SamplerEulerAncestralCFGPP_motorway_edition

Euler A is the old friend of the sampler world - simple, fast, and happily non-convergent. SamplerEulerAncestralCFGPP_motorway_edition is a clone of ComfyUI's experimental SamplerEulerAncestralCFGPP, which takes that old friend and runs it under CFG++ guidance theory. You can think of it as "Euler ancestral, but the guidance math is flipped." Where normal classifier-free guidance pushes the prediction away from an unconditional pass and needs a negative prompt, the CFG++ family reinterprets guidance as a positive-only correction - which is why these nodes are marked _for_testing in ComfyUI and why you'll occasionally see them in "no negative prompt" workflows.

Like every node in this list, it's a sampler factory, not a drawing node: feed it a model, get a SAMPLER object for SamplerCustom's sampler port. And like every ancestral sampler, it doesn't converge - each step injects fresh noise, so changing the step count changes the image rather than refining it. If you want a bit of creative variance with the CFG++ flavor, this is the one.

The knobs are the ancestral standards, but notice the ranges:

• eta (default 1.0, max 1.0) - the extra-noise scale. The CFG++ version clamps this to 1.0, so there's a hard ceiling on how much noise you can stir in.
• s_noise (default 1.0, max 10) - per-step stochastic noise strength. Also tighter-bounded than the plain Euler A (which allows up to 100); these caps are ComfyUI's own, not something this pack added.

What it does on the Motorway

This is one of the generated *_motorway_edition clones from the ComfyUI_agilly1989_motorway pack. The pack's concept: a named-key data bus - the Motorway - where you stash values under typed key names and read them back later, instead of dragging wires port-to-port. MotorwayStart creates a bus, Motorway AxB ramps store and fetch keys, and every motorway-edition node is a clone of a built-in ComfyUI node re-plumbed to pull its inputs from the bus by key and push its outputs back by key, always returning the bus so the chain flows.

The model comes off the bus by key (the family convention, INPUT_…_key; the SDTurboScheduler edition spells it INPUT_model_key with default model), and the finished sampler is written back under your OUTPUT_SAMPLER_key (default SAMPLER). Point a later motorway node at that key and it's got a sampler.

Installing it

It ships inside ComfyUI_agilly1989_motorway - no standalone download. ComfyUI Manager: search ComfyUI_agilly1989_motorway, install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

No extra dependencies, no model files - pure glue over ComfyUI's own nodes.

The catch

Two layers of "experimental" here. The underlying sampler is ComfyUI's own _for_testing CFG++ code, so don't expect it to be the community's default pick - the CFG++ family is a curiosity for people who like poking at guidance theory. And the pack layer: release 1.1.7 ships with the clone nodes disabled, so unless you uncomment the two ClonedNodeMapping lines in custom_nodes/ComfyUI_agilly1989_motorway/__init__.py and restart, this node won't be in your menu. The README also leads with "BIG BROKEN WITH ASYNC WILL FIX WHEN I GET THE TIME/MOTIVATION" and promises only "most" clones work. Tinker with it, enjoy it, just don't build your house on it.