@langchain/core@1.2.18

Patch Changes

• #11956 93d62b0 Thanks @hntrl! - Require langsmith >=0.11.0 to include the restored NullableHeaders type declarations.

• #11822 d3e6fe6 Thanks @dqbd! - Add explicit agent address support to LangChainTracer, inherit project and address destinations together, and delegate default destination resolution to the LangSmith SDK.

• #11150 cea15cf Thanks @mdnanocom! - fix(core): defer tool call chunk collapsing in AIMessageChunk to fix O(n²) streaming aggregation

  AIMessageChunk eagerly re-ran collapseToolCallChunks in its constructor on every streamed delta concat, re-parsing all accumulated tool args each time — O(n²) over a stream, which can block the event loop for seconds on long tool-call streams. Collapsing now runs lazily, once, on first read of tool_calls / invalid_tool_calls.