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ChatMessage

A single message in a chat conversation.

roleRole (string)required

Message role: 'user', 'assistant', 'system', or 'tool'

content object

Message content. Usually a string, but may be a multimodal content list (e.g. text + image_url) or null for assistant turns that only request tool calls.

anyOf
tool_call_id object

For tool messages, the ID of the tool call

anyOf
string
name object

For tool messages, the tool name

anyOf
string
tool_calls object

For assistant messages replayed from prior turns, the OpenAI-format tool calls the model previously requested. Replaying these verbatim keeps the conversation prefix byte-for-byte identical so the model server's prompt cache hits on follow-up turns.

anyOf
  • Array [
    • object
  • ]
    • ChatMessage
    {
      "role": "string",
      "tool_call_id": "string",
      "name": "string",
      "tool_calls": [
        {}
      ]
    }