System Prompt Builder
Build structured system prompts for any LLM — define role, rules, output format, tone, and few-shot examples. Export as plain text or JSON.
Complete the sentence: "You are …"
What the model should always do, and what it should never do.
No rules yet — click “+ Do” or “+ Don't” to add one.
Show the model the exact style and format of response you expect.
No examples yet — click “+ Add Example” to add a user/assistant pair.
## Tone Maintain a professional tone in all responses.
How to Use
Pick a preset or start blank
Choose a role preset (Customer Support, Code Reviewer, etc.) to pre-fill all fields instantly, or leave everything blank and build from scratch.
Fill in each section
Define the role, add behavior rules (Do / Don't), select output format and tone, and optionally add few-shot examples to show the model the style you expect.
Review the live preview
The assembled system prompt updates in real time as you type. Read it as a whole to make sure it flows naturally and covers your requirements.
Export your prompt
Copy as plain text to paste into a system prompt field, or copy as JSON for programmatic use in your application code or prompt-management pipeline.
FAQ
Have more questions? Contact us