version: "1.0.0" name: sound-effects description: Produces game sound effects as UE-ready WAV files, either with the bound ElevenLabs sound-effect model or by synthesizing them locally with FFmpeg. Use when the user asks for 音效、做个脚步声、按钮点击声、爆炸声、枪声、拾取金币的声音、风声循环、UI 提示音 or sound variants for randomized playback. Do not use for background music (generate_task_music), dialogue or narration (generate_speech), or for editing Sound Cues and MetaSounds inside the engine.

Sound effects

Quick start

Always call generate_sound_effect first. It decides the route:

• mode: "cloud" — the user bound ElevenLabs. The WAV files are already made and saved to the

asset library under AIGC/音效. Go straight to Check the result.

• mode: "local" — nothing is bound. The result gives ffmpeg (the executable path) and

outputDir. Synthesize with run_shell_command using references/ffmpeg-recipes.md.

• ffmpeg is null — tell the user the two options in one sentence: install FFmpeg, or bind

ElevenLabs under 偏好设置 → 模型来源 → 音效生成. Do not try other tools.

Workflow

1. Pin down the request. One sound per call. Write the prompt as source + material + action +

space: "footstep, leather boot on wet stone, single step, close, dry". For several different sounds, make separate calls; variants is only for versions of the same sound.

1. Pick the length. One-shots (click, hit, footstep): leave seconds empty in the cloud route;

0.05–0.4 s locally. Impacts and explosions: 1–3 s. Loops: loop: true, 5–15 s.

1. Pick the route honestly. Local synthesis is good at UI clicks, beeps, retro pickups,

lasers, whooshes, noise-based impacts and wind or hum loops. It cannot make realistic recorded-sounding material (gravel steps, glass, voices, creatures). When the user wants those and only the local route is available, say so before synthesizing, and offer binding ElevenLabs.

1. Make variants for repeated sounds. Footsteps, gunshots and impacts play many times in

a row; deliver 3–4 variants (variants: 4 in the cloud route, different seed locally) so the user can randomize them in a Sound Cue or MetaSound.

1. Check the result (see below), then give every file as a local audio link.
2. Import on request. Pass the paths to ue_content_import. Mention that loops need

Looping enabled on the Sound Wave, and that 3D positioned sounds should stay mono.

Check the result

A successful tool call only proves a file exists. Measure each file with FFmpeg before delivering (command in the recipes reference):

• Duration matches what you intended.
• Peak is about -1 dBFS: not clipping (0 dBFS) and not inaudibly quiet (below -20 dBFS).
• Not silent: RMS above -40 dBFS.

These numbers say nothing about whether it sounds right. You cannot hear the file: say that plainly and ask the user to listen. For loops, ask them to preview with looping on and listen for a click at the seam.

Constraints

• Cost: in the cloud route every variant is billed separately. Default to 1 unless the sound

repeats in game. Identical parameters reuse the existing file at no cost.

• Do not change the prompt and retry after a cloud failure until the cause is known; quote the

error. If the error says a previous submission is unconfirmed, tell the user; do not delete the receipt yourself.

• Never overwrite a file the user already has; write new names into outputDir.
• Output format is fixed: WAV, 16-bit PCM, mono, 48 kHz locally. UE does not import MP3.

Failure handling

• FFmpeg filter error: read the stderr line naming the filter, fix that filter only.
• The shell tool is missing (no Git Bash on the machine): the local route is unavailable; offer

ElevenLabs instead.

• Cloud request rejected (HTTP 4xx): nothing was charged; report the provider's message.

Escalation

Ask the user when the request mixes music and effects ("给这段加点音效和配乐"), when they want a specific licensed sound library, or when a realistic sound is required but only local synthesis is available.

Trigger and non-trigger examples: references/trigger-examples.md.