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System prompt generator

A system prompt tells an assistant who it is and how to behave in every chat. Say what yours should do and our AI writes the whole thing: role, rules, what to avoid and how to reply.

Free tool · Updated

Where it will run
Tone
Describe what you want first, then tap Make my prompt.

How to use it

  1. Write the assistant's job in one line, like “answer customer questions for my yoga studio”.
  2. Pick where it will run: a custom GPT, Claude Project, Gemini Gem, website chatbot or agent.
  3. Pick a tone if it matters.
  4. Tap Make my prompt, log in with one click, and paste the result into your assistant's instructions.

Tips

  • Say who the users are. An assistant for beginners should sound different from one for experts.
  • Tell it what to do when it doesn't know. “Say so and suggest who to ask” beats a made-up answer.
  • Fill in any [INSERT …] fields with your real details, like opening hours or prices.
  • Test it with three awkward questions before you share it.

Frequently asked questions

What is a system prompt?

The standing instructions an AI assistant reads before every conversation. It sets the role, tone, rules and reply format, so users don't have to repeat them.

Where do I paste the system prompt?

In a custom GPT, the Instructions box. In a Claude Project, the project instructions. In a Gemini Gem, the Gem's instructions. For an API or chatbot, the system message.

How long should a system prompt be?

Long enough to cover the job, the audience, the rules and the format. For most assistants that's a few short paragraphs and some bullets.

Is it free?

Yes. A free PromptItIn account writes the system prompt, no card needed.

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Want a full prompt, not just keywords?

PromptItIn turns a rough idea into a clear prompt for ChatGPT, Claude, Gemini or any image model. Free to start.

Open the prompt generatorAdd to Chrome, free