Description
Prompt caching works correctly on Sonnet 4.5 and Opus 4.1, but is completely bypassed on Opus 4.5 and Haiku 4.5. The cache_control JSON and request structure are identical across all models.
Steps to reproduce
Tested with a sequence of API calls using the same cached content:
Sonnet 4.5 call: creates cache ✓
Opus 4.5 call: no cache read, no cache write
Haiku 4.5 call: no cache read, no cache write
Sonnet 4.5 call: reads from cache created in call 1 ✓
Opus 4.5 and Haiku 4.5 act as if the cache_control headers don't exist. They don't read, write, or invalidate the cache.
Expected behavior
All models should read from and write to the prompt cache when cache_control is specified, as Sonnet 4.5 and Opus 4.1 do.
Additional context
I reported the Haiku 4.5 issue previously and provided request IDs when asked, but never received follow-up. Opus 4.5 has now shipped with the same behavior.
Happy to provide request IDs again if needed.
Description
Prompt caching works correctly on Sonnet 4.5 and Opus 4.1, but is completely bypassed on Opus 4.5 and Haiku 4.5. The cache_control JSON and request structure are identical across all models.
Steps to reproduce
Tested with a sequence of API calls using the same cached content:
Sonnet 4.5 call: creates cache ✓
Opus 4.5 call: no cache read, no cache write
Haiku 4.5 call: no cache read, no cache write
Sonnet 4.5 call: reads from cache created in call 1 ✓
Opus 4.5 and Haiku 4.5 act as if the cache_control headers don't exist. They don't read, write, or invalidate the cache.
Expected behavior
All models should read from and write to the prompt cache when cache_control is specified, as Sonnet 4.5 and Opus 4.1 do.
Additional context
I reported the Haiku 4.5 issue previously and provided request IDs when asked, but never received follow-up. Opus 4.5 has now shipped with the same behavior.
Happy to provide request IDs again if needed.