Tag: prompt-cache

All the articles with the tag "prompt-cache".

• Same system prefix, zero cache hits on the branching path: debugging GPT-5.6 prompt caching

  25 Jul, 2026

  Two paths in the same agent send a byte-identical system prefix. The main conversation hits prompt cache; the other one is 0/24. After eliminating seven hypotheses, the answer was prompt_cache_breakpoint, plus an undocumented rule: the cache entry's matchable boundary ends before the last message.

• 共用同一段 system prefix,分支請求卻一次都沒命中:一次 GPT-5.6 prompt cache 排查

  25 Jul, 2026

  同一個 agent 裡兩條路徑送出位元完全相同的 system prefix,主對話吃得到 prompt cache,另一條 0/24 一次都沒中。排掉七個假設之後,答案是 prompt_cache_breakpoint,以及一條官方文件沒寫的規則:cache entry 的邊界落在最後一則訊息之前。