LogicUtil_Debug Combo Input

Debugging ComfyUI is mostly console-reading: you run the queue and stare at the terminal to see what a node actually did. LogicUtil_Debug Combo Input is a node built for exactly that. It's a dropdown with three values - 0, 1, 2 - and when the queue runs, it prints the selected value to the console and passes it through as a STRING output. That's it. No processing, no cleverness, a literal echo.

How it works

The input input1 is a fixed combo widget (default 0). On execution the node calls print(input1) - so whatever you selected appears in the ComfyUI terminal - then returns it unchanged as a STRING. Because the output is a string, you can wire it anywhere a string is accepted and use it as a tiny controllable test value: change the dropdown, re-run, and check that the downstream node reacts the way you expect.

Its real value is as a teaching/verification tool: it gives you a known value flowing through the graph. When a downstream node misbehaves, run this with 0, then 1, then 2, and you can tell whether the problem is in the wiring or in the consumer. It's also handy for confirming the queue actually reaches a section of your graph - if the console doesn't print your selection, that branch never ran.

Where it fits

Honestly: it's a debugger and a test-signal generator, and it's thin on purpose. You're not going to ship a production workflow containing one. But when you're building a logic-heavy graph and a switch or conditional isn't firing, a known-good value upstream is the fastest way to isolate why. It lives in the pack's LogicUtil set (the LogicUtil_ prefix marks it as a port of aria1th's ComfyUI-LogicUtils), where it sits next to the pack's text-preview and error-injection nodes as part of the debugging kit.

Install

Ships in ComfyUI-JDCN. ComfyUI Manager → Install Custom Nodes → search "JDCN", or:

cd ComfyUI/custom_nodes
git clone https://github.com/daxcay/ComfyUI-JDCN.git
pip install -r requirements.txt

Only pack dependency is piexif (plus psutil, already in ComfyUI). No models.

Gotchas

• The dropdown is fixed at 0/1/2. You can't type arbitrary values; if you need a different test value, use a static number or string node instead.
• Console, not canvas. The output is the value as a string, but the printout is where the debugging happens - if you're running ComfyUI as a desktop app, make sure you can actually see the terminal it launched from, or you'll never spot the print.
• It doesn't validate anything - it's an echo, not a checker. The value that comes out is the value that went in, unfiltered.

Not a node you'll need daily. But the day a conditional branch silently refuses to fire, a three-option dropdown feeding the suspect node will tell you in two runs whether the graph or the logic is lying.