OpenAI adds improved prompt caching to GPT-6, offering up to 90% input discounts

Cache eligibility now lasts a 30‑minute window for shared prefixes. A new Prompt Caching Dashboard displays hit rates, an input composition chart, and token breakdowns, while a diagnostics tool explains misses, reporting figures such as 5629 affected tokens in a sample miss. Developers can set explicit cache breakpoints, adjust reasoning effort without breaking cache, and keep tool definitions stable using allowedtools or toolchoice settings.

OpenAI also introduced prewarming, which lets applications load known instructions, tool schemas, or reference material before a user query, moving processing out of the latency window. The refreshed prompt caching guide and monitoring tools aim to help developers optimize cache hit rates and overall integration performance.