Negative prompting: Negative prompting is telling an AI model what to avoid or leave out of its output. Image generators often have a separate 'negative prompt' field for unwanted elements; in chat models it is a plain instruction like 'do not use bullet points.'
The term comes from image generation. Tools built on Stable Diffusion have a dedicated negative prompt box where you list things you do not want: 'text, watermark, extra limbs, low resolution.' The model steers away from those concepts while rendering the main prompt. Midjourney uses a --no parameter for the same purpose, and other tools vary, so check the current documentation.
With chat models, negative instructions are just part of the prompt: 'Do not open with a greeting,' 'Avoid the word synergy,' 'Do not invent figures; if a number is missing, write TBD.' They work, but with a catch. Language models sometimes fixate on the very thing you mention, so 'do not mention the competitor' can nudge the model toward mentioning it. Wherever possible, state the positive version instead: 'Discuss only our product.'
The most useful negative instructions target the model's habits. Tell it not to pad answers with a preview of what it is about to say, not to hedge every sentence, and not to add a closing offer to help. Keep the list short. A prompt that is mostly prohibitions gives the model little to aim at.
Example at work
A marketing coordinator generating product images for a catalog keeps a standing negative prompt of 'text, logos, watermarks, people, cluttered background' so every image comes back as a clean product shot. For the product descriptions, her chat prompt ends with: 'No exclamation points, no rhetorical questions, and do not claim anything the spec sheet does not say.'
Why it matters
Knowing how to say 'not that' saves rounds of revision, especially with image tools where one unwanted element ruins an otherwise good result. Knowing the limits, and that positive framing usually works better for text, keeps your prompts short and effective.
Related terms
- PromptA prompt is the text (and sometimes files or images) you give an AI model to tell it what you want. A good prompt states the role the AI should play, the task, the relevant context, the output format, and any constraints.
- Text-to-imageText-to-image is generative AI that creates a picture from a written description. Tools such as Midjourney, Adobe Firefly, and the image generator built into ChatGPT turn a prompt like 'a product photo of a blue water bottle on white' into a finished image.
- Diffusion modelA diffusion model is a type of generative AI that creates images, audio, or video by starting with random noise and removing it step by step until a coherent result matching the prompt emerges. Most image generators of recent years are built this way.
- Prompt engineeringPrompt engineering is the practice of writing and refining instructions to get reliable, high-quality output from an AI model. It covers giving context, showing examples, specifying format, and iterating on what did not work.
- GuardrailsGuardrails are the rules, filters, and technical limits placed around an AI system to keep its behavior within acceptable bounds, such as refusing harmful requests, staying on topic, protecting data, or requiring approval before acting.