Key Info

On Claude Opus 5.5, a cache hit costs $0.20 per million input tokens while a miss costs $4, a 20x difference. Because agents resend the entire conversation every turn, hit versus miss rates largely determine the bill.

Highlights

  • Cache hit price: $0.20 per million input tokens
  • Cache miss price: $4 per million input tokens
  • 20x cost difference between hit and miss
  • Agents resend full conversation context each turn, amplifying the impact
  • Understanding caching pricing and how to keep cache warm is key to controlling spend