LogicUtil_Text Preview

Every ComfyUI user eventually hits the same moment: your prompts are being built by three different nodes with a random picker in the middle, and you have genuinely no idea what string is actually going into the CLIP encoder. LogicUtil_Text Preview is the answer to that. It's a debug node from the LogicUtil subpack of ComfyUI-JDCN - a single text input, no outputs, whose entire purpose is to show you what it receives.

What it does

You wire any text value into the text input and queue the run. The node displays the string in its UI widget and also prints it to the ComfyUI console. That's it. It's marked as an output node (OUTPUT_NODE), meaning it's meant to be a terminal - a place for a wire to end - and it has no STRING output because it isn't supposed to feed anything; it's a window, not a valve.

The text input is the wildcard * type, so it'll accept a string from anywhere: a prompt template, the output of a random choice, a list join, even a number you want to see confirmed as text. Whatever lands there, you see it in the UI after the run.

Why this is the one to reach for

Because "I'll just check the console" is a lie you'll only tell yourself once. The printed value goes to the terminal running ComfyUI, which is easy to miss if you're not looking at it, but the widget display is right there in the graph next to the node. Combined with the community's core debugging habit - change one variable at a time with a fixed seed and compare - a preview node turns "why is my image wrong?" from guesswork into inspection. You can see whether the random picker chose the intended variant, whether a string join dropped a term, whether the negative prompt is actually the empty string you feared.

Pair it with the pack's other LogicUtil nodes and it's a nice little debugging loop: Uniform Random Choice decides, Text Preview confirms, and only then does the sampler run. If the image comes out wrong, you've already ruled out the prompt assembly.

The honest caveats

• It's purely for inspection. No outputs means no data flows through it, so it has to sit at the end of a branch - put it on a spur off your prompt wire, not inline.
• The widget shows the result after the run, so it won't update live mid-generation.
• For a terminal display node, this is the cheap option in the pack - fine for a glance, not a rich text viewer.

Installing it

It comes with ComfyUI-JDCN, so one install covers the whole LogicUtil set. ComfyUI Manager: Install Custom Nodes → search "JDCN", install, restart. Or:

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

The pack's only dependency is piexif - no models, nothing heavy. It's a small two-person hobbyist pack (Daxton Caylor and Jerry Davos), and the preview node is exactly the kind of small tool the pack is good at: nothing flashy, but the day you're debugging a prompt chain, it'll tell you more than you knew a minute earlier.