LangChain Core 1.7 changes raw streamed tool-call arguments
LangChain released `langchain-core` 1.7.0 with raw tool-call arguments emitted as `tool-call-delta` slices instead of cumulative `block-delta` snapshots. Iterating `ChatModelStream.tool_calls` now yields each new argument slice; the higher-level `.tool_calls.get()` and `.output` interfaces remain unchanged.
Why it matters: Consumers that parse raw stream events can silently concatenate, display or validate tool arguments incorrectly after an upgrade. The change is narrow but breaking at a high-authority boundary: partial tool arguments often drive UI previews, policy checks…