ImpactLogger

print() for your node graph. When a workflow is misbehaving and you can't tell what value or type is flowing down a particular wire, drop ImpactLogger on it and it dumps that value to the ComfyUI console during the run. It's the humble debugging tool that saves you from guessing - especially in Impact Pack's logic and loop graphs, where a wire might be carrying an int, a boolean, a SEGS, or the wildcard any-type and you genuinely can't tell by looking.

This is a developer/troubleshooting node. You add it when something's wrong and pull it once you've found the problem; it's not part of a finished workflow.

How it works

It accepts any value (the wildcard * type, so it'll take an int, an image, a SEGS, whatever), and when the node executes it writes that value - plus a label you supply - to the console/terminal where ComfyUI is running. There's no visible output node in the graph and no data passed onward; the whole result is the console line. So to see it you need to be watching the terminal (or your host's logs), not just the browser. The text field is your own note, so when you've got three loggers scattered across a graph you can tell which line came from which.

The inputs

• data (*, any type, required) - the value to log. Tap it off whatever wire you're suspicious of.
• text (STRING, multiline, required) - a label printed alongside the value, so you can identify which logger fired.

There are no outputs - it's a terminal (output) node whose product is the console line. It doesn't pass data through, so it sits on a branch off the wire you're inspecting rather than in the middle of it.

How to install it

Ships with Impact Pack. ComfyUI Manager: search ComfyUI Impact Pack, Install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/ltdrdata/ComfyUI-Impact-Pack

then pip install -r requirements.txt in ComfyUI's Python env (portable: python_embeded\python.exe -m pip ...), restart. Pack's by ltdrdata, the ComfyUI-Manager author - safe, mainstream. Nothing else to install for a debug node.

Common issues & troubleshooting

"It's not logging anything" is almost always that you're looking in the wrong place - the output goes to the console/terminal (or the server logs on a hosted setup), not the ComfyUI web UI. Open the terminal window where ComfyUI launched and you'll see it. Second, since it has no pass-through output, remember to branch to it - connect the wire you're inspecting to the logger as an additional consumer, leaving the main path intact; don't try to route your data through it. And on hosted or serverless ComfyUI where you don't have a live terminal, console prints may not surface at all, which makes this node most useful on a local install where you can watch the log stream.