Mpi Prompt Bridge

Every graph eventually needs a wire to take a long detour - across a region of unrelated nodes, around a group - and a plain reroute only carries one value. Mpi Prompt Bridge is the ComfyUi-MpiNodes answer for the prompt system's two most common traveling companions: a prompt_list and its seed, forwarded together unchanged. It's the plumbing equivalent of a labelled reroute that happens to handle two wires at once.

How it works

Both inputs are optional, which is the tell that this is a pure pass-through:

• prompt_list - the PROMPT_LST to forward.
• seed - the INT seed to forward (with a widget default of 0 if you leave it unwired).

It outputs both values back out - prompt_list and seed - exactly as they came in. The source is three lines: return what you got. No randomization, no selection, no transformation. If you leave the prompt_list unconnected, it forwards an empty list, which is a harmless no-op rather than an error.

When you'd actually reach for it

Two genuine uses. First, layout: if your processor lives on the other side of the canvas from your lists, this node lets you carry the bundle across a messy middle without dragging a raw wire through the noise - rename the node title and it reads like a labelled lane. Second, seed coordination: because it forwards the seed alongside the list, you can tap the seed out at the far end without breaking the chain, keeping the whole prompt system on one consistent seed.

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 node does nothing, and that's fine - it's a bridge, not a processor. The pitfall is expecting more from it. It won't merge, gate, or randomize; if you find yourself wishing it did, you want MpiPromptListJoin (to bundle) or MpiPromptListSelector (to choose). It also won't rescue a broken graph - if nothing's showing up downstream, the problem is upstream, and a bridge just faithfully carries the empty result. Keep it for organization and seed-passing, and you'll never be disappointed.