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    Pythonlangchain-coretracersevent_stream_AstreamEventsCallbackHandleron_tool_start
    Methodā—Since v0.2

    on_tool_start

    Copy
    on_tool_start(
      self,
      serialized: dict[str, Any],
      input_str: str,
      *
    View source on GitHub
    ,
    run_id
    :
    UUID
    ,
    tags
    :
    list
    [
    str
    ]
    |
    None
    =
    None
    ,
    parent_run_id
    :
    UUID
    |
    None
    =
    None
    ,
    metadata
    :
    dict
    [
    str
    ,
    Any
    ]
    |
    None
    =
    None
    ,
    name
    :
    str
    |
    None
    =
    None
    ,
    inputs
    :
    dict
    [
    str
    ,
    Any
    ]
    |
    None
    =
    None
    ,
    **
    kwargs
    :
    Any
    =
    {
    }
    )
    ->
    None

    Start a trace for a tool run.