ACE-Step Music Generation Skill

Use ACE-Step V1.5 API for music generation. Always use scripts/acestep.sh script — do NOT call API endpoints directly.

Quick Start

# 1. cd to this skill's directory
cd {project_root}/{.claude or .codex}/skills/acestep/

# 2. Check API service health
./scripts/acestep.sh health

# 3. Generate with lyrics (recommended)
./scripts/acestep.sh generate -c "pop, female vocal, piano" -l "[Verse] Your lyrics here..." --duration 120 --language zh

# 4. Output saved to: {project_root}/acestep_output/

Workflow

For user requests requiring vocals:

1. Use the acestep-songwriting skill for lyrics writing, caption creation, duration/BPM/key selection
2. Write complete, well-structured lyrics yourself based on the songwriting guide
3. Generate using Caption mode with -c and -l parameters

Only use Simple/Random mode (-d or random) for quick inspiration or instrumental exploration.

If the user needs a simple music video, use the acestep-simplemv skill to render one with waveform visualization and synced lyrics.

MV Production Requirements: Making a simple MV requires three additional skills to be installed:

• acestep-songwriting — for writing lyrics and planning song structure
• acestep-lyrics-transcription — for transcribing audio to timestamped lyrics (LRC)
• acestep-simplemv — for rendering the final music video
• acestep-thumbnail (optional) — for generating cover art / MV background images via Gemini API

MV Background Image: When the user requests MV production, ask whether they want a background image for the video:

1. Generate via Gemini — use the acestep-thumbnail skill (requires Gemini API key configuration)
2. Provide an existing image — user supplies a local image path
3. Skip — use the default animated gradient background (no image needed)

Use AskUserQuestion to let the user choose before proceeding with MV rendering.

Parallel Processing: Lyrics transcription and thumbnail generation are independent tasks. When the user chooses to generate a background image, run acestep-lyrics-transcription and acestep-thumbnail in parallel (e.g. via two concurrent Agent calls) to save time, then use both outputs for the final MV render.

Script Commands

CRITICAL - Complete Lyrics Input: When providing lyrics via the -l parameter, you MUST pass ALL lyrics content WITHOUT any omission:

• If user provides lyrics, pass the ENTIRE text they give you
• If you generate lyrics yourself, pass the COMPLETE lyrics you created
• NEVER truncate, shorten, or pass only partial lyrics
• Missing lyrics will result in incomplete or incoherent songs

Music Parameters: Use the acestep-songwriting skill for guidance on duration, BPM, key scale, and time signature.

# need to cd to this skill's directory first
cd {project_root}/{.claude or .codex}/skills/acestep/

# Caption mode - RECOMMENDED: Write lyrics first, then generate
./scripts/acestep.sh generate -c "Electronic pop, energetic synths" -l "[Verse] Your complete lyrics
[Chorus] Full chorus here..." --duration 120 --bpm 128

# Instrumental only
./scripts/acestep.sh generate "Jazz with saxophone"

# Quick exploration (Simple/Random mode)
./scripts/acestep.sh generate -d "A cheerful song about spring"
./scripts/acestep.sh random

# Cover / Repainting from source audio
./scripts/acestep.sh cover song.mp3 -c "Rock cover style" -l "[Verse] Lyrics..." --duration 120 --bpm 128
./scripts/acestep.sh generate --src-audio song.mp3 --task-type repaint -c "Pop" --repaint-start 30 --repaint-end 60

# Music attribute options
./scripts/acestep.sh generate "Rock" --duration 60 --bpm 120 --key-scale "C major" --time-sig "4/4"
./scripts/acestep.sh generate "Rock" --duration 60 --batch 2
./scripts/acestep.sh generate "EDM" --no-thinking    # Faster

# Other commands
./scripts/acestep.sh status <job_id>
./scripts/acestep.sh health
./scripts/acestep.sh models

Cover / Audio Repainting

The cover command generates music based on a source audio file. The audio is base64-encoded and sent to the API.

# Cover: regenerate with new style/lyrics, preserving melody structure
./scripts/acestep.sh cover input.mp3 -c "Jazz cover" -l "[Verse] New lyrics..." --duration 120

# Repainting: modify a specific region of the audio
./scripts/acestep.sh generate --src-audio input.mp3 --task-type repaint -c "Pop ballad" --repaint-start 30 --repaint-end 90

# Cover options
#   --src-audio         Source audio file path
#   --task-type         cover (default with --src-audio), repaint, text2music
#   --cover-strength    0.0-1.0 (default: 1.0, higher = closer to source)
#   --repaint-start     Repainting start position (seconds)
#   --repaint-end       Repainting end position (seconds)
#   --key-scale         Musical key (e.g. "E minor")
#   --time-signature    Time signature (e.g. "4/4")

Note: For cloud API usage, large audio files may be rejected by Cloudflare. Compress audio before uploading if needed (e.g. using ffmpeg: ffmpeg -i input.mp3 -b:a 64k -ar 24000 -ac 1 compressed.mp3).

Output Files

After generation, the script automatically saves results to the acestep_output folder in the project root (same level as .claude):

project_root/
├── .claude/
│   └── skills/acestep/...
├── acestep_output/          # Output directory
│   ├── <job_id>.json         # Complete task result (JSON)
│   ├── <job_id>_1.mp3        # First audio file
│   ├── <job_id>_2.mp3        # Second audio file (if batch_size > 1)
│   └── ...
└── ...

JSON Result Structure

Important: When LM enhancement is enabled (use_format=true), the final synthesized content may differ from your input. Check the JSON file for actual values:

Field	Description
prompt	Actual caption used for synthesis (may be LM-enhanced)
lyrics	Actual lyrics used for synthesis (may be LM-enhanced)
metas.prompt	Original input caption
metas.lyrics	Original input lyrics
metas.bpm	BPM used
metas.keyscale	Key scale used
metas.duration	Duration in seconds
generation_info	Detailed timing and model info
seed_value	Seeds used (for reproducibility)
lm_model	LM model name
dit_model	DiT model name

To get the actual synthesized lyrics, parse the JSON and read the top-level lyrics field, not metas.lyrics.

Configuration

Important: Configuration follows this priority (high to low):

1. Command line arguments > config.json defaults
2. User-specified parameters temporarily override defaults but do not modify config.json
3. Only config --set command permanently modifies config.json

Default Config File (scripts/config.json)

{
  "api_url": "http://127.0.0.1:8001",
  "api_key": "",
  "api_mode": "completion",
  "generation": {
    "thinking": true,
    "use_format": false,
    "use_cot_caption": true,
    "use_cot_language": false,
    "batch_size": 1,
    "audio_format": "mp3",
    "vocal_language": "en"
  }
}

Option	Default	Description
api_url	http://127.0.0.1:8001	API server address
api_key	""	API authentication key (optional)
api_mode	completion	API mode: completion (OpenRouter, default) or native (polling)
generation.thinking	true	Enable 5Hz LM (higher quality, slower)
generation.audio_format	mp3	Output format (mp3/wav/flac)
generation.vocal_language	en	Vocal language

Prerequisites - ACE-Step API Service

IMPORTANT: This skill requires the ACE-Step API server to be running.

Required Dependencies

The scripts/acestep.sh script requires: curl and jq.

# Check dependencies
curl --version
jq --version

If jq is not installed, the script will attempt to install it automatically. If automatic installation fails:

• Windows: choco install jq or download from https://jqlang.github.io/jq/download/
• macOS: brew install jq
• Linux: sudo apt-get install jq (Debian/Ubuntu) or sudo dnf install jq (Fedora)

Before First Use

You MUST check the API key and URL status before proceeding. Run:

cd "{project_root}/{.claude or .codex}/skills/acestep/" && bash ./scripts/acestep.sh config --check-key
cd "{project_root}/{.claude or .codex}/skills/acestep/" && bash ./scripts/acestep.sh config --get api_url

Case 1: Using Official Cloud API (https://api.acemusic.ai) without API key

If api_url is https://api.acemusic.ai and api_key is empty, you MUST stop and guide the user to configure their key:

1. Tell the user: "You're using the ACE-Step official cloud API, but no API key is configured. An API key is required to use this service."
2. Explain how to get a key: API keys are currently available through acemusic.ai for free.
3. Use AskUserQuestion to ask the user to provide their API key.
4. Once provided, configure it:

   cd "{project_root}/{.claude or .codex}/skills/acestep/" && bash ./scripts/acestep.sh config --set api_key <KEY>
   

5. Additionally, inform the user: "If you also want to render music videos (MV), it's recommended to configure a lyrics transcription API key as well (OpenAI Whisper or ElevenLabs Scribe), so that lyrics can be automatically transcribed with accurate timestamps. You can configure it later via the acestep-lyrics-transcription skill."

Case 2: API key is configured

Verify the API endpoint: ./scripts/acestep.sh health and proceed with music generation.

Case 3: Using local/custom API without key

Local services (http://127.0.0.1:*) typically don't require a key. Verify with ./scripts/acestep.sh health and proceed.

If health check fails:

• Ask: "Do you have ACE-Step installed?"
• If installed but not running: Use the acestep-docs skill to help them start the service
• If not installed: Use acestep-docs skill to guide through installation

Service Configuration

Official Cloud API: ACE-Step provides an official API endpoint at https://api.acemusic.ai. To use it:

./scripts/acestep.sh config --set api_url "https://api.acemusic.ai"
./scripts/acestep.sh config --set api_key "your-key"
./scripts/acestep.sh config --set api_mode completion

API keys are currently available through acemusic.ai for free.

Local Service (Default): No configuration needed — connects to http://127.0.0.1:8001.

Custom Remote Service: Update scripts/config.json or use:

./scripts/acestep.sh config --set api_url "http://remote-server:8001"
./scripts/acestep.sh config --set api_key "your-key"

API Key Handling: When checking whether an API key is configured, use config --check-key which only reports configured or empty without printing the actual key. NEVER use config --get api_key or read config.json directly — these would expose the user's API key. The config --list command is safe — it automatically masks API keys as *** in output.

API Mode

The skill supports two API modes. Switch via api_mode in scripts/config.json:

Mode	Endpoint	Description
completion (default)	/v1/chat/completions	OpenRouter-compatible, sync request, audio returned as base64
native	/release_task + /query_result	Async polling mode, supports all parameters

Switch mode:

./scripts/acestep.sh config --set api_mode completion
./scripts/acestep.sh config --set api_mode native

Completion mode notes:

• No polling needed — single request returns result directly
• Audio is base64-encoded inline in the response (auto-decoded and saved)
• inference_steps, infer_method, shift are not configurable (server defaults)
• --no-wait and status commands are not applicable in completion mode
• Requires model field — auto-detected from /v1/models if not specified

Using acestep-docs Skill for Setup Help

IMPORTANT: For installation and startup, always use the acestep-docs skill to get complete and accurate guidance.

DO NOT provide simplified startup commands - each user's environment may be different. Always guide them to use acestep-docs for proper setup.

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For API debugging, see API Reference.