12-hour prompt caching option added to the API

Developers can now choose 12-hour prompt caching, which keeps shared instructions, tools and context cached longer so requests hours apart still get cached-input pricing. 12-hour cache writes cost 2.5 times the input token price.

Who is affected:

API apps with repeated prompts spaced hours apart.

What to do:

Compare 12-hour cache write costs against your cache hit rate before switching.