🎛 Group Switch - LD

The old way was invisible, and that was the problem

A big H3 canvas isn't one graph - it's several rails living on the same canvas: a text-to-video rail, an image-to-video rail, a reference rail, a multishot chain, a music path. When you want the multishot rail instead of the single-shot one, someone has to switch it. The classic solution was a switch node that silently picked a model or a sampler mid-wire. And when one of those broke, you had nothing to look at: the wires looked identical in every mode, and the only way to find out what actually ran was to read the node's source. Lazy, opaque, and the opposite of debuggable.

Group Switch - LD (🎛 Group Switch - LD under LD / PromptMaster / Video rail, part of Lora-Daddy's PromptMasterLD pack) does the opposite. Instead of routing values through invisible logic, it drives ComfyUI's own group bypass - the same greyed-out mechanism you toggle by hand when you right-click a group. The answer to "what's switched on" is literally the canvas in front of you: greyed groups are off, full-colour groups are running. If something's off, you can see it and turn it back on yourself.

How it works

You own a plain-text mapping, one line per mode:

multishot = FL2VA, CHAIN
music     = MUSIC
image     = IMAGE

Group names match from the start and ignore case, so VIDEO catches a group called VIDEO - H3 (bypass when not making video). Groups named on the active line get switched on; every other group mentioned anywhere in the mapping box gets bypassed; groups you never mention are left exactly as you set them, so notes, previews and anything you're hand-managing survive untouched.

The mechanism runs in the browser, because group bypass is canvas state - a backend node can't flip it for you. The node's run() mostly hands back which mode is active, so you can wire active_mode onward if you want it.

Inputs worth knowing

• mode - the dropdown: auto, the eight modes (t2v, i2v, ref, ext, multishot, multishot_mp3, music, image), and off. off is the one to use while you're rearranging the canvas - it parks the whole thing without deleting your mapping.
• mapping - the multiline mode→groups table above.
• apply - off disables the switch without wiping your mapping.
• studio_mode (optional, STRING) - wire H3 Studio's mode output here and, with mode set to auto, the controller follows whichever tab that Studio panel is on. That turns the thing deciding your routing into a cable you can see rather than something listening in the background. Leave it unwired and the dropdown drives by hand.

Output is a single active_mode STRING telling you which line was applied.

How to install

GroupSwitchLD ships with PromptMasterLD, so the install is the pack install:

cd ComfyUI/custom_nodes
git clone https://github.com/Lora-Daddy/PromptMasterLD
cd PromptMasterLD
pip install -r requirements.txt

Restart ComfyUI, or grab it via ComfyUI Manager by searching "PromptMasterLD".

Where people get burned

Two gotchas, both about the mapping semantics. First: only groups on the active line get switched on, and every other group mentioned anywhere in the box gets bypassed - so if you name VIDEO on the t2v line, VIDEO is bypassed the moment you switch to a mode whose line doesn't name it. If you have a group you always want on, don't put it in the mapping at all; unnamed groups are left alone. Second, since the real work happens in the browser, this is a node for interactive use - running a workflow headless or through the API without the canvas attached isn't where its party trick lives.