CallToolActivityEvent

One tool-activity event the voice platform observed during the call.

  • kind
    Type: enum
    required

    What the event records: a background task start, a tool request, a tool result, or a task end.

    values
    task_startedtool_calledtool_resulttask_finished
  • occurred_at
    Type: stringFormat: date-time
    required

    When the voice platform observed this event.

  • sequence
    Type: integer
    min:  
    0
    required

    The order of this event within the call, from 0.

  • invocation_id
    Type: stringnullable

    Ties a tool request to its result within this call. Present on tool_called and tool_result. It is not the tool_call_id your tool endpoint receives.

  • outcome
    Type: enumnullable

    How the tool or task ended. Null on tool_called and task_started.

    values
    returnederrortimeoutcancelled
  • payload_state
    Type: enum

    How much of the payload payload_text shows.

    values
    fullredactedtruncatedredacted_truncatedunavailable
  • payload_text
    Type: stringnullable

    A sanitized preview of the tool input, the tool result, the task instruction, or the task summary. Credential fields show as [redacted]. Null when no preview is available or the whole payload was withheld.

  • task_id
    Type: stringnullable

    The background task this event belongs to. Null for a tool that ran outside a background task.

  • tool_name
    Type: stringnullable

    The tool that was called. Present on tool_called and tool_result.

  • turn
    Type: integernullable

    The index of the last transcript turn before this event, when the call has no timed transcript. Null before the first turn.