Audio

Audio tracks provide background music, sound effects, and ambient sounds. They can be triggered by AI directives, rules, or automatic playlists.

AudioTrack Schema

{
  "id": "bgm-tavern",
  "name": "Tavern Theme",
  "type": "bgm",
  "url": "@asset:uuid-here",
  "loop": true,
  "volume": 0.4,
  "fadeIn": 2,
  "fadeOut": 1.5,
  "maxDuration": null
}

Field	Type	Description
id	string	Unique kebab-case ID
name	string	Display name
type	"bgm" | "sfx" | "ambient"	Track type
url	string	Audio source — @asset:{id} or direct URL
loop	boolean	Whether to loop (typical: true for BGM/ambient, false for SFX)
volume	number	0.0 to 1.0
fadeIn	number | null	Fade-in duration in seconds
fadeOut	number | null	Fade-out duration in seconds
maxDuration	number | null	Auto-stop after N seconds

AI Audio Directives

The AI triggers audio through bracket directives:

[audio: bgm-tavern play]
[audio: sfx-sword play]
[audio: bgm-tavern stop]
[audio: bgm-battle crossfade 2.5]
[audio: ambient-rain volume 0.3]
[audio: sfx-magic play chain:bgm-ambient]

Action	Description
play	Start playing the track
stop	Stop the track
crossfade <seconds>	Crossfade from current BGM to this track
volume <0-1>	Change track volume
play chain:<trackId>	Play this track, then auto-play the next

BGM Playlist

Auto-play a sequence of BGM tracks:

{
  "bgmPlaylist": {
    "tracks": ["bgm-explore-1", "bgm-explore-2", "bgm-explore-3"],
    "playMode": "shuffle",
    "gapSeconds": 0,
    "autoPlay": true,
    "waitForFirstMessage": true
  }
}

Field	Type	Description
tracks	string[]	Array of track IDs to cycle through
playMode	"loop" | "shuffle" | "sequential"	Playback order mode
gapSeconds	number	Silence between tracks (default: 0, max: 30)
autoPlay	boolean	Start playing automatically (default: true)
waitForFirstMessage	boolean	Don't start until the player sends their first message

Conditional BGM

Play specific tracks when conditions are met. Supports variable checks, keyword matching, turn count, and session start triggers.

{
  "conditionalBGM": [
    {
      "id": "combat-music",
      "name": "Combat Music",
      "targetTrackId": "bgm-battle",
      "triggerType": "variable",
      "conditions": [
        { "variableId": "in-combat", "operator": "eq", "value": true }
      ],
      "conditionLogic": "all",
      "priority": 10,
      "fadeInDuration": 1,
      "fadeOutDuration": 2,
      "stopPreviousBGM": true,
      "fallback": "default"
    }
  ]
}

Field	Type	Description
id	string	Unique identifier
name	string	Display name
targetTrackId	string	Track to play when triggered
triggerType	"variable" | "ai-keyword" | "keyword" | "turn-count" | "session-start"	What triggers the conditional BGM
conditions	Condition[]	Variable conditions to check
conditionLogic	"all" | "any"	How multiple conditions combine (default: "all")
keywords	string[]	Keywords to match (for keyword / ai-keyword triggers)
matchWholeWords	boolean	Match whole words only (for keyword triggers)
atTurn	number	Fire at specific turn (for turn-count trigger)
everyNTurns	number	Fire every N turns (for turn-count trigger)
priority	number	Higher priority wins when multiple triggers match
fadeInDuration	number	Fade-in duration in seconds
fadeOutDuration	number	Fade-out duration in seconds
stopPreviousBGM	boolean	Stop the currently playing BGM first
fallback	"default" | "previous" | trackId string	What to play when the condition becomes false

Condition operators use short form: eq, neq, gt, lt, gte, lte, contains.

When the condition becomes true, the track starts. When false, it stops (with fade-out if configured) and falls back according to the fallback setting.