I can't understand why your T would react like this. If she didn't think it was helpful I would expect a T to very gently explain why not. I think T's should know that they need to handle saying no to a client really sensitively as that can spark a big emotional reaction. I don't know why she thinks this is a boundary crossing, seems like a good idea to me. I too would like to ask my new T to write something to help me between sessions. Once they see that a client is dissociating and having an emotional reaction I would expect a T to give reassurance and support to the client, and to be careful about the ending of a session when the client is clearly not ok (maybe even apologise? 'I'm sorry I can see that the way I said that was difficult for you'? Have you been seeing her for long? Is it the kind of relationship where you can discuss these things - is she receptive to that? Your description of your T reminds me of my ex-T. My ex-T seemed to have no self awareness of how her behaviour impacted on me.