OpenAI launched an improved prompt caching system for the GPT-6 family that delivers higher cache hit rates by default. Developers get discounts of up to 90% on cached input tokens when the system reuses shared prefixes within a 30-minute window. New tools include a Prompt Caching Dashboard to track hit rates and a diagnostics tool to investigate unexpected misses. Developers can also prewarm the cache to reduce latency or adjust reasoning effort between responses without breaking cache.