Repeating a Prompt Rule Helps — But Only Up to Four Times

Say It Four Times (In Your System Prompt)

A developer tests the common advice to repeat important instructions in system prompts. Using Gemini 2.5 Flash, they measure how often the model obeys a rule about quote style across 1,080 runs. Results: one mention gives 74% compliance, four mentions 97%, and further repetitions add nothing. The post also reveals that many prompt tweaks are coin flips, and that the model may ignore constraints it files under a different category, like docstrings.