Type Alias ChatCompletionMessage

Content of the message, can be any string

The turn's reasoning blocks in replayable form (see ChatReasoningBlock). thinking above is the readable text; this is what the driver needs to send the turn back. Copy it onto the ChatMessage that replays this turn. Absent when the driver keeps none.

Role of the message in the conversation. For completions, this is always 'assistant'.

When using a reasoning model, this field can contain the reasoning behind the response. Not all providers/models support this field.

Tool calls the model made on this turn, normalized across providers. Absent or empty when the model did not call a tool.

A turn can carry BOTH content and toolCalls — the tool-capable providers structurally allow it (Anthropic text + tool_use blocks, OpenAI nullable content alongside tool_calls, Gemini text + functionCall parts) — so this is never an either/or with content. Equally, nothing downstream may assume content is non-empty on a tool-call turn: a forced ChatToolChoice usually suppresses text entirely.