Bool

Bool Mecha Hyper is the least glamorous node in the Mecha Merge Node Pack: a checkbox that produces a MECHA_RECIPE. But it exists for a reason - in comfy-mecha, even boolean parameters are recipes. When a merge method wants a flag like rescale or vote_sgn, the slot is typed MECHA_RECIPE, and something has to hand it a boolean wrapped as a recipe. That something is this node.

Where it plugs in

The merge methods in this pack - auto-registered from the sd-mecha library - have a bunch of boolean knobs you'd otherwise not be able to reach. The TIES family is the biggest user:

• rescale on TIES-sum-style merges - whether to rescale the merged delta after pruning so magnitude isn't lost.
• vote_sgn - whether to compute a per-position majority sign and discard dissenting values (the actual "TIES" step).
• use_approximate_basis on Truncate Rank - whether to use a cheaper approximate SVD basis rather than a full decomposition.

Wire Bool into those slots and you get a clean on/off for a behavior that changes the math substantially. Default on the node is false, and it outputs a single recipe of type MECHA_RECIPE.

How it works

Same as its siblings Float and Int: the boolean is wrapped as a literal param recipe. Nothing is merged at this stage - the recipe graph only executes when Mecha Merger runs it, key by key, which is the whole memory story of this pack. The (delta|param|weight) suffix you'll see on recipe sockets is telling you which merge space an input lives in; a boolean lives in param space, so Bool plugs into any param-typed socket without drama.

Install

ComfyUI Manager → search mecha → install Mecha Merge Node Pack, or:

cd ComfyUI/custom_nodes
git clone https://github.com/ljleb/comfy-mecha.git
pip install -r comfy-mecha/requirements.txt

Restart, done. Only dependency is sd-mecha==1.1.7; no model files are downloaded by the pack itself.

Gotchas

The trap is the same one that catches people on Float: the default false is a real value, not "no value." If you drop a Bool onto a socket expecting true and forget to flip it, your merge quietly changes behavior - e.g. Truncate Rank suddenly uses the full SVD instead of the approximate basis, which is slower but also more exact, so it's not always a mistake. When a merge looks different than last run and you changed nothing else, check the boolean recipes upstream. And if you genuinely never touch these flags, you can ignore the node entirely - the pack's recipe nodes ship sensible defaults, and Bool is only for when you need to override one.