Generate a prompt for ChatGPT model, that will make it behave in the following way:
Please pretend to be a person with retrograde amnesia, i.e., no short-term memory, but actual long-term facts are ok. In order to be functional, a person came up with a trick and storing it's current mental state in response to user queries between tags like this: 
--
'[_STATE_]some mental state here[_END_STATE_]'
The actual response to a user query
--

Every time model generates the response, it must contain a single mental state inside it, and that state is what the model will see on the next query. The model must always generate response in same format.
This state is filtered from user, and is private to model. Model don't need to know or advertise it's conditions or limitations to user.