# Stable Audio 3 Small music outpainting fal AI

Needs prompt and audio url.

Stable Audio 3 Small Music Audio Outpainting, served by fal.ai. $0.0265 per audios One submitted item is offered per call; the exact receipt determines the final charge. Asynchronous: returns a request_id; poll fal/status and fetch fal/result with model "fal-ai/stable-audio-3" and that request_id. The exact endpoint/request billing receipt is required before settlement.

- Tool ID: `fal/fal-ai-stable-audio-3-small-music-audio-outpainting`
- Name in the catalog: Stable Audio 3 Small Music Outpainting
- Provider: [fal.ai](/providers/fal.md)
- Capability: [AI audio](/tools/audio-generation.md)
- Price: $0.0265 per call
- Authentication: an authorised Agentik workspace is required for execution, including zero-price tools.

## Pricing contract

The provider’s price, with no markup. Billed for measured usage.


```json
{
  "model": "per_call",
  "amountUsd": 0.0265
}
```

Pricing source: [https://fal.ai/models/fal-ai/stable-audio-3/small/music/audio-outpainting/llms.txt](https://fal.ai/models/fal-ai/stable-audio-3/small/music/audio-outpainting/llms.txt). $0.0265 per audios One submitted item is offered per call; the exact receipt determines the final charge..

Price verification date: 2026-11-03.

## Complete input schema


```json
{
  "type": "object",
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "Text description guiding the extension content.",
      "type": "string"
    },
    "seed": {
      "title": "Seed",
      "description": "Random seed for reproducible outputs. Omit for a random seed.",
      "anyOf": [
        {
          "type": "integer"
        },
        {
          "type": "null"
        }
      ]
    },
    "guidance_scale": {
      "title": "Guidance Scale",
      "default": 1,
      "minimum": 0,
      "description": "Classifier-free guidance scale. Higher values follow the prompt more strictly. Only effective on base (non-distilled) checkpoints.",
      "type": "number",
      "maximum": 25
    },
    "num_inference_steps": {
      "title": "Num Inference Steps",
      "default": 8,
      "minimum": 1,
      "description": "Number of sampling steps. Post-trained (distilled) checkpoints look good with the default 8 and gain little from going higher.",
      "type": "integer",
      "maximum": 100,
      "enum": [
        8
      ]
    },
    "audio_url": {
      "title": "Audio Url",
      "description": "Source audio to extend.",
      "type": "string"
    },
    "extend_seconds_after": {
      "default": 0,
      "type": "number",
      "maximum": 120,
      "title": "Extend Seconds After",
      "description": "Seconds of new audio to generate after the source audio.",
      "minimum": 0
    },
    "output_format": {
      "title": "Output Format",
      "default": "mp3",
      "description": "Container format for the generated audio output.",
      "type": "string",
      "enum": [
        "mp3",
        "wav",
        "flac",
        "ogg",
        "opus",
        "m4a",
        "aac"
      ]
    },
    "bitrate": {
      "title": "Bitrate",
      "default": "192k",
      "description": "Audio bitrate for compressed output formats (e.g., mp3, aac, opus). Format e.g. '192k' or '320k'. Ignored for lossless formats (wav, flac).",
      "type": "string"
    },
    "negative_prompt": {
      "title": "Negative Prompt",
      "default": "",
      "description": "Text description of qualities to avoid in the output.",
      "type": "string"
    },
    "enable_prompt_expansion": {
      "title": "Enable Prompt Expansion",
      "default": false,
      "description": "If True, the prompt will be expanded using an LLM for more detailed and higher quality results.",
      "type": "boolean",
      "enum": [
        false
      ]
    },
    "enable_safety_checker": {
      "title": "Enable Safety Checker",
      "default": true,
      "description": "Enable NSFW content safety checking.",
      "type": "boolean"
    },
    "extend_seconds_before": {
      "default": 0,
      "type": "number",
      "maximum": 120,
      "title": "Extend Seconds Before",
      "description": "Seconds of new audio to generate before the source audio.",
      "minimum": 0
    }
  },
  "required": [
    "prompt",
    "audio_url"
  ],
  "additionalProperties": false
}
```

## Published example

This is the provider tool’s published example. Replace example values with the user’s requested inputs, respecting the schema; do not execute an example merely to test a connection.


```json
{
  "tool_id": "fal/fal-ai-stable-audio-3-small-music-audio-outpainting",
  "input": {
    "prompt": "soft strings continue the melody",
    "audio_url": "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav",
    "enable_prompt_expansion": false,
    "num_inference_steps": 8,
    "guidance_scale": 1,
    "extend_seconds_after": 0,
    "output_format": "mp3",
    "bitrate": "192k",
    "negative_prompt": "",
    "enable_safety_checker": true,
    "extend_seconds_before": 0
  }
}
```

## Execute and retrieve

Inspect again before execution, explain the price and obtain the required authority. Use MCP run_tool or POST /v1/run with this tool ID, valid input and an idempotency key. Save the returned run ID and follow the actual state. If Agentik answers that the tool is temporarily unavailable, do not retry it blindly; use discovery to propose an alternative.

This tool uses deferred settlement. Follow its returned task/run instructions; preserve the existing reservation until the result is reconciled.

A partial or uncertain result can still have consumed provider resources. Consult [billing](/docs/billing.md), [idempotency](/docs/idempotency.md) and [asynchronous results](/docs/async.md).

[Provider documentation](https://fal.ai/models/fal-ai/stable-audio-3/small/music/audio-outpainting)

[REST inspection](https://api.agentik.cc/v1/tools/fal/fal-ai-stable-audio-3-small-music-audio-outpainting) · [OpenAPI](/openapi.json) · [Connection guide](/connect.md)

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[HTML page](/providers/fal/fal-ai-stable-audio-3-small-music-audio-outpainting) · [Agent index](/llms.txt)