Hi @anthonyralston, from the dialo-gpt pape 2r, section 3.1

We first concatenate all dialog turns within a dialogue session into a long text x1, · · · , xN (N is the sequence length), ended by the end-of-text token.

So I think you won’t need to add eos  tokens. Just concatenate your history and feed it to the model. That is how the model is trained.