minimax-music-gen

# MiniMax Music Generation Skill

Generate songs (vocal or instrumental) using the MiniMax Music API. Supports two creation
modes: **Basic** (one-sentence-in, song-out) and **Advanced Control** (edit lyrics, refine
prompt, plan before generating).

## Prerequisites

- **mmx CLI** (required): Music generation uses the `mmx` command-line tool.

  **Check if installed:**
  ```bash
  command -v mmx && mmx --version || echo "mmx not found"
  ```

  **Install (requires Node.js):**
  ```bash
  npm install -g mmx-cli
  ```

  **Authenticate (first time only):**
  ```bash
  mmx auth login --api-key <your-minimax-api-key>
  ```
  The API key can be obtained from [MiniMax Platform](https://platform.minimaxi.com/).
  Credentials are saved to `~/.mmx/credentials.json` and persist across sessions.

  **Verify:**
  ```bash
  mmx quota show
  ```

- **Audio player** (recommended): `mpv`, `ffplay`, or `afplay` (macOS built-in) for local
  playback. `mpv` is preferred for its interactive controls.

## CLI Tool

This skill uses the `mmx` CLI for all music generation:

- **Music Generation**: `mmx music generate` — model: `music-2.6-free`
  - Supports `--lyrics-optimizer` to auto-generate lyrics from prompt
  - Supports `--instrumental` for instrumental tracks
  - Supports `--lyrics` for user-provided lyrics
  - Structured params: `--genre`, `--mood`, `--vocals`, `--instruments`, `--bpm`, `--key`, `--tempo`, `--structure`, `--references`
  
- **Cover**: `mmx music cover` — model: `music-cover-free`
  - Takes reference audio via `--audio-file <path>` or `--audio <url>`
  - `--prompt` describes the target cover style

**Agent flags**: Always add `--quiet --non-interactive` when calling mmx from agents.

**Pipeline**:
- Vocal: `User description -> mmx music generate --lyrics-optimizer -> MP3`
- Instrumental: `User description -> mmx music generate --instrumental -> MP3`
- Cover: `Source audio + style -> mmx music cover -> MP3`

## Storage

All generated music is saved to `~/Music/minimax-gen/`. Create the directory if it doesn't
exist. Files are named with a timestamp and a short slug derived from the prompt:
`YYYYMMDD_HHMMSS_<slug>.mp3`

---

## Language & Interaction

Detect the user's language from their first message and respond in that language for the
entire session. This applies to all interaction text, questions, confirmations, and feedback
prompts.

**User-facing text localization rule**:
- ALL text shown to the user — including preview labels, field names, confirmations, status
  messages, playback info, feedback prompts, **and the prompt/description preview** — MUST
  be fully translated into the user's language.
- The **API prompt** sent to the model should always be written in English for best
  generation quality. However, when previewing the prompt to the user, show a localized
  description in the user's language instead of the raw English prompt. The English prompt
  is an internal implementation detail — the user does not need to see it.
- The templates below are written in English as reference. At runtime, translate every label
  and message into the user's detected language.

**Lyrics language rule**:
- Default lyrics language = the user's language. A Chinese-speaking user gets Chinese lyrics;
  an English-speaking user gets English lyrics.
- Only generate lyrics in a different language if the user **explicitly** requests it.
- When a different lyrics language is needed, embed it naturally into the vocal or genre
  description in the prompt. For example, instead of appending "with Korean lyrics", use
  "featuring a Korean female vocalist" or specify a genre that implies the language (e.g.,
  "K-pop", "J-rock", "Mandopop", "Latin pop").

---

## Workflow

### Step 0: Detect Intent

Parse the user's message to determine:

1. **Song category**: vocal (with lyrics), instrumental (no vocals), or cover
2. **Creation mode preference**: did they provide detailed requirements (Advanced) or a
   casual one-liner (Basic)?

If ambiguous, ask using this decision tree:

```
Q1: What type of music?
  - Vocal (with lyrics)
  - Instrumental (no vocals)
  - Cover

Q2: Creation mode?
  - Basic — one-line description, auto-generate
  - Advanced — edit lyrics, refine prompt, plan
```

If the user gives a clear one-liner like "make me a sad piano piece", skip the questions —
infer instrumental + basic mode and proceed.

---

### Step 1: Basic Mode

**Goal**: User provides a short description, the skill auto-generates everything, then calls
the API.

1. **Expand the description into a prompt**: Take the user's one-liner and expand it into a
   rich music prompt. Refer to the **Prompt Writing Guide** appendix at the end of this
   document for style vocabulary, genre/instrument references, and prompt structure.
   **The API prompt should always be written in English** for best generation quality,
   regardless of the user's language.
   
   Follow this pattern:
   ```
   A [mood] [BPM optional] [genre] song, featuring [vocal description],
   about [narrative/theme], [atmosphere], [key instruments and production].
   ```

2. **Show the user a preview** before generating. Translate all labels AND the prompt
   description into the user's language. The English prompt is only used internally when
   calling the API — the user should never see it. Example template (English reference —
   localize everything at runtime):

   ```
   About to generate:
   Type: Vocal / Instrumental
   Description: indie folk, melancholy, acoustic guitar, gentle female voice
   Lyrics: Auto-generated (--lyrics-optimizer)
   
   Confirm? (press enter to confirm, or tell me what to change)
   ```

3. **Call mmx**: Generate the music directly.

---

### Step 2: Advanced Control Mode

**Goal**: User has full control over every parameter before generation.

1. **Lyrics phase**:
   - If user provided lyrics: display them formatted with section markers, ask for edits.
     The final lyrics will be passed via `--lyrics` to mmx.
   - If user has a theme but no lyrics: will use `--lyrics-optimizer` to auto-generate.
   - Support iterative editing: "change the second chorus" -> only rewrite that section.
   - User can also write lyrics themselves and pass via `--lyrics`.

2. **Prompt phase**:
   - Generate a recommended prompt based on the lyrics' mood and content.
   - Present it as editable tags the user can add/remove/modify.
   - Refer to the **Prompt Writing Guide** appendix for the full vocabulary.

3. **Advanced planning** (optional, offer but don't force):
   - Song structure: verse-chorus-verse-chorus-bridge-chorus or custom
   - BPM suggestion (encode in prompt as tempo descriptor)
   - Reference style: "something like X style" -> map to prompt tags
   - Vocal character description

4. **Final confirmation**: Show complete parameter summary, then generate.

---

### Step 3: Call mmx

Generate music using the mmx CLI:

**Vocal with auto-generated lyrics:**
```bash
mmx music generate \
  --prompt "<prompt>" \
  --lyrics-optimizer \
  --genre "<genre>" --mood "<mood>" --vocals "<vocal style>" \
  --instruments "<instruments>" --bpm <bpm> \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

**Vocal with user-provided lyrics:**
```bash
mmx music generate \
  --prompt "<prompt>" \
  --lyrics "<lyrics with section markers>" \
  --genre "<genre>" --mood "<mood>" --vocals "<vocal style>" \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

**Instrumental (no vocal):**
```bash
mmx music generate \
  --prompt "<prompt>" \
  --instrumental \
  --genre "<genre>" --mood "<mood>" --instruments "<instruments>" \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

Use structured flags (`--genre`, `--mood`, `--vocals`, `--instruments`, `--bpm`, `--key`,
`--tempo`, `--structure`, `--references`, `--avoid`, `--use-case`) to give the API
fine-grained control instead of cramming everything into `--prompt`.

Display a progress indicator while waiting. Typical generation takes 30-120 seconds.

---

### Step 4: Playback

After generation, detect an available audio player and play the file.

**Detect player:**
```bash
command -v mpv || command -v ffplay || command -v afplay
```

**Play based on detected player (in priority order):**

| Player | Command | Controls |
|--------|---------|----------|
| `mpv` (preferred) | `mpv --no-video ~/Music/minimax-gen/<filename>.mp3` | space = pause/resume, q = quit, left/right = seek |
| `ffplay` | `ffplay -nodisp -autoexit ~/Music/minimax-gen/<filename>.mp3` | q = quit |
| `afplay` (macOS) | `afplay ~/Music/minimax-gen/<filename>.mp3` | Ctrl+C = stop |
| None found | Do not attempt playback | Show file path only |

After starting playback, tell the user (localize all text):

```
Now playing: <filename>.mp3
Saved to: ~/Music/minimax-gen/<filename>.mp3
```

Do NOT show playback controls (e.g. keyboard shortcuts) — they don't work in this
environment since the player runs in the background.

If no player is found (localize all text):

```
No audio player detected.
File saved to: ~/Music/minimax-gen/<filename>.mp3
Tip: Install mpv for the best playback experience (brew install mpv).
```

---

### Step 5: Feedback & Iteration

After playback, ask for feedback:

```
How was this song?
  1. Love it, keep it!
  2. Not quite, adjust and regenerate
  3. Fine-tune lyrics/style then regenerate
  4. Don't want it, start over
```

Based on feedback:
- **Satisfied**: Done. Mention the file path again.
- **Adjust & regenerate**: Ask what to change (prompt? lyrics? style?), apply edits,
  re-run generation. Keep the old file with a `_v1` suffix for comparison.
- **Fine-tune**: Enter Advanced Control Mode with the current parameters pre-filled.
- **Delete & restart**: Remove the file, go back to Step 0.

---

## Cover Mode

Generate a cover version of a song based on reference audio. Model: `music-cover-free`.

**Reference audio requirements**: mp3, wav, flac — duration 6s to 6min, max 50MB.
If no lyrics are provided, the original lyrics are extracted via ASR automatically.

### Workflow

When the user selects Cover mode:
1. Ask for the source audio — a local file path or URL
2. Ask for the target cover style (e.g., "acoustic cover, stripped-down, intimate vocal")
3. Optionally ask for custom lyrics or lyrics file

### Commands

**Cover from local file:**
```bash
mmx music cover \
  --prompt "<cover style description>" \
  --audio-file <source.mp3> \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

**Cover from URL:**
```bash
mmx music cover \
  --prompt "<cover style description>" \
  --audio <source_url> \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

**With custom lyrics (text):**
```bash
mmx music cover \
  --prompt "<style>" \
  --audio-file <source.mp3> \
  --lyrics "<custom lyrics>" \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

**With custom lyrics (file):**
```bash
mmx music cover \
  --prompt "<style>" \
  --audio-file <source.mp3> \
  --lyrics-file <lyrics.txt> \
  --out ~/Music/minimax-gen/<filename>.mp3 \
  --quiet --non-interactive
```

### Optional flags

| Flag | Description |
|------|-------------|
| `--seed <number>` | Random seed 0-1000000 for reproducible results |
| `--channel <n>` | `1` (mono) or `2` (stereo, default) |
| `--format <fmt>` | `mp3` (default), `wav`, `pcm` |
| `--sample-rate <hz>` | Sample rate (default: 44100) |
| `--bitrate <bps>` | Bitrate (default: 256000) |

### After generation
Proceed with normal playback and feedback flow (Step 4 & 5).

---

## Error Handling

| Error | Action |
|-------|--------|
| mmx not found | `npm install -g mmx-cli` |
| mmx auth error (exit code 3) | `mmx auth login` |
| Quota exceeded (exit code 4) | Report quota limit, suggest waiting or upgrading |
| API timeout (exit code 5) | Retry once, then report failure |
| Content filter (exit code 10) | Adjust prompt to avoid filtered content |
| Invalid lyrics format | Auto-fix section markers, warn user |
| No audio player found | Save file and tell user the path, suggest installing mpv |
| Network error | Show error detail, suggest checking connection |

---

## Important Notes

- **Never reproduce copyrighted lyrics.** When doing covers, always write original lyrics
  inspired by the song's theme. Explain this to the user.
- **Prompt language**: The API prompt works best with English tags. Chinese tags are also
  acceptable. Mixing is OK.
- **Section markers in lyrics**: The API recognizes `[verse]`, `[chorus]`, `[bridge]`,
  `[outro]`, `[intro]`. Always include them when providing `--lyrics`.
- **File management**: If `~/Music/minimax-gen/` has more than 50 files, suggest cleanup
  when starting a new session.
- **Structured params**: Prefer using `--genre`, `--mood`, `--vocals`, `--instruments`,
  `--bpm` etc. over embedding everything in `--prompt`. This gives the API better control.
- **Lyrics language via style**: When the user wants lyrics in a specific language, express
  it through the vocal description or genre (e.g., "Japanese female vocalist", "Mandopop
  ballad") rather than appending a language directive to the prompt.

---

## Appendix: Prompt Writing Guide

See [references/prompt_guide.md](references/prompt_guide.md) for the complete prompt writing guide,
including genre/vocal/instrument references and BPM tables.