{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://schemas.sogni.ai/creative-agent/2026-04-27.1/tools/extend_video.schema.json",
  "title": "extend_video arguments",
  "schemaVersion": "2026-04-27.1",
  "description": "Extend a video by adding new time to the end. For LTX 2.5/2.3 base clips, the tool extracts the last frame and renders an image-to-video continuation; new non-Seedance continuations default to LTX 2.5. For Seedance base clips, it preserves the Seedance path. Returns both the standalone new segment and the spliced composite while preserving the original base bytes, audio, and timing.",
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "prompt": {
      "type": "string",
      "description": "What should happen during the extension — describe motion, action, dialogue, and audio for the appended seconds, NOT the entire video. For LTX continuations, preserve user-provided spoken dialogue in double quotes; if speech is requested without exact words, describe the delivery without inventing quoted dialogue. If the user did not specify what should happen, write a brief continuation that preserves the existing tone (e.g. \"the scene continues with the same camera and pacing\")."
    },
    "duration": {
      "type": "number",
      "description": "Length in seconds of the new appended segment (NOT total final length). LTX 2-20, Seedance 2.0/Mini 4-15, Seedance 2.5 4-30. Default: 5.",
      "minimum": 2,
      "maximum": 30
    },
    "videoIndex": {
      "type": "number",
      "description": "Which video result to extend. Default: -1 (most recent video in this session). Use 0-based non-negative indices for prior tool result videos. Use negative indices for uploaded videos: -1 = most recent video result OR first uploaded video when no prior render exists."
    },
    "videoModel": {
      "type": "string",
      "enum": [
        "auto",
        "ltx25",
        "ltx23",
        "seedance2",
        "seedance2-mini",
        "seedance2-5"
      ],
      "description": "Which model to use for the new segment. Default: \"auto\" — preserve Seedance for a Seedance base and otherwise use LTX 2.5. Use ltx23 only for explicit rollback. \"seedance2-5\" supports 480p/720p and 4-30s of new footage at 24 fps."
    },
    "keepOriginalAudio": {
      "type": "boolean",
      "description": "Has no effect for extend_video (the new segment is appended after the base, so the base audio is always preserved through the original portion and the new segment carries its own audio). Reserved for parity with replace_video_segment."
    }
  },
  "required": [
    "duration"
  ]
}