What is a system prompt?

A system prompt is a set of instructions given to an AI model before any user interaction. It defines the AI's role, behaviour rules, expertise areas, output format, and constraints — shaping how the model responds to every subsequent message.

How do I write a good system prompt?

A good system prompt clearly defines the AI's role (e.g., "You are a senior software engineer"), lists specific expertise areas, sets behaviour rules (like "always cite sources"), specifies the output format (Markdown, JSON, etc.), and includes any constraints such as language or topics to avoid.

Do system prompts work with ChatGPT, Claude, and Gemini?

Yes. System prompts are supported by all major LLMs including OpenAI's ChatGPT (GPT-4o), Anthropic's Claude, Google's Gemini, DeepSeek, Llama, and Mistral. The format generated by this tool is compatible with all of them.

Is this system prompt generator free?

Yes, the System Prompt Generator is 100% free with no signup required. Build unlimited system prompts directly in your browser and copy them to use in any AI platform.

AI Prompt Architect

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Free System Prompt Generator

Build professional system prompts for ChatGPT, Claude, and Gemini — step by step

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Role

What role should the AI take on?

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Expertise

Type + Enter to add tags, or click suggestions below

+ React+ Python+ SQL+ Marketing+ Legal+ Healthcare+ TypeScript+ AWS

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Behaviour Rules

Select rules the AI must follow

Always cite sources

Use code blocks for code

Be concise

Ask clarifying questions

Think step by step

Avoid jargon

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Output Format

How should the AI format its responses?

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Constraints

Set limits and boundaries

Max response length

Language

Topics to avoid

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Tone

What tone should the AI use?

📋 Live Preview

0 chars

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