Shima Mask Pass

Shima Mask Pass is the mask-only member of the pack's Passer family: MASK in, the same MASK out, nothing computed in between. It exists for exactly one reason - to be a stable, correctly-typed landing pad for a mask signal at the edge of a Shima island.

The backstory matters here, because a bare passthrough is otherwise indistinguishable from a node that does nothing. Shima's "islands" are workflow fragments that auto-connect through the Use Everywhere broadcast system. Passers act as the airports at island boundaries: their optional, typed inputs give UE a socket it can broadcast into without ComfyUI guessing wrong about types. A mask is exactly the kind of signal that needs that anchor, because masks are everywhere in inpainting, compositing, and detail-pass pipelines, and they love to arrive in the wrong socket.

The node's execute is a one-liner - return (mask,) - which is the whole mechanism. The value is placement, not processing.

The interface

• mask - optional MASK input, echoed to the mask output. Optional means unwired is tolerated (passes None through), which is the desired behavior for a broadcast target: a run where nothing lands won't crash your graph.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/KDB-USJP/shima_wf

then restart, or ComfyUI Manager → search "Shima". No models, no extra dependencies.

Where it earns its slot

Two real uses. First, island boundaries: when a mask needs to cross from a mask-generation island (a SAM or segmentation step, for instance) into a compositing island, dropping a Mask Pass at the edge gives UE a typed target that won't get hijacked by a nearby image socket. Second, as a named waypoint: a mask that fans out to several consumers can pass through one labeled node so you can see where the signal enters. The catch is the same one as every Passer - outside the island system it's pure ceremony, and core ComfyUI plus a reroute does the same job for a hand-wired graph. If you're building Shima islands, keep it at the boundary; if you're not, you can safely ignore the entire Passer family.