Bypass

Every workflow eventually needs a kill switch, and most "bypass" toggles are liars - they mute the node itself but the expensive branch upstream still runs. UtilBypass is the rare one with teeth: flip its boolean and it not only passes through None, it tells the upstream node to enter ComfyUI's native bypass mode, so the whole branch genuinely doesn't compute. Flip it back and everything resumes. That's the whole appeal: an A/B toggle for two pipelines where the losing side actually frees your VRAM instead of quietly eating it.

How it works

The node itself is almost embarrassingly simple - bypass=False passes input straight to output, bypass=True returns None. The clever part lives in the pack's JavaScript (js/bypass.js). When you tick bypass on, the extension walks back the first connection, finds the source node feeding this node, and sets its mode to bypass. Toggle off and it restores the source to normal; disconnect the wire and it cleans up after itself. One guard matters: it refuses to bypass source nodes like Load Image (nodes with no inputs), because bypassing those would produce no output at all and error out your graph.

Inputs and output

• bypass (BOOLEAN, default off) - the switch.
• input (ANY, optional) - whatever you're passing through.
• output (ANY) - your input unchanged, or None when bypassed.

That's the entire surface. Wire output into whichever downstream node you're toggling between paths.

Where this shines (and where it bites)

The classic use is swapping between two processing paths - say a fast LoRA branch and an expensive ControlNet branch feeding the same sampler. Toggle the bypass and the loser doesn't run, which is exactly what a lazy toggle should do.

The trap is that when bypassed, output is literally None. If you keep the bypassed branch wired into a node that requires a real tensor, you'll get a type error rather than a clean "off." The intended pattern is that bypassing also mutes the upstream producer, so the None never actually reaches anything that needs a value. If you bypass this node's upstream source instead (e.g. you put it after a Load Image), you're back in ordinary mute territory - still works, just not magic.

Install

Part of the IXIWORKS pack - ComfyUI Manager → search ComfyUI-VideoDescription → Install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/IXIWORKS-KIMJUNGHO/ComfyUI-VideoDescription

No extra Python packages. The JS ships in the pack's web directory, so it registers on restart automatically. It's a small node, but if you build big graphs, it's the kind of utility you reach for constantly - and unlike the generic switch nodes, it's the one that actually saves you the VRAM.