This page:-
https://platform.openai.com/docs/models/tts#default-usage-policies-by-endpoint
says, in regards to data retention on /v1/batches:
“Until deleted by customer”
However, none of the standard “delete” operations are functional (all return errors), and the API guide for batches https://platform.openai.com/docs/guides/batch does not reveal any options to delete.
My list of completed batches is growing out-of-control now, and I’m eager to remove them…