System Prompts That Actually Work: A Field Guide
How to write the system prompt that governs your assistant, bot, or agent — with a tested template.
By AiClubb Team
A system prompt is the constitution of your AI application. It sets identity, scope, rules, and format for every turn. Writing one well is the difference between a useful assistant and a liability.
Start with identity: who the AI is and who it serves. Then scope — what it may and may not do. Then data rules — which sources to use for what. Then format and guardrails.
The most important section is the refusal logic. Define exactly when the bot must say "I do not know" instead of guessing. Hallucination is the leading cause of assistant failure.
Keep it under 1000 tokens. Every redundant rule dilutes the important ones. Test against angry, vague, and off-topic inputs — not just happy paths.
Version your system prompts like code. When you change policy, bump the version and re-test. Log real conversations to find where the prompt breaks.
Use our support-bot-system and moderator-system templates in the library as starting points. Adapt, test, and iterate.