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Glossary: Fine-tuning LLMs

Special tokens

Also written: <|im_start|>, special token

Reserved tokens such as `<|im_start|>` and `<|im_end|>` that mark where each turn begins and ends. The chat template inserts them, so the model trains on them.

Where the book teaches it

Related terms

Chat templateEnd-of-sequence (EOS) tokenChatML