GitHub turned on the most expensive model in Copilot for you and didn't ask
by default, GPT-6 Astra switched on automatically on 4 September unless an admin had already disabled the global default.
so here're two rates worth knowing before someone runs a repo-wide agent task:
> $10 in, $50 out per million, double above 272K input
> cache write is a separate $12.50, which older OpenAI models never had
check out the full guide on Astra in the article below