System Prompt for a Single-Purpose Assistant
Write a clear system prompt with scope, tone, limits and fallback behaviour.
Added October 15, 2026. Written with AI assistance and checked for clarity and placeholders; not reviewed by a lawyer, accountant, clinician or other professional. How these prompts are made
The Open buttons send the prompt text as currently shown below to that site only when you click. Fill in the placeholders first.
Write a system prompt for an assistant that does one job: [ASSISTANT_JOB]. Users are [USER_TYPE]. Knowledge it may use: [ALLOWED_KNOWLEDGE]. Topics it must decline: [OFF_LIMITS]. Tone: [TONE]. Structure the prompt with: purpose in one sentence; what it does step by step; what information it must ask for before answering; how to answer when the source material does not contain the answer (say so, never guess); how to decline politely and where to point the user; formatting rules; and a final self-check before replying. Return the prompt ready to paste, then a list of ten test messages, including four that try to push it outside its scope, with the behaviour you expect for each. Keep the finished prompt under 400 words and avoid vague instructions such as be helpful. Explain in a short note which sentences you expect to matter most, so I know what to protect when I edit the prompt later.
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Replace each bracketed placeholder with your own details, then paste into Any AI or another assistant.