Checkpoint + VAE Cycler Loader (Nukun)

If you've read the CheckpointCyclerLoader article, you know the drill: batch a workflow across every checkpoint by letting the loader's dropdown auto-increment. NukunCheckpointVaeCyclerLoader is that same node with one extra knob - a vae_name dropdown that lets you either keep each checkpoint's embedded VAE or override it with a single external VAE across the whole run.

That override is the whole reason this variant exists. Some checkpoints ship with a VAE that's fine, and some ship with one that's honestly a liability - the classic blurry/oversaturated look that makes you reach for a known-good VAE like the SDXL or PixArt ones every time. When you're cycling twenty checkpoints for a comparison, you want the comparison to be about the models, not silently contaminated by one checkpoint's bad VAE. This node lets you hold the VAE constant while the checkpoint spins.

How it works

Mechanically it's the CheckpointCyclerLoader core (same ckpt_name combo with control_after_generate support, same MODEL/CLIP/VAE/modelname/ckpt_name/folder outputs) with a VAE-selection step bolted on.

The vae_name dropdown is the interesting input:

• checkpoint (the default) keeps the VAE embedded in the selected checkpoint. Pure cycler behavior.
• Any external VAE you have installed - selecting one overrides only the VAE output, while MODEL, CLIP, and the metadata outputs stay tied to the current checkpoint.

So the mental model is: checkpoint moves the model, VAE is either "ride along" or "locked". If you want to compare model quality with a fixed decoder, lock the VAE. If you want each model to bring its own VAE, leave it on checkpoint.

The inputs that matter

Only two. ckpt_name - the cycling dropdown; right-click → control after generate → increment to batch. vae_name - the override, as described above. The outputs are identical to the plain cycler, so this is a straight swap in any existing cycler workflow.

Installing it

Same pack, same one-time install:

cd ComfyUI/custom_nodes
git clone https://github.com/OnekoSL/Nukun_ComfyUI_Nodes.git

Restart ComfyUI (or ComfyUI Manager → search "Nukun"). No special dependencies beyond the pack's small runtime set.

A note on the default

Don't expect this node to second-guess your VAE choice for you. The default checkpoint means "embedded VAE", which is ComfyUI-core behavior - if you're seeing funky colors during a cycle run, check that you didn't mean to set an external VAE. That's not a bug; it's the node respecting that checkpoint-internal VAEs are often perfectly good. If you're on a Pony or Illustrious checkpoint, though, an external VAE is frequently the difference between washed-out and punchy - which is exactly when you'll be glad the knob is there.