Mpi Prompt Override Seed

Mpi Prompt Override Seed is Mpi Prompt Override with the options half stripped out: it produces a PROMPT_OVR that changes the seed driving a prompt list's random selection, and nothing else. When wired into a MpiPromptList's opt_override socket, it re-rolls that list's pick while the global seed - and every other list fed by it - stays put.

Why that's useful

The seed is the master key of the whole ComfyUi-MpiNodes prompt system: one seed drives every list's probability roll and option shuffle, so the same seed reproduces the same complete prompt. That reproducibility is great until it isn't. This node exists for the "everything else is right, just this one list" moment - when you've locked a composition you like but want to see what a different "hair" or "pose" does without disturbing the rest of the prompt, or when two lists genuinely should vary independently.

How it works

One input, one output:

• seed_override - if it's anything other than -1, it becomes the seed used for the target list's selection. The -1 default means "no override," which passes the original behavior through.
• override (output) - the PROMPT_OVR, wired into any MpiPromptList's opt_override input.

The source is a one-liner: it emits ("", seed_override) - empty options, seed override only. And the tooltip spells out the subtle part: changing this seed does not affect the seed the list returns. Downstream nodes keep seeing the original seed, so a list that was re-rolled here doesn't knock every later random pick off its groove.

Installing it

cd ComfyUI/custom_nodes
git clone https://github.com/MadPonyInteractive/ComfyUi-MpiNodes

Restart, or ComfyUI Manager → search ComfyUi-MpiNodes. No dependencies, AGPL-3.0 from v1.2.7 (MIT through 1.2.6).

The honest take

This is a small tool with a specific job, and it does it cleanly. The trap is forgetting the -1 convention - an override node with seed_override left at 0 will silently pin that list to seed 0, which produces the same selection every run and reads as "this list stopped randomizing." If a list goes static, check for an override on its socket and confirm it's at -1 when you meant "leave it alone." Pair it with MpiPromptOverride (which forces options) and you can control any list's fate without ever editing the list itself.