MiniMax H3 prompt guide: reference jobs, negative direction, length
The MiniMax H3 prompting rules that change output: give each reference a job, write timecodes, say what to avoid, and stay under 7,000 characters.
The prompting habits that matter most for MiniMax H3 are to give every reference an explicit job, to write shots with timecodes, to direct the sound, and to state what to avoid. These come from fal's H3 guide and MiniMax's own prompt guide; prompts can be up to 7,000 characters, per MiniMax's API docs.
Guide content is from fal and MiniMax pages; request fields from the Sume Video generation docs, read 2026-09-29.
How do I write references into the prompt?
fal's guide: "Use Image 1 for the overall mood, location, and film texture; Image 2 for the talent; Image 3 for the bag; and Image 4 for the closing brand mark." MiniMax's guide tags images as <Picture 1> and <Picture 2>. Number the references in the order you send them in input_references, and check the output.
What should I say to avoid?
fal calls negative direction "unusually effective here". Its examples include "No soft dissolves or fluid morphs", "Do not introduce Chinese text, garbled characters, or misspellings" and "Do not show subtitles, added text, platform watermarks, or stickers". Put these inside the prompt; Sume's H3 request has no separate negative prompt field.
What are the main conventions?
| Topic | Convention | Source |
|---|---|---|
| Shots | [Shot 1] labels or [0–2 seconds] blocks | MiniMax; fal |
| Camera | Motion type, amplitude and speed, written as natural English within the shot | MiniMax |
| Sound | Describe small sounds and music deliberately | fal; MiniMax |
| Voice | "Match the voice in Audio 1" | fal |
| Text on screen | Do not translate on-screen text | MiniMax |
| Length | Up to 7,000 characters | MiniMax API docs |
Does Sume's prompt limit match?
Sume's docs do not state a prompt character limit for H3, so the 7,000 figure is the provider's. Keep prompts inside it.
Sources
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