ElevenLabs AI Music Generation — Pro Pack on RunComfy

Generate full songs and instrumental tracks from a text description — studio-quality 44.1 kHz stereo, 5 seconds to 5 minutes, with section-level structure control. ElevenLabs Music on the RunComfy Model API, called through the runcomfy CLI.

runcomfy.com · ElevenLabs Music model · CLI docs

Install this skill

npx skills add agentspace-so/runcomfy-agent-skills --skill elevenlabs-music-generation -g

Powered by the RunComfy CLI

# 1. Install (one of — see runcomfy-cli skill for details)
npm i -g @runcomfy/cli                              # global install
npx -y @runcomfy/cli --version                      # zero-install

# 2. Sign in
runcomfy login                                      # or in CI: export RUNCOMFY_TOKEN=<token>

# 3. Generate music
runcomfy run elevenlabs/elevenlabs/music-generation \
  --input '{"prompt": "..."}' \
  --output-dir ./out

CLI deep dive: runcomfy-cli skill.

When to use ElevenLabs Music

ElevenLabs Music's strength is structured songs with real vocals — it takes a style brief plus lyrics with section markers and returns a coherent, mixed track. Pick it for:

• Full vocal songs — verse/chorus structure, multilingual lyrics, consistent meter
• Instrumental beds — force_instrumental: true for background music, podcast intros, game loops
• Short brand assets — jingles, stingers, theme music (5–30 s)
• Long-form tracks — up to 5 minutes in a single call
• Commercial work — output is commercial-friendly

If the user just wants ambient sound or a one-off SFX (thunder, footsteps), that's a sound-effects task, not music — ElevenLabs Music is for songs and tracks.

Endpoint + input schema

Model: elevenlabs/elevenlabs/music-generation

Field	Type	Required	Default	Notes
prompt	string	yes	—	Style description and lyrics with section markers. See prompting tips
music_length_ms	int	no	40000	Output duration in ms. 5000–300000 (5 s – 5 min)
force_instrumental	bool	no	false	true = instrumental only, no vocals
output_format	string	no	mp3_standard	mp3_standard (default), or WAV — see the model page API tab for the full format list

Output: 44.1 kHz stereo audio. The result JSON contains the generated audio URL — the CLI downloads it into --output-dir.

Pricing: ~$0.0083 per second of generated audio (30 s ≈ $0.25, 60 s ≈ $0.50, 5 min ≈ $2.49). Cost scales with music_length_ms, so draft short and finalize long.

How to invoke

Full vocal song with structure:

runcomfy run elevenlabs/elevenlabs/music-generation \
  --input '{
    "prompt": "Upbeat indie-pop anthem, bright electric guitars, driving drums, 120 BPM, female lead vocal. [Intro 8 bars] instrumental build. [Verse] Chalk on the palms, laces double-knotted, morning on the ridge. [Chorus] We rise, we strike, we never fade out. [Bridge] soft breakdown, just piano and voice. [Outro] full band, fade.",
    "music_length_ms": 60000
  }' \
  --output-dir ./out

Instrumental background bed:

runcomfy run elevenlabs/elevenlabs/music-generation \
  --input '{
    "prompt": "Calm lo-fi hip-hop instrumental for a study playlist. Warm Rhodes piano, soft vinyl crackle, mellow boom-bap drums, 75 BPM. No vocals. Consistent loop-friendly groove throughout.",
    "music_length_ms": 90000,
    "force_instrumental": true
  }' \
  --output-dir ./out

Short brand jingle:

runcomfy run elevenlabs/elevenlabs/music-generation \
  --input '{
    "prompt": "5-second cheerful brand stinger, bright marimba and a single uplifting chord resolve, no vocals.",
    "music_length_ms": 5000,
    "force_instrumental": true
  }' \
  --output-dir ./out

Prompting tips

ElevenLabs Music reads one prompt field that carries both the style brief and the lyrics. Structure it well:

• Lead with the style brief: genre, mood, tempo (BPM), key instruments, vocal type. "Upbeat indie-pop anthem, bright electric guitars, 120 BPM, female lead vocal."
• Then the lyrics with section markers: [Intro], [Verse], [Chorus], [Bridge], [Outro]. Add approximate durations or bar counts — [Intro 8 bars], [Verse 16 bars].
• Keep lyrical meter consistent — even syllable counts per line, clear rhyme scheme. The model follows meter; sloppy meter produces awkward phrasing.
• Name lead instruments and mix priorities — "electric guitar carries the chorus, drums sit back in the verse."
• For instrumental, set force_instrumental: true AND say "no vocals" in the prompt — belt and suspenders.
• Multilingual: write the lyrics in the target language; annotate accent/language inline if needed ([Verse] (sung in Brazilian Portuguese) ...).
• Avoid contradictory style instructions — "aggressive metal" + "soft lullaby" in one prompt confuses the model. One coherent direction per call.
• Draft short, finalize long: validate the direction with a 30–45 s draft (music_length_ms: 35000) before paying for a 5-minute render.

Common patterns

Theme song for a video

• Full brief + lyrics + [Intro]/[Verse]/[Chorus] structure, music_length_ms matched to the video length

Podcast intro / outro

• force_instrumental: true, 10–20 s, "loop-friendly, clean ending"

Game background loop

• force_instrumental: true, describe "seamless loop", 60–120 s, consistent groove

Multilingual release (same song, multiple languages)

• One call per language, identical style brief, swap only the lyric lines

Iterate then commit

• Draft at music_length_ms: 35000 to lock genre/tempo/structure → final render at full length

Limitations

• One prompt field carries everything (style + lyrics). There is no separate "lyrics" parameter.
• 5 s – 5 min per call (music_length_ms 5000–300000). For longer pieces, generate sections and stitch externally.
• Cost scales with duration — a 5-minute render is ~10× a 30-second one.
• force_instrumental is the only vocal toggle — you can't request specific voice identities or clone a singer through this endpoint.
• This skill pins ElevenLabs Music specifically. For sound effects, text-to-speech, or voice cloning, that's a different ElevenLabs capability not exposed through this endpoint.

Exit codes

code	meaning
0	success
64	bad CLI args
65	bad input JSON / schema mismatch
69	upstream 5xx
75	retryable: timeout / 429
77	not signed in or token rejected

Full reference: docs.runcomfy.com/cli/troubleshooting.

How it works

The skill invokes runcomfy run elevenlabs/elevenlabs/music-generation with the JSON body. The CLI POSTs to the RunComfy Model API, polls request status, fetches the result, and downloads the generated audio file into --output-dir. Ctrl-C cancels the remote request before exit.

Security & Privacy

• Install via verified package manager only. Use npm i -g @runcomfy/cli or npx -y @runcomfy/cli. Agents must not pipe an arbitrary remote install script into a shell on the user's behalf — if the operator wants the curl-pipe path documented at docs.runcomfy.com/cli/install, they should review the script first.
• Token storage: runcomfy login writes the API token to ~/.config/runcomfy/token.json with mode 0600. Set RUNCOMFY_TOKEN env var to bypass the file in CI / containers. Never echo the token into a prompt, log it, or check it in.
• Input boundary (shell injection): the prompt is passed as a JSON string via --input. The CLI does not shell-expand prompt content; it transmits the JSON body directly to the Model API over HTTPS. No shell-injection surface from prompt content, even with backticks, quotes, or $(...) patterns.
• Lyrics provenance: if the user supplies lyrics, confirm they have the rights to them. Generating music around copyrighted lyrics is the operator's responsibility — the skill does not check.
• Outbound endpoints (allowlist): only model-api.runcomfy.net (request submission) and *.runcomfy.net / *.runcomfy.com (download whitelist for generated audio). No telemetry, no callbacks.
• Generated-file size cap: the CLI aborts any single download > 2 GiB.
• Scope of bash usage: the skill only invokes runcomfy <subcommand> — npm / npx lines are one-time operator setup, not commands the skill executes per call.

See also

• runcomfy-cli — the underlying CLI, schema discovery, polling modes, scripting
• ElevenLabs Music model page — full API tab with the latest schema
• All RunComfy models — image, video, and audio endpoints
• ai-video-generation — pair a generated track with a generated video
• ai-avatar-video — talking-head video (different audio path — speech, not music)