H3 Story Director

H3 Story Director is the flagship of this pack and the reason the pack exists: a multimodal planner that turns a story idea, up to four character reference images, and optionally a source video into a complete, validated MiniMax H3 plan. It's not a prompt enhancer - it's a production planner. It calls a vision model on OpenRouter (x-ai/grok-4.20 by default), gets a structured plan back, validates that plan locally, and only then hands you a plan_json plus the first ready-to-render prompt. The node, not the model, enforces your scene count, duration, and steps.

If H3 is the model that follows a good prompt to the letter, this is the thing that writes the letter. Given how strong H3's prompt-following is, the output quality ceiling here is genuinely high - and so is the cost of a plan that's silently wrong.

How it works

Director Mode picks the production path. Continuous Story preserves pose, action, camera, location and sound from scene to scene. Cinematic Cuts resets camera, framing, lens, pose and movement after every hard cut while keeping identity and narrative state. Edit - with a VHS IMAGE frame batch connected - analyzes <Video 1> and infers motion transfer, character replacement, wardrobe, environment or object editing straight from your prompt, with no separate operation selector.

For video analysis it samples video_sample_frames (10 by default) uniformly across the VHS batch and sends each as a separate full-detail image, reconstructing one chronological interpretation. That analysis comes back as source_video_analysis so you can check what it thinks your clip does.

The rest is a continuity machine: strict <Picture 1..4> tag assignment, stable S1–S4 subject labels, and - yes - explicit handling for adult content, describing clearly visible content objectively while rejecting anything involving minors or age-ambiguous references. Genres, motion styles, dialogue languages, and an audio_content control for voice/music all feed the plan.

The inputs that matter

• api_key - OpenRouter key, masked. On hosted setups like Runpod, leave it empty and use the OPENROUTER_API_KEY env var instead.
• story_idea - optional. Leave it empty and the Director invents the whole premise from genre, motion, scene count and references.
• scene_count - use 1 for a standalone I2V shot, more for a sequence.
• scene_duration_seconds / steps - the node enforces these; the model only writes prompts.
• draft_only - keep this ON for the first run (it's the default). It blocks downstream video generation so you can review the plan cheaply.
• director_mode - the four-way production selector above.
• image_0–image_3, source_video - references.

Outputs

• plan_json - connect to plan_json_input on MiniMax H3 Context Loop Plan; the frontend syncs the accepted JSON back into the Plan node's scene cards.
• scene_prompt - the first scene's complete prompt, shared prefix included. For standalone I2V with scene_count 1, connect this straight to H3's I2V prompt input.
• mode_prompt - first prompt adapted to the selected mode.
• story_bible, synopsis, validation, usage_stats, credits_remaining, source_video_analysis - inspectable strings.

Install

ComfyUI Manager → search Vision Prompt Assistant, or:

cd ComfyUI/custom_nodes
git clone https://github.com/elgalardi/ComfyUI-VisionPromptAssistant

Restart. You'll also want a recent ComfyUI (the pack targets the newer node extension system) and an OpenRouter key. This is an API node: no local model downloads.

The workflow that works

Start with three scenes at five seconds, draft_only enabled. Run it, review the cards that sync into the Chain Plan editor, then disconnect the plan_json cable and queue the workflow - Chain Plan uses its synchronized local copy, so you don't pay for another API request. Where people get burned: forgetting to disconnect, leaving draft_only on forever, or sharing a workflow JSON with the key still in it. Rotate anything that leaked, same as any API node.

Set reasoning off for speed and cost, and remember the model field is editable - the default is good, but it's not a lock-in.