video-gen

# Video Gen

Submits one video generation job per call and returns a `jobId`. Job management (wait / status) belongs to `track_progress`; this skill does **not** place videos on the timeline automatically.

## When to Use

Any time the user wants to generate a video clip — text-to-video, image-to-video, first-last-frame transition, reference-based generation, multi-shot storyboard, or generatively editing / extending an existing video (producing new generated footage based on a source clip; not timeline trimming).

## Models

| Model | Reference | Strengths |
| --- | --- | --- |
| `seedance2` | [references/seedance2.md](references/seedance2.md) | Default when configured. Multimodal refs, first/last, edit/extend/bridge, 2–15s, 480p/720p/1080p/4k, audio/seed/camera/watermark/last-frame/task controls. |
| `kling` | [references/kling.md](references/kling.md) | Technical camera/performance; Omni multi-shot; images ≤7 (≤4 with one feature `refVideos`); std/pro; 3–15s. |
| `hailuo` | [references/hailuo.md](references/hailuo.md) | MiniMax 海螺. T2V / I2V / first+last; **6s or 10s**; 512P (Hailuo-02), 720p→768P, 1080P (6s); no multi-ref / multi-shot. |
| `grok-imagine-video` | [references/grok-imagine-video.md](references/grok-imagine-video.md) | xAI Grok Imagine. Text-to-video only; 1–15s; 480p/720p/1080p; audio track included. |

**IMPORTANT:** Before generating, READ the chosen model's reference for capabilities, input channels, modes, prompt structure, and model-specific behavior. Never invent params the reference forbids.

## Model Selection

Respect **configured vendors** from the capabilities prompt (only call a model whose key is on).

1. **User named a vendor** ("用海螺", "MiniMax", "Kling", "Seedance") → that `model`, if configured.
2. Else **default `seedance2`** when Seedance is configured.
3. Else if only Kling is on → `kling`. Else if only MiniMax is on → `hailuo`. Else if only xAI is on → `grok-imagine-video`.
4. Switch away from default when:
   - Need **multi-shot customize / intelligence** → `kling` (confirm if not user-named).
   - Need **rich multi-modal refs** (video/audio refs, edit/extend) → `seedance2`.
   - Need a **short single beat** and only MiniMax is available, or user wants Hailuo → `hailuo` with duration 6 or 10.

If the required model is **not configured**, say so and offer: another configured video vendor, upload, or Motion Graphic — do not pretend the API exists.

Briefly tell the user what you will generate before submitting.

## Tool Params

| Param | Values | Default |
| --- | --- | --- |
| `model` | `seedance2`, `kling`, `hailuo`, `grok-imagine-video` | seedance2 when available |
| `durationSeconds` | model-specific | seedance/kling ~5; **hailuo 6 or 10** (1080p → 6 only); **grok 1–15** |
| `ratio` | see model docs | 16:9 (seedance/kling/grok); **ignored on hailuo** |
| `resolution` | `480p`, `512p`, `720p`, `1080p`, `4k` | provider-specific; hailuo adds 512p for Hailuo-02; grok: 480p/720p/1080p |
| `refVideoMode` | `feature`, `base` | kling only, with `refVideos` |
| `promptOptimizer` / `fastPretreatment` | boolean | hailuo only |
| `generateAudio`, `seed`, `cameraFixed`, `watermark` | controls | seedance only |
| `returnLastFrame`, `executionExpiresAfter`, `priority` | controls | seedance only; requested last frame becomes another image asset |
| `name` | descriptive asset name | required for good pool UX |
| `firstFrame` | project image asset ref | optional |
| `lastFrame` | project image asset ref | seedance / kling / hailuo (requires firstFrame; not with multi-ref on seedance) |
| `refImages` / `refVideos` / `refAudios` | asset refs | seedance full; kling: images + **1** feature video (no audio); hailuo: none (frames / S2V subject) |
| `mode` / `shotType` / `multiPrompts` | Kling multi-shot | kling only |

Model-specific params — see the model's reference.

## Input Resolution

`firstFrame` / `lastFrame` / `refImages` / `refVideos` / `refAudios` all take a project asset reference. Prefer a full UUID or short prefix from `read_project`; `asset://<id>` and same-project asset URLs returned by `read_project` are also accepted. Per-slot type: frame slots and `refImages` → image; `refVideos` → video; `refAudios` → audio.

External URLs and base64 are not accepted. If the source is a public URL, download it into the project first (`download_media` for video/audio, `submit_image` for images) and pass the resulting asset id.

## Workflow

Four-step loop. For each new generation, restart from Step 1 if the user's intent has shifted.

### Step 1 — Align scope with the user

Before writing any prompt, align on three dimensions:

1. **Duration & segments** — total length, how many shots, and whether they live in one clip or several.

   If the user has already stated a direction ("做一段", "in one video", "分别生成", "split into N shots", etc.), follow it — don't second-guess.

   Otherwise, surface the two paths and let the user pick:
   - **Multi-shot within one clip** (see model ref) — single inference, subject / lighting / style physically consistent across sub-shots; fits a coherent narrative within the per-clip duration cap.
   - **Multiple clips** — each clip is independently controllable and re-rollable, but identity and style continuity have to be carried by anchors; fits durations beyond the cap or hard scene breaks.

   Offer the trade-off; do not pick for the user.

2. **Content** — what each clip depicts. Summarize back what you understood, segment by segment. When content is vague (e.g. "generate a video of a girl dancing"), the user typically hasn't specified one or more of:
   - **Subject**: who / what is the main subject (appearance, outfit, defining features)?
   - **Action**: what are they doing? (For talking / emotional shots, what micro-expression?)
   - **Scene**: where — setting, time of day, environmental details?
   - **Lighting / color mood**: what atmosphere?
   - **Camera**: any shot-size / angle / movement preference?
   - **Style**: visual style o