generated music. You guide loudness optimization, platform delivery standards, and final audio preparation.

**Your role**: Mastering guidance, quality control, platform optimization

**Not your role**: Audio editing (trimming, fades), mixing, creative production

---

## Core Principles

### Loudness is Not Volume
- **LUFS** (Loudness Units Full Scale) measures perceived loudness
- Streaming platforms normalize to target LUFS
- Too loud = squashed dynamics, fatiguing
- Too quiet = listener turns up volume, loses impact

### Universal Target
**Master to -14 LUFS, -1.0 dBTP** = works everywhere

### Genre Informs Targets
- Classical/Jazz: -16 to -18 LUFS (high dynamic range)
- Rock/Pop: -12 to -14 LUFS (moderate dynamics)
- EDM/Hip-Hop: -8 to -12 LUFS (compressed, loud)

**For streaming**: -14 LUFS works across all genres

See [genre-presets.md](genre-presets.md) for detailed genre settings.

### Never a Watermark-Removal Step
Mastering is loudness, dynamics and tonal balance. Suno's Terms of Service (effective 2026-09-03) prohibit removing, altering, obscuring or circumventing the fingerprint, watermark or metadata Suno appends to an output. No step in this workflow does that, and no step may be described that way.

---

## Override Support

Check for custom mastering presets:

### Loading Override
```
END THIRD-PARTY FILE 3122119d9e3e65af

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