--- name: scenario-seedance description: "Use when generating or editing video with Seedance models on Scenario via MCP: text-to-video, image-to-video, first and last frame anchors, reference-to-video from identity, product, or world references, prompt-based editing, extending a clip, audio-conditioned motion or voice, shot sound without music, first-frame versus reference conditioning, or an output blocked by moderation. Keywords: Seedance 2.5 and 2.0, ByteDance, T2V, I2V, V2V, native audio, OutputVideoSensitiveContentDetected." license: MIT --- # Scenario Seedance Video ## Overview Seedance, ByteDance's video family on Scenario, folds every mode below into one model that infers which from your inputs, so the conditioning you pass decides more than prompt wording. Discover it with `search` and treat `model_schema_get` as the contract: members ship side by side, agreeing on the shape and disagreeing on every number. Connection and the core loop: see the `scenario` skill in this repo; model-agnostic video work: the `scenario-video` skill; choreography held across cuts from a storyboard: the `scenario-seedance-storyboard` skill. If a sibling skill named here is missing from your available skills, ask the user to install it (`npx skills add scenario-labs/skills --skill `); unattended, proceed from tool schemas and flag the gap. ## Quick reference Mode follows from the inputs (names from the live schema): | Mode | Inputs | Behavior | | ------------ | --------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Text | `prompt` | `aspectRatio` honored (21:9 through 9:16) | | First frame | `image` (+ `prompt`) | opens on that frame; `aspectRatio` ignored, size follows `resolution` and may land only near the ratio | | First + last | `image` + `lastFrameImage` | `lastFrameImage` is only valid alongside `image` | | Reference | `referenceImages` | carries identity and world, not the opening state | | Edit | `referenceVideos` + edit prompt | requires `duration: -1`; output follows the source | | Extend | `referenceVideos` + extend prompt | inferred from wording: "extend @video1", what holds (character, wardrobe, light), the action that continues, no cut; geometry follows the source; `duration` is the footage appended and the output holds only that tail (a 10 s source with `duration` 15 returned 15 s of new footage at authoring time; Auto priced as the source length), so concatenate source and tail and read the delivered length off `asset_get` | `image` and the reference arrays are mutually exclusive. `referenceVideos` (motion conditioning) and `referenceAudio` (timing and energy, or a speaker's voice) combine with `referenceImages`; on the 2.0 line reference audio also requires one image or video reference, where 2.5 takes it alone. Reference parameters are arrays even for one asset. Prompt tags bind by array order: `@image1` is `referenceImages[0]`, likewise `@video1` and `@audio1`, and the prompt says what each tag governs and what it leaves alone ("@image1 defines the bottle and label, nothing of the set"), for video and audio tags as much as for images. No seed, mask, or camera parameter exists: camera moves live in the prompt, one dominant move and one action per shot. Several actions go as timecoded beats ("0-2s ... 2-4s ..."), one per beat, the last ending inside `duration`, the shot named as one continuous take. A reference track the prompt does not claim is easily ignored, a generated voice line most of all, so bind it to a role in words: "@audio1 is her own voice; she speaks it to camera, lips in sync" for speech, "the camera move and each action land on the beats of @audio1" for music. `duration` defaults to Auto, which on 2.5 at authoring time priced a text-to-video job as the full 30 second cap (the same 480p prompt quoted about four times its 8 second price). Set the seconds the shot needs on every run; with `referenceVideos`, Auto follows the longest reference clip instead. Caps are per member, so read them off `model_schema_get`. At authoring time 2.5 took 30 reference images, 10 videos, 10 audio, 4 to 30 seconds, up to 1080p; the 2.0, Fast, and Mini hits took 9, 3, 3, and 4 to 15, with 4k on 2.0 alone and no `lastFrameImage` on Mini. Price moves further than the caps do, six times across the family for one 4 second 480p job, so `dry_run` the same job on two members before a batch. ## The conditioning rule In reference mode, frame one anchors to the base state of the reference world, and no prompt wording overrides it. If the shot must open in a specific state, render a still of it and pass it as `image`; use `referenceImages` when only identity, world, and palette matter. Deciding this per shot before generating is worth more than any prompt tuning. ## Sound from the shot, music from elsewhere `generateAudio` (default true) is one switch over the whole track: it scores the shot as well as sounding it. A score written inside a shot survives no cut, since each shot invents its own key and tempo and the next one restarts them. So run the lanes apart. Keep `generateAudio: true` for what the picture makes, footsteps, impacts, room tone, dialogue, each landing on frame, and name only those sounds ("diegetic sound only: heels on tile, room tone"). Never name what to leave out: "no music" is what the audio filter reads, and a track blocked with `OutputAudioSensitiveContentDetected` usually traces to such an exclusion, so re-run on the same model with the sound named positively before any provider switch: the filter read the wording, not the provider (see the `scenario-moderation` skill). Spoken lines go in quotes, sized to the clip's seconds, with the speaker named and the delivery in two or three words. Score the sequence once with a music model (see the `scenario-audio` skill) and lay that track over the assembled cut (see the `scenario-video-assembly` skill, or `scenario-seedance-music-video` when the song comes first): re-scoring then costs one audio run, not every shot again. The prompt is the only lever, so listen to what comes back: when music leaks in, re-run that shot with `generateAudio: false` and add sound from a sound-effects or video-to-audio model. ## When the finished video is blocked A `failed` row whose error names `OutputVideoSensitiveContentDetected` (often with `PolicyViolation`, sometimes worded as possible copyright) is the provider screening the finished render. The filter belongs to the family, so a Seedance sibling refuses the same payload and the identical retry renders it again. Handle it the way the `scenario-moderation` skill teaches: switch to another provider first, prompt unchanged apart from moving the `@image` tags to the alternative's own reference field per its schema. For `recommend`, text-to-video is `txt2video`, first-frame and reference jobs are `img2video`, edit and extend are `video2video`. Two observations at authoring time decide what comes after. A character the screen takes for existing intellectual property stays blocked whatever the wording: a studio's own well-known character failed while a lesser-known one from the same studio, prompt unchanged, passed. Weapon and harm vocabulary ("axe", "blade", "eliminated") tripped it even in a cartoon, which is where that skill's one honest rewrite belongs. When the block persists past the switch and that rewrite, on the team's own characters for example, tell the user they can write to support@scenario.com with the failed job id. Unattended, launch the switch only within the spend the task authorized; otherwise stop and report the block with the failed job id. ## Worked example: a product shot from references 1. `search` with `target="models"`, `query="seedance"`, `public=true`. Prefer the newest non-deprecated hit, e.g. `model_bytedance-seedance-2-5` (a live hit at authoring time: re-discover each session). 2. `model_schema_get` with that id: fields, caps, and defaults before anything else. 3. `upload_asset` the product stills (see the `scenario` skill) to get asset ids. 4. `model_run` with that `model_id`, `dry_run=true`, and the exact `parameters={"prompt": "@image1 defines the bottle and label. Slow dolly-in as condensation beads. Diegetic sound only: droplets on glass, soft room tone. No text, no captions.", "referenceImages": ["asset_a", "asset_b"], "duration": 8, "resolution": "720p", "generateAudio": true}` for the cost estimate; re-estimate after any change to duration, resolution, or references. 5. Repeat `model_run` with `wait=false`, then `jobs_wait` with the returned job id, re-called with `pending_job_ids` on timeout, never a second `model_run`. 6. `asset_display` the output and watch it with sound before the music goes on. ## Common mistakes - Prompting an opening state in reference mode: it will not appear; pass it as `image`. - A bare string where the schema says array: one reference still goes as `["asset_x"]`. - Combining `image` with `referenceImages` or `referenceVideos`: mutually exclusive inputs. - Leaving `duration` on Auto: on 2.5 a text-to-video job priced as the 30 second cap, not the shot's length. - Passing a voice track beside a character reference without saying whose voice it is: the model may animate the face and ignore the track. - Carrying one member's caps or price to another: 30 references, 30 seconds, and 1080p are each true of one and false of the next. - Letting shots score themselves and then cutting them together: the music restarts at every cut. - Writing "no music" into an audio-enabled prompt: the exclusion trips the audio filter; describe the sound positively, or turn `generateAudio` off. - Rendering captions, prices, logos, or UI: reserve clean space and composite text in post. - Retrying an output moderation block on Seedance or a Seedance sibling: the filter is the family's, so switch provider first (the `scenario-moderation` skill).