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ChatFormatter for converting context histories to chat-message lists. ChatFormatter is the standard formatter used by mellea’s legacy backends. Its to_chat_messages method linearises a sequence of [Component](../core/base#class-component) and [CBlock](../core/base#class-cblock) objects into Message objects with user, assistant, or tool roles, handling [ModelOutputThunk](../core/base#class-modeloutputthunk) responses, image attachments, and parsed structured outputs. Concrete backends call this formatter when preparing input for a chat completion endpoint.

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Classes

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CLASS ChatFormatter

Formatter used by Legacy backends to format Contexts as Messages.
Methods:

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FUNC to_chat_messages 

to_chat_messages(self, cs: list[Component | CBlock]) -> list[Message]
Convert a linearized chat history into a list of chat messages. Iterates over each element in the context history and converts it to a Message with an appropriate role. [ModelOutputThunk](../core/base#class-modeloutputthunk) instances are treated as assistant responses, while all other [Component](../core/base#class-component) and [CBlock](../core/base#class-cblock) objects default to the user role. Image attachments and parsed structured outputs are handled transparently. Args:
  • cs: The linearized sequence of context components and code blocks to convert.
Returns:
  • list[Message]: A list of Message objects ready for submission to a chat completion endpoint.