⛔ Isulion Negative Prompt Generator

Let's get the honest take out of the way first: the negative prompt is not dead, but it is picky about who it works for. If you're on SD 1.5, SDXL, or the anime SDXL line (Illustrious, NoobAI, Pony), a good negative prompt still does real work. If you're on an LLM-encoded model like Flux or Wan, the negative box is basically inert. The Isulion Negative Prompt Generator is built for the first crowd - and it knows it.

It's part of the Isulion/ComfyUI_Isulion pack's "enhancement" trio, next to the Prompt Enhancer and Style Mixer. You drop it in, it hands you a comma-separated list of negative terms, and you wire that into the negative side of your conditioning. Nothing to configure beyond how harsh you want it.

How it works

The node keeps three hardcoded lists - basic, standard, and strict - of classic negative boilerplate: "blurry," "bad anatomy," "extra fingers," "watermark," "worst quality," and friends. It picks a random subset and joins them with commas. Basic pulls 6–8 terms, standard pulls 32–40, strict pulls a wall of 60–80. The seed input shuffles which subset you get.

The inputs that matter

There are no required inputs at all - you can drop this node in, wire up the output, and queue.

• strictness (optional) - basic, standard (default), or strict. Standard is the sweet spot for most SDXL work; strict is overkill for 95% of cases.
• seed (optional) - seed 0 re-rolls the subset each run; a positive seed locks it.

Output

A single STRING: the joined negative prompt. Wire it to the negative input of a CLIP Text Encode node, or straight to a conditioning node if you're working in a condensed setup.

Installing it

One pack, all Isulion nodes:

1. ComfyUI Manager → Custom Nodes Manager → search Isulion → Install → Restart.
2. Or clone it manually:

cd "your_ComfyUI_install_dir/custom_nodes"
git clone https://github.com/Isulion/ComfyUI_Isulion

No requirements.txt, no downloads - it's a random picker over a text list.

Common issues

Three things to know. First, the model question matters more than the node: on an LLM-encoded checkpoint this list is mostly wasted tokens, and at CFG 1 (like a distilled Flux setup) the negative prompt does nothing at all. Save it for CLIP-era models running CFG 4–9, which is exactly the population that still talks about negative prompting. Second, the lists are copy-paste-era quality - "blurry" and "cloned face" show up more than once inside the standard list, and terms like "mutated hands, extra fingers" are aimed at anime-checkpoint failure modes. Duplicates are harmless, but know what you're pasting. Third, strict mode's 60–80 terms is bloat; SDXL only has 77 tokens of attention per chunk, so a giant negative list means your positive prompt competes with it. Basic or standard is genuinely enough - you can always add a couple of your own terms on top.