# tinker_cookbook.renderers.TrainOnWhat

## _class_ [**tinker_cookbook.renderers.TrainOnWhat**](https://github.com/thinking-machines-lab/tinker-cookbook/blob/main/tinker_cookbook/renderers/base.py#L1250)( _StrEnum_)

Enum controlling which parts of the sequence to compute loss on.

**Members:**
- LAST_ASSISTANT_MESSAGE: Train only on the final assistant message.
- LAST_ASSISTANT_TURN: Train on the last assistant turn (including any tool calls and tool responses leading to the final assistant reply).
- ALL_ASSISTANT_MESSAGES: Train on every assistant message in the conversation.
- ALL_MESSAGES: Train on all messages regardless of role.
- ALL_TOKENS: Train on every token in the sequence (including special tokens).
- ALL_USER_AND_SYSTEM_MESSAGES: Train on user and system messages only.
- CUSTOMIZED: Use per-message `train` flags from the dataset.

## Referenced by

- [tinker_cookbook.renderers.Renderer.build_supervised_example](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/renderers/renderer/#renderer-build_supervised_example)
- [tinker_cookbook.renderers.Renderer.build_supervised_examples](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/renderers/renderer/#renderer-build_supervised_examples)
- [tinker_cookbook.supervised.ChatDatasetBuilderCommonConfig](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/supervised/chatdatasetbuildercommonconfig/)