OpenAI Tokenizer
Interestingly they seem to have different token ids for "Word", "word", " Word" and " word". That seems kind of a wasteful design.It seems like it would make more sense to have a single token for all variants and then a "capitalized where not expected" token (e.g. "foo Foo"), a "not capitalized where expected" token (e.g. "foo. foo") and a "missing space where expected" token (e.g. "foo.Foo").The lack of any normalization also means that WrItInG tExT lIkE tHiS will make future GPT versions not be able to make full use of the text during future training unless they change the tokenization (or the model is so overpowered that it doesn't matter).