Functions for converting messages into the various commonly used chat template formats.

Format examples

There are currently no industry standards around model's chat formats. For any given model, it's documentation and config may need to be inspected for it's format, and it may be something not supported at this time.

:inst

<s>[INST] System message. User message. [/INST]
Assistant response
[INST] User message. [/INST]</s>
Assistant response

Note: The :inst format has no concept of a system message. It will be combined with the first user message

:im_start

<|im_start|>user
User message.<|im_end|>
<|im_start|>assistant
Assistant response.<|im_end|>
<|im_start|>user
User message.<|im_end|>
<|im_start|>assistant

Note: The :im_start format has no concept of a system message. It will be combined with the first user message.

:llama_2

<s>[INST] <<SYS>>
System message.
<</SYS>>

User message [/INST] Assistant response </s><s>[INST] User message. [/INST]

Note: The :llama_2 format supports specific system messages. It is a variation of the :inst format.

:llama_3

<|begin_of_text|>
<|start_header_id|>system<|end_header_id|>

System message.<|eot_id|>
<|start_header_id|>user<|end_header_id|>

User message.<|eot_id|>
<|start_header_id|>assistant<|end_header_id|>

Assistant message.<|eot_id|>

:zephyr

<|system|>
System message.</s>
<|user|>
User message.</s>
<|assistant|>
Assistant message.
<|user|>
User message.</s>

Note: The :zephyr format supports specific system messages.

:phi_4

The :phi_4 template format is also supported.

Template callback

It's possible to pass a callback as a template. The function receives the list of messages as first argument and opts as second and must return a string.