# Music Track > Use when generating a looped or cinematic music track. Loops are authored at >=30s with a marked loop point; cinematic tracks at >=60s linear. Trigger on "generate music", "make a calm track", "boss music", "title screen music", "main theme", "exploration loop", "combat track". - **Type:** Skill - **Install:** `agentstack add skill-summerengine-summer-engine-agent-music-track` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [SummerEngine](https://agentstack.voostack.com/s/summerengine) - **Installs:** 0 - **Category:** [Productivity](https://agentstack.voostack.com/c/productivity) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [SummerEngine](https://github.com/SummerEngine) - **Source:** https://github.com/SummerEngine/summer-engine-agent/tree/main/skills/audio/music-track - **Website:** https://summerengine.com/ ## Install ```sh agentstack add skill-summerengine-summer-engine-agent-music-track ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # /music-track — Generate a Loop or Cinematic Music Track ## Overview ElevenLabs Music renders 10–300 seconds of music from a prompt. The output quality depends entirely on prompt specificity: tempo (BPM), key, instrumentation, mood, structural cue. "Epic orchestral" returns generic stock music. "85 BPM, D minor, solo cello and detuned upright piano, sparse, melancholic, no drums, 4/4" returns a usable score for a melancholic exploration scene. This skill produces one track aligned with the audio bible's music style and dynamic music plan, then wires it as an `AudioStreamPlayer` on the `Music` bus with a marked loop point if it's a loop, or as a linear cinematic stream if it's a one-shot. ## When to use - Looped track for a level, biome, menu, or game state (calm / tension / combat). - Cinematic linear track for an intro, ending, boss reveal, or cutscene. - Replacing a placeholder loop with on-bible music. ## When NOT to use - Short stings / event punctuation ( No `.summer/audio-bible.md`. Music without an audio bible drifts into stock-library territory. Run `/audio-direction` first, or I can ship a one-off with explicit defaults — your call. ### 2. Identify the track's role Ask if not obvious: > Which slot in the dynamic music plan? Calm exploration, tension, combat, boss, victory, menu, ending, or one-off cutscene? Each slot has different rules: | Slot | Tempo | Energy | Instrumentation density | Loop or linear | |---|---|---|---|---| | Calm exploration | bible low end (e.g. 70–90) | Low | Sparse | Loop, ≥45s | | Tension | mid (e.g. 90–110) | Medium, no drums or sparse pulse | Adds one instrument | Loop, ≥45s | | Combat | high (e.g. 120–150) | High, full drums | Full | Loop, ≥45s | | Boss | high or low-and-menacing | Distinct from combat | Distinct, named instrument | Loop, ≥60s | | Victory sting | n/a | Resolution | n/a | Linear, 4–8s (use SFX skill instead) | | Menu / title | bible mid | Atmospheric | Anchor instrument | Loop, ≥30s | | Cutscene | varies | Linear arc | Varies | Linear, 60–180s | | Ending | varies | Linear arc with resolution | Varies | Linear, 60–300s | ### 3. Build the prompt — tempo + key + instrumentation + mood + structural cue Prompts that work: ``` 85 BPM, D minor, 4/4, solo cello and detuned upright piano, sparse, melancholic exploration loop, no drums, gentle reverb, even dynamics, 60s 128 BPM, D dorian, 4/4, full orchestral combat, low brass ostinato, taiko drums on 1 and 3, strings tremolo, urgent, no melodic resolution, 60s loop 90 BPM, A minor, 6/8, lo-fi exploration, vintage Rhodes electric piano, tape hiss, warm bass, soft brushed snare, no vocals, 45s loop 70 BPM, F minor, 4/4, ambient menu loop, pad layer, distant choir, single piano motif every 8 bars, no drums, 30s loop with seamless return 110 BPM, C minor harmonic, 4/4, dark synthwave boss intro, gated reverb snare, arpeggiated bass synth, lead saw on melody, builds to cymbal swell at 0:50, linear 60s, ends on sustained pad ``` Prompts that DON'T work (and why): | Bad prompt | Failure mode | |---|---| | `epic orchestral combat music` | No tempo, no key, no instrumentation. Generic stock. | | `Hollow Knight style track` | The model can't reference IPs and won't try to clone style words. | | `hopeful but sad menu music with strings and stuff` | "Strings and stuff" is vague; model picks the wrong section. | | `something for the boss fight` | No tempo, no key, no mood vector. Random. | | `loop` (just the word) | No structure. Returns 30s of music that doesn't loop. | ### 4. Tempo, key, instrumentation specifics that matter **Tempo (BPM)** — name a single number, not a range. Music model interprets ranges as mid-point with drift. `85 BPM` is better than `80–90 BPM`. **Key** — name mode (`D minor`, `D dorian`, `D natural minor`, `C minor harmonic`). The bible's modulation rules go here: combat tracks shift to dorian, calm tracks to natural minor. **Instrumentation** — name 2–4 specific instruments, not sections. `solo cello` not `strings`. `upright piano` not `keys`. `Rhodes electric piano` not `electric piano`. The model's vocabulary is closer to a session musician's than a producer's. **Mood** — concrete adjectives anchored to motion: `melancholic and slow`, `urgent and driving`, `triumphant and rising`. Avoid genre adjectives like `epic`, `chill`, `hype`. **Structural cue** — for linear tracks, name the arc: `builds at 0:30 to a hit at 0:50, decays`. For loops, name the cell: `4-bar phrase repeats, instrument swap every 8 bars`. ### 5. Loop vs cinematic decision | Choose loop when | Choose linear when | |---|---| | The slot plays for an unbounded time (level, menu, exploration) | The slot has a known length (cutscene, intro, ending) | | Player attention is on gameplay | Player attention is on the music | | You want to layer adaptive stems on top later | The arc is the point | For loops: generate **≥30s, prefer 45–60s**. Shorter loops are recognized as repetition within 90s of play and become annoying. The bible's "no state stays >90s without variation" rule means even a 60s loop should contain internal variation (instrument swap on alternating cycles). For linear: generate **≥60s for cutscenes, up to 300s for endings**. The model handles long arcs better than people expect; ask for one rendered piece rather than splicing. ### 6. Confirm and call Show the prompt: > Prompt: > `85 BPM, D minor, 4/4, solo cello and detuned upright piano, sparse, melancholic exploration loop, no drums, gentle reverb, 60s loop` > Duration 60s. Cost: ~12 credits. Generate? ``` summer_generate_audio( capability: "music", prompt: "85 BPM, D minor, 4/4, solo cello and detuned upright piano, sparse, melancholic exploration loop, no drums, gentle reverb, 60s loop", durationSeconds: 60 ) // Result: { asset: { fileUrl, ... } } // Then: summer_import_from_url(url: "", path: "res://audio/music/calm_exploration.mp3") ``` `durationSeconds` range is 10–300. ### 7. Mark the loop point in Godot ElevenLabs Music does not return a loop-clean cut. You must mark the loop point in Godot's import dock so playback returns to the loop point on completion, not to 0:00. In `audio/music/calm_exploration.mp3.import`: ``` [params] loop = true loop_offset = 0.0 loop_mode = 0 # 0=disabled, 1=forward, 2=ping-pong, 3=backward ``` If the start has a fade-in but the body is loopable, set `loop_offset = 4.0` (4 seconds of intro skipped on loop, plays full track first time). For seamless looping, the cleaner option is to ask the model to generate a cell (one bar / one phrase) and concatenate; or generate at 60s and trust the model's structural cue. Crossfade looping in code is the practical fallback (see step 9). ### 8. Wire it as `AudioStreamPlayer` on the `Music` bus ``` summer_add_node(parentPath="/root/Game", type="AudioStreamPlayer", name="MusicCalm") summer_set_prop(path="/root/Game/MusicCalm", property="stream", value="res://audio/music/calm_exploration.mp3") summer_set_prop(path="/root/Game/MusicCalm", property="bus", value="Music") summer_set_prop(path="/root/Game/MusicCalm", property="volume_db", value=-8.0) summer_set_prop(path="/root/Game/MusicCalm", property="autoplay", value=true) ``` Music is `AudioStreamPlayer` (not 2D / 3D) — non-positional. The bible's `Music -8 dB` mix sits the music behind SFX where it belongs. ### 9. Crossfade-loop pattern (no marked loop point) If the loop click bothers the user, use a two-player crossfade: ```gdscript # scripts/audio/MusicLoopCrossfade.gd extends Node @export var stream: AudioStream @export var fade: float = 1.0 var _a: AudioStreamPlayer var _b: AudioStreamPlayer var _active: AudioStreamPlayer func _ready() -> void: _a = _make_player() _b = _make_player() _active = _a _active.play() _active.finished.connect(_on_finished) func _make_player() -> AudioStreamPlayer: var p := AudioStreamPlayer.new() p.stream = stream p.bus = "Music" p.volume_db = -8.0 add_child(p) return p func _on_finished() -> void: var next := _b if _active == _a else _a next.play() next.finished.connect(_on_finished, CONNECT_ONE_SHOT) _active = next ``` The next instance starts at 0:00 the moment the previous finishes — gapless. ## Reference card — prompts by slot ``` Calm explore (folk): 78 BPM, D minor, 6/8, fingerpicked acoustic guitar, upright bass on 1, soft hand percussion, no melody on first 8 bars, 60s loop Tension (orchestral): 95 BPM, D dorian, 4/4, low strings sustained, single timpani roll every 8 bars, sparse french horn motif, no drums, 60s loop Combat (orchestral): 140 BPM, D dorian, 4/4, taiko drums on 1 and 3, ostinato low brass, strings tremolo, urgent and driving, no melodic resolution, 60s loop Boss (synthwave): 110 BPM, C minor harmonic, 4/4, gated snare, arpeggio bass synth, lead saw on melody, builds at 0:50, linear 60s Menu (lo-fi): 70 BPM, F minor, 4/4, vintage Rhodes, tape hiss, soft brushed snare, single piano motif every 8 bars, 45s loop Cutscene (cinematic): varies tempo, D minor, 4/4, solo piano opens, strings enter at 0:20, full orchestra at 0:50, decay to solo piano at 1:30, linear 120s ``` ## Anti-patterns - **Genre adjectives only.** `epic`, `chill`, `hype` — meaningless. - **Naming a game or composer.** Model won't replicate; use ingredients. - **Loop shorter than 30s.** Recognized as repetition fast. - **Music on `Master` bus at 0 dB.** Buries SFX. Use `Music` bus at `-8 dB`. - **Generating before reading the bible.** Style drift. - **Skipping the loop-mark step.** Music returns to 0:00 with a click on every loop. ## Edge cases - **Clip is 50s but you wanted 60s.** Either regenerate (cheaper than you think) or extend by overlap-crossfading the last 5s onto the start in an audio editor. - **Loop click on every cycle.** Use the crossfade pattern in step 9. - **Clip is too long.** Trim the tail in the import dock with `loop_offset`, or in an audio editor. - **Track sounds nothing like the references.** Re-read the bible; the prompt may be missing the anchor instrument. Add it explicitly. - **Track has unexpected vocals.** Add `no vocals, instrumental only` to the prompt. ## Fallback (no MCP) Print the prompt and instruct the user to run via the Summer dashboard, then `summer_import_from_url` the rendered MP3. ## Handoff > Track `calm_exploration.mp3` wired to `Game/MusicCalm` on the `Music` bus, autoplay on. Next: > - Mark the loop point in the import dock if the bible calls for looped playback. > - Generate the tension and combat counterparts with `/music-track` again. > - To wire state-driven crossfades between calm / tension / combat, run `/adaptive-music`. ## See also - `audio/audio-direction` — defines style, tempo, key, model - `audio/adaptive-music` — wiring stems to game state - `audio/sound-effect` — short stings - `audio/ambient-bed` — non-melodic location bed ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [SummerEngine](https://github.com/SummerEngine) - **Source:** [SummerEngine/summer-engine-agent](https://github.com/SummerEngine/summer-engine-agent) - **License:** MIT - **Homepage:** https://summerengine.com/ Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-summerengine-summer-engine-agent-music-track - Seller: https://agentstack.voostack.com/s/summerengine - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. 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