System Prompt Generator
Describe what you want your AI assistant to do — get a production-ready system prompt with role, constraints, output format, and guardrails.
Try an example:
Tell the AI exactly who it is and what its primary job is.
Specify what the AI must never do — this prevents hallucinations and off-topic responses.
Define how responses should be structured — length, tone, bullet points vs prose.
Tell the AI what to do when it gets unclear or out-of-scope requests.
What is a system prompt?
A system prompt is the hidden instruction you give an AI before the conversation starts. It defines who the AI is, what it does, how it responds, and what it must never do. Without a good system prompt, AI assistants give generic, inconsistent answers. With one, they behave like a purpose-built tool.
System prompts are used in ChatGPT Custom GPTs, Claude Projects, API integrations, customer support bots, internal tools, and any AI assistant you build or configure.
What each style produces
🔒 Strict
Tight rules, explicit constraints, minimal room for interpretation. Best for customer-facing bots, compliance-sensitive tools, or any assistant where consistency matters more than creativity.
⚖️ Balanced
Clear instructions with some flexibility. The AI follows your rules but can use judgment on edge cases. Best for most general-purpose assistants and internal tools.
🎨 Creative
Open-ended guidance that encourages the AI to explore, personalise, and adapt. Best for writing assistants, brainstorming tools, and creative applications.
Frequently asked questions
Where do I paste the system prompt?
In ChatGPT: Settings → Custom Instructions or the GPT builder. In Claude: Projects → Project Instructions. In the API: the "system" field of your request. In Gemini: the "System instructions" field.
How long should a system prompt be?
Shorter is usually better. A focused 200-400 word system prompt outperforms a 2000-word one because the AI can follow concise instructions more reliably. This tool targets that range.
Can I edit the generated prompt?
Yes — and you should. The generated prompt is a production-ready starting point. Add any domain-specific rules, examples, or constraints that are unique to your use case.
Does this work for all AI models?
Yes. The generated prompts follow universal best practices that work with ChatGPT, Claude, Gemini, Llama, and any other model that supports system prompts.