10 principles for high-quality agent system prompts

10 principles

• 1. Clearly define role and boundaries ("you are a writing assistant, not legal counsel")
• 2. Enumerate available tools and when to call each
• 3. Add confirmation gates for destructive operations
• 4. Constrain reply format ("plan, then act, then 1-paragraph summary")
• 5. Provide 1-2 full example dialogues
• 6. State hard nos explicitly ("never force-push")
• 7. Ask the user when uncertain — do not guess
• 8. Fail-safes belong in the prompt ("stop after 3 tool failures and report")
• 9. Keep it under ~8K tokens; everything else is lower priority
• 10. Test, iterate, and version your prompt