YOU CAN'T EVAL GPT5 ANYMORE

Summary from the TLDR AI newsletter

The GPT-5 API is aware of the date, which is problematic because the model becomes aware that it is in a simulation when evals are run against it. There is evidence that models behave differently when they know they are in a simulation. Some models start questioning other parts of the simulation once they know they are in a simulation. The API being aware of the date may be an attempt at patching a safety risk.