The content blocks of this history item.
The key of the currently-active element instance.
OptionaliterationSequential iteration number this item belongs to. Omit if not grouping items into iterations.
The key of the current job activation during which this history item was produced.
Opaque lease token received from the job activation response.
OptionalmetricsPer-call token and latency metrics. Present on ASSISTANT items only.
The connector-side timestamp of when this message was produced.
The role of this history item in the conversation.
OptionaltoolTool calls associated with this history item. For ASSISTANT items: tool calls dispatched by this LLM response, with arguments populated. For TOOL_RESULT items: single-entry array referencing the originating tool call, with arguments null. Omit for USER items.
Request to append a single history item to an agent instance's conversation history.