I've seen a number of prompts that put parentheses or square brackets around certain words/phrases. This seems to be used across multiple frontends (Automatic1111, ComfyUI, NovelAI, ...) and regardless of model. What does this syntax do?

  • 2
    I think this'd do better as a "how can I adjust the weights of parts of a prompt?" question, since the syntax is a tool-specific implementation detail.
    – wizzwizz4
    Jul 17, 2023 at 20:31
  • @wizzwizz4 True. Tried to capture users who've seen the syntax in-use and are unsure what it does (since it's commonly found in prompts with no explanation) - but possibly better to use your title for this post and have the syntax-specific question be separate with a brief answer (that it's used for weighting, then pointing here for details)?
    – SirBenet
    Jul 18, 2023 at 15:14
  • I'd then close it as a duplicate of this one. (Having an upvoted answer will prevent the system from deleting the duplicate.)
    – wizzwizz4
    Jul 18, 2023 at 15:18
  • See also: Some of my important points being ignored in text-to-image generation. How to emphasize it to be in the image? – if you edited this question, it could be a good duplicate target for that one.
    – wizzwizz4
    Jul 19, 2023 at 8:30
  • 1
    The tag image looks to me to be a meta tag. I suggest replacing it with the tags image-generation and prompt-design.
    – Wicket
    Jul 24, 2023 at 20:57

1 Answer 1


Square brackets and parentheses are used for adjusting the weight of the contained words:

  • Surrounding words with (parentheses) will increase their impact on the image,

  • Surrounding words with [square brackets] will decrease their impact on the image.

You can further increase/decrease the weight by adding (((more))) pairs, or explicitly specify a weight value (like this:1.2). Here's the same prompt/seed weighted differently:

Generated images side-by-side showing how increasing weight of "red" causes the image to more prominently feature red, and vice versa

Be aware that this is implemented per-frontend, so the specifics may differ slightly. For example, NovelAI uses {curly brackets} instead of parentheses, and Automatic1111 normalises weights across the prompt. Documentation:

  • 1
    Is there something similar for generative language models? Aug 13, 2023 at 13:25

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