# Special Tokens + ChatML + Chat Templates: Tokenization Anatomy of the Conversational LLM

> Source: https://sukruyusufkaya.com/en/learn/llm-muhendisligi/special-tokens-chatml-chat-templates
> Updated: 2026-05-13T13:00:26.556Z
> Category: LLM Mühendisliği
> Module: Module 6: Tokenization Microsurgery
**TLDR:** Birth of chat formats (ChatGPT March 2022), ChatML spec, anatomy of <|im_start|>/<|im_end|>/<|im_sep|> tokens, Llama-3 Instruct + Mistral [INST] + Claude Messages API + Gemini formats, HuggingFace chat_template Jinja2, system prompt placement, tool use tokens, prompt injection security, multi-turn token economy, Turkish chat practice.