MiniMax H3 Scene Prompt Editor

Scene Prompt Editor is the "stop squinting at a tiny text box" node for the Contex Loop pack. A multi-scene MiniMax H3 Plan can have a dozen scene prompts with references, alternatives, and seed overrides stuffed into them - editing those in the cramped widget of a graph node is miserable. This node gives you a large, keyboard-friendly editor that's synchronized bidirectionally with each scene prompt in the connected Plan. Change a scene in the Plan, the editor reflects it; type in the editor, the Plan updates. It's a companion, not a replacement - a writing surface bolted onto the Plan.

It only touches prompts. Seeds, timing, references, schedules - all of that lives in the Plan node, and this editor doesn't go near it. That's the division of labor with the experimental Rich Scene Prompt Editor, which adds reference color-coding and previews but still doesn't touch settings.

How it works

Connect the Plan's plan output into the editor's plan input. The editor binds to that Plan's active scene prompt and stays in sync in both directions. At execution time the plan output passes the validated plan through unchanged - the editor is authoring-side sugar, not a transformation. That's why the README is comfortable telling you to insert it between Plan and Loop Start, or to hang it off an editor-only branch. Either way, your generation graph never depends on it.

Which scene is "active" is shared state, and it pays off in the review loop: when Review Gate is reviewing scene three, it selects scene three in a bound Scene Prompt Editor automatically, so you can edit and retry without hunting for the right scene in the Plan JSON. If you edit a prompt here and hit "Retry prompt / seed" at the gate, your edit is what gets submitted.

Why you want it even if the Plan widget works

Because H3 scene prompts get long, and long prompts with {option|option} alternatives and @tag references are where fat-finger edits happen. A large editor with room to breathe makes typos visible before they cost a render. It also pairs naturally with the Prompt alternatives feature - each scene's alternatives resolve to stable seeds at authoring time, and the editor is where you'd refine the template.

Outputs: plan (the connected validated plan, unchanged) and nothing else - this is deliberately a pass-through.

Install

One node from ComfyUI-MiniMaxH3-Contex-Loop. ComfyUI Manager → search "ComfyUI-MiniMaxH3-Contex-Loop", or:

cd ComfyUI/custom_nodes
git clone https://github.com/ethanfel/ComfyUI-MiniMaxH3-Contex-Loop.git

Restart. No pip deps. It needs a current ComfyUI build with native Add Guide for MiniMax H3 support for the generation side of the graph, and remember the H3 weights aren't bundled - and are geofenced out of the US/EU/UK/South Korea under the MiniMax H3 Community License if you're in those regions.

Gotchas

Two things trip people. First, this editor doesn't edit the Plan's settings - if you're tweaking seeds or durations you're in the wrong node; that's Plan Studio's job. Second, since the editor writes prompts into the Plan, a prompt edit on an already-saved scene is a change that invalidates dependent resume - editing scene two after scenes three and four are checkpointed means the resume check on scene four will flag the mismatch. That's the pack working as designed, not a bug. For a first run, connect the editor as a branch you can read from, leave the generation path wired Plan → Loop Start, and edit with confidence.