Textbox (CRT)

Half the time you're debugging a ComfyUI workflow, the problem is invisible. A string got mangled somewhere upstream - a replace node ate a comma, a scheduler added a stray line - and you have no idea what it actually contains until it reaches the sampler and the prompt comes out wrong. Textbox (CRT) is the node you drop mid-graph to find out.

It's a display node with a twist. The text input is the thing you'd expect: a big editable multiline box. But there's also an optional passthrough input. Here's the clever part - if you wire a string into passthrough, the node displays that and returns it unchanged, ignoring whatever you typed in the box. If passthrough isn't connected, the node just returns the editable text.

That means the same node works two ways. Drop it on an empty wire to see what's flowing through a pipeline, or use it standalone as a plain prompt box that prints its contents to the screen. Since it's marked as an output node, it renders its text right on the canvas instead of burying it in the console - one glance and you know whether your string survived the journey.

What actually matters

• The passthrough input: this is the whole reason the node exists. Note it deliberately distinguishes "not connected" from "connected with an empty string" - the code checks for the input's presence, not its value, so a deliberately connected empty string is honored rather than falling back to the editable text.
• The text output is always the display value, so you can chain it downstream if you're also using it as a reroute.
• It's an output node, which is how it earns its keep as a debugging terminal rather than yet another string utility.

Where it fits

The CRT pack is full of string machinery - Remove Lines, String Batcher, Join Strings, prompt schedulers - and this is the inspection window for all of it. Wire the output of a String Batcher into passthrough and you see exactly what the sampler is about to receive, newlines and all. It's also the node to reach for when a workflow tutorial says "put a text box here to check the prompt," because it doubles as a live readout and a normal string source.

Install and quirks

Standard pack install - ComfyUI Manager, search "CRT-Nodes", install and restart, or:

cd ComfyUI/custom_nodes
git clone https://github.com/PGCRT/CRT-Nodes.git
pip install -r requirements.txt

No dependencies, no models. The only quirk worth knowing: because it's an output node, ComfyUI treats it as a terminal - if your graph is looping or you're running long batches, the node re-executes each pass and re-prints, which is exactly what you want for debugging and mildly noisy if you leave it in a production graph. Take it out once you've confirmed the string is good.