ComfyUI MiniMax H3 Prompt Writer

Current release: 0.3.1 | MIT License

H3 Prompt Writer is a prompt-writing workspace for MiniMax H3 inside ComfyUI. Start with a plain-language Creative Brief, add optional image, video, or audio references, and generate an editable prompt in the format expected by H3.

It is a ComfyUI UI extension, not a workflow node. It writes prompt text for your existing H3 workflow. It does not run MiniMax H3, change the graph, or queue a video.

What's new in v0.3

• Redesigned Writer and Settings interface.
• Ollama as a simpler local setup.
• Optional API providers.
• External llama.cpp now has its own dedicated provider setup.
• Saved drafts for every mode.
• Better automatic model and context handling.
• More reliable Reference prompts.

What it does

You do not need to write MiniMax section headings, timestamps, or reference syntax by hand. Describe the video and tell Writer what each reference should contribute:

Use <Picture 1> for character appearance, <Picture 2> for clothes, and only the movement from <Video 1>. The character walks through a rainy Tokyo street at night.

Writer sends your brief, selected mode, prepared references, and the official MiniMax prompt-writing guide to the chosen multimodal prompt model. The result is an editable H3 prompt. You can change it directly, use Refine for a revision, or select Copy prompt and paste it into your H3 workflow.

Key features

• T2VA, I2VA, FL2VA, L2VA, and Reference modes.
• Up to 9 images, 3 videos, and 3 audio references in Reference mode.
• Clear <Picture N>, <Video N>, and <Audio N> labels for assigning identity, wardrobe, setting, motion, camera, sound, or other roles.
• Ordered video contact sheets with visible frame-sampling controls, so you can inspect what the prompt model sees.
• Official MiniMax base and Reference guides included for all five modes.
• Editable prompts, Refine, Copy prompt, and a separate saved draft for every mode.
• Automatic context planning and clear controls for releasing local prompt models and ComfyUI VRAM.

See Writing a useful Creative Brief for practical examples.

Choose a provider

Provider	Choose it when	Setup
Ollama	You want the simplest local setup	Install Ollama and pull a vision model
Direct GGUF	You want Writer to load a verified GGUF inside ComfyUI	Install the optional native runtime and add a matching GGUF + mmproj pair
External llama.cpp	You already run llama.cpp or want full control over its runtime	Start a multimodal llama-server and connect its root URL
API providers	You want Gemini, OpenAI, OpenRouter, or a Custom OpenAI-compatible endpoint	Connect a key or an existing endpoint such as LM Studio

Not sure? Start with Ollama. The provider guide explains the differences. The Ollama and Direct GGUF guides contain the tested local model choices.

Quick start

1. Install MiniMax H3 Prompt Writer from ComfyUI Manager and restart ComfyUI.

2. Open the floating H3 Prompt Writer button or use Extensions > H3 Prompt Writer. No graph node will appear.

3. Open Settings and choose a provider. For the recommended local setup and an 8 GB starting tier, install Ollama, open the app, and run:

   ollama pull gemma4:e4b
   

4. Choose a mode, add its media, and write a Creative Brief.

5. Select Generate prompt, review the editable result, then copy it into your H3 workflow.

For Git, ZIP, Windows Portable, update, and provider-specific steps, see Installation.

Privacy and limitations

• With Ollama, Direct GGUF, External llama.cpp, or a local Custom endpoint, the prompt request and prepared media stay on the local machine.
• With a remote API provider, the required brief, instructions, prepared images, and video contact sheets are sent to the selected provider. Original video and audio bytes are not uploaded by Writer. Read What leaves this computer before using private media.
• Video understanding uses the ordered contact sheet shown in the preview, not every frame of the encoded video.
• Prompt models do not listen to uploaded audio. Describe the soundtrack, voice, rhythm, or other audio role in the Creative Brief.
• The interface and documentation are in English. Briefs can use other languages, and Writer preserves supplied dialogue and visible text.
• Gemma 4 is the recommended local model family and has received the most testing. Qwen 3.6 also completed all five H3 modes through Ollama without special changes to Writer.
• Ollama, External llama.cpp, and compatible API endpoints let you try other multimodal models that accept images. Compatibility does not guarantee a good H3 prompt.
• Direct GGUF is the exception. It currently supports only the verified Gemma 4 pairs because its model loader and vision-projector integration are built for Gemma 4.
• Gemini and a Custom OpenAI-compatible endpoint were tested live. OpenAI and OpenRouter have automated contract coverage but were not tested live with commercial credentials. Comfy Cloud has not been validated for v0.3.

Documentation

• Installation
• Using Prompt Writer
• Choose a provider
• Ollama
• Direct GGUF
• External llama.cpp
• API providers
• Troubleshooting
• Changelog

The project is released under the MIT License. MiniMax H3 guides and model files keep their upstream terms. Model weights are not bundled with this extension.