ToolCallChunk

A chunk of a tool call (yielded when streaming).

When merging ToolCallChunk objects (e.g., via AIMessageChunk.__add__), all string attributes are concatenated. Chunks are only merged if their values of index are equal and not None.

Example:

left_chunks = [ToolCallChunk(name="foo", args='{"a":', index=0)]
right_chunks = [ToolCallChunk(name=None, args="1}", index=0)]

(
    AIMessageChunk(content="", tool_call_chunks=left_chunks)
    + AIMessageChunk(content="", tool_call_chunks=right_chunks)
).tool_call_chunks == [ToolCallChunk(name="foo", args='{"a":1}', index=0)]