I'm surprised more people aren't talking about the cache hit price: $0.003 per million tokens. I have a feeling that the price of 1 million tokens transmitted over the internet is more expensive than cache hit. Are we close to making the chat completion API obsolete because the cost of context transfer over network is going to dominate the task total cost?
Here's the same token usage priced at different rates: a real long-running coding task, medium codebase, 447 turns.
Input 1,026,957
Output 164,667
Cache read 36,554,368
GPT-6-astra
Type Rate Cost Share
Input 10.000 10.270 19%
Output 50.000 8.233 15%
Cache 1.000 36.554 66%
Total 55.057 100%
DeepSeek v4.1 Flash, $0.003 cache hit
Type Rate Cost Share
Input 0.300 0.308 50%
Output 1.200 0.198 32%
Cache 0.003 0.110 18%
Total 0.615 100%
DeepSeek v4.1 Flash, $0.006 cache hit
Type Rate Cost Share
Input 0.300 0.308 42%
Output 1.200 0.198 27%
Cache 0.006 0.219 30%
Total 0.725 100%
Hypothetical: same DeepSeek input/output rates, but cache priced so it accounts for 66% of the bill.
Type Rate Cost Share
Input 0.300 0.308 21%
Output 1.200 0.198 13%
Cache 0.027 0.982 66%
Total 1.487 100%
This cache it improvement makes the model x2-x2.5 more efficient on a long horizon tasks in terms of cost.