DebugPrint

ComfyUI gives you plenty of ways to see images and almost no way to see the plain values moving through your graph. DebugPrint is the exception: you wire anything into its single ANY input, and it dumps that value to the console. The whole implementation is print(ANY). That's not a simplification - that's literally the node.

It's an output node with no outputs, so it's a dead end by design: a debug tap you attach to whatever you're curious about, not something you build on. Wire it off a Compare node to confirm a and b are what you think they are. Wire it off a text node to see whether that string is actually empty. When a workflow is silently doing the wrong thing, this is how you find out what it's doing.

Where the output goes

Not in the browser. The print lands in the terminal or console where you launched ComfyUI - the same window that shows startup logs. If you launched it with python main.py, that's where to look. As a sanity check: when the pack loads you'll see a colored line, "theUpsiders Logic Nodes: Loaded," in that same console. If you don't see that line, the pack isn't loaded and this node won't be either.

Gotchas

• It prints every run, unconditionally. There's no toggle, no "print once." Every time the graph executes and this node is in the path, you get a line. Fine for debugging; remember to delete it before you call the workflow "done."
• Don't feed it a tensor. Printing a latent or a big image tensor dumps a wall of numbers into your terminal and tells you nothing. It's for scalars, strings, and small lists - the values, not the heavy payloads.
• It only runs if it's connected. A dangling DebugPrint node isn't executed, which is itself a debugging lesson: if you expect a print and see nothing, check that the branch it hangs off actually runs.

This fits the community debugging playbook perfectly: change one variable at a time, keep the seed fixed, and look at the intermediate value before changing the next thing. That's what this node is for - reading the variable.

Install

Via ComfyUI Manager (search ComfyUI-Logic) or:

cd ComfyUI/custom_nodes
git clone https://github.com/theUpsider/ComfyUI-Logic

Restart ComfyUI and you're done - no requirements.txt, no model downloads, one Python file. The repo is unmaintained per its own header, but print() hasn't needed a patch yet.