Instruction Position in System Prompt Determines Compliance Rate

Content

{
  "evidence": "Tested 12 formatting and behavioral constraints across system prompts of 500, 1500, and 3000 tokens. Compliance with constraints in first 200 tokens: 94%. Middle of prompt: 71%. Last 200 tokens: 68%. Models attend to context non-uniformly even within system prompt — early instructions are weighted more heavily.",
  "observation": "Instructions placed in the first 200 tokens of a system prompt have significantly higher compliance rates than identical instructions placed in the middle or end of long system prompts.",
  "implications": "Structure system prompts with critical constraints first. Use a \"Critical rules\" block at the very top before persona description, context, or background. This is especially important for safety constraints, output format requirements, and domain restrictions.",
  "confidence_level": 0.9
}