Examples
Note: Nowadays I prefer the "LLM Provider" node over "LLM Model". Be sure to customize your providers.yaml, or if you prefer it, swap back to the "LLM Model" node.
Also note: In all examples (so far), the "Text Latch" node is completely optional and is just there to provide visibility to the generated prompts.
prompt-enhancer
Uses a system prompt posted by a now-deleted account on reddit. Though helpfully, the comment still remains.
img2text2img
This just takes the example Stable Diffusion 3.5 Medium workflow but replaces the prompt with LLM output.
The YALLM nodes query a (vision) LLM, asking for a description of the loaded image.
prompt-optimizer
Asks the LLM to optimize a prompt by word count while keeping descriptive details. Uses the "String Function" node from https://github.com/pythongosssss/ComfyUI-Custom-Scripts/ in order to prepend some text to the original prompt in order to use it as a system prompt.