MiniMax H3 Prompt Pack Bridge

The MiniMax H3 Extender has a per-clip prompt card for every clip in your sequence, which is great until you're building a 40-clip sequence and want the prompts to come from somewhere else - a text file, a story generator node, an LLM node writing dialogue per scene. MiniMax H3 Prompt Pack Bridge is the connector for that. It collects a series of STRING inputs and packs them into a single H3_PROMPT_PACK that plugs straight into the Extender's prompt_pack input.

What it is, precisely

It's a bundle node - the plumbing-layer pattern where a dozen values travel down one wire instead of forty loose connections. In this case, the "values" are clip prompts. The first input, prompt_1, is required; after that the node dynamically grows more inputs as you connect them, up to 128 (prompt_2 through prompt_128). The output is a single prompt_pack socket plus prompt_count, so you can see at a glance how many prompts made it in.

Two behaviors matter when you're wiring it:

• It's an ordered list, and it compacts holes. Disconnect prompt_5 and every later prompt moves up one slot. That's deliberate - a pack is a list of scenes, and a hole in the middle would shift your whole story.
• Unchanged packs don't rewrite. The bridge hashes the prompt list, and the Extender only re-imports a pack when the hash changes. Idempotent, which keeps repeated runs from clobbering clip cards you've already edited by hand.

When you connect the prompt_pack to the Extender's matching input, the prompts get imported into the normal clip textareas and the clip count synchronizes. From that point the clips behave exactly like hand-typed ones - you can still edit, validate and retry individual clips.

Why it exists

The Extender's README frames it as support for "an external prompt pack." The use case is basically: you don't want to type 60 clip prompts into cards, you want them generated or loaded programmatically - a prompt-generator node producing a scene list, a batch of prompts from a file, whatever. This is the clean seam between "where prompts come from" and "the Extender's internal state."

Install and gotchas

Same pack, trivial install:

cd ComfyUI/custom_nodes
git clone https://github.com/tritant/ComfyUI_MiniMax_H3_Extender.git

Restart ComfyUI (or Manager → MiniMax H3 Extender).

The one thing to remember: empty inputs are skipped, so if you wire a middle slot to a node that returns an empty string, the pack treats it as absent and compacts - your clip numbering follows the non-empty prompts, not the socket numbers. And it will error if it receives no non-empty prompts at all, which is a reasonable "you forgot to connect anything" signal rather than a mystery. Worth knowing before you build a 100-prompt graph and stare at a red node.