We observed slightly smaller outputs over long horizon agentic coding for GPT 5.5, at a significant improvement in overall response scores. For one-shot coding

We observed slightly smaller outputs over long horizon agentic coding for GPT 5.5, at a significant improvement in overall response scores. For one-shot coding responses, GPT 5.5 was actually more verbose than GPT 5.4, but again, the responses were significantly stronger. The expected cost increases reported by OpenRouter seem reasonably accurate (perhaps a bit optimistic), but in my opinion, highly worth it. GPT 5.5 has a pretty wide lead on the #2 model for understanding complex scenarios. Rankings at https://gertlabs.com/rankings?mode=agentic_coding https://gertlabs.com/rankings?mode=agentic_coding. See the efficiency chart at the bottom.