fix(langgraph): keep the tool call that starts on the chunk ending streamed text - #2607
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itsklimov wants to merge 1 commit into
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fix(langgraph): keep the tool call that starts on the chunk ending streamed text#2607itsklimov wants to merge 1 commit into
itsklimov wants to merge 1 commit into
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…reamed text When a model streams text and then a tool call inside the same assistant message (Anthropic emits the tool_use block right after the text block), the OnChatModelStream handler ended the text message and returned. The tool call's start and every argument chunk were dropped: it never reached the client unless a later on_tool_end re-emitted it, which does not happen for tool calls handled outside a ToolNode. Fall through to the tool-call start after ending the text, matching the Python adapter.
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Fixes #2606
Problem
When a model streams text and then a tool call inside the same assistant message (Anthropic emits the
tool_useblock right after thetextblock), theOnChatModelStreamhandler ended the text message and returned. The tool call's start and every argument chunk were dropped. AToolNodetool was re-emitted whole onon_tool_end; a tool call handled outside aToolNode(frontend tools, the injected A2UI render tool) never reached the client.Fix
After
TEXT_MESSAGE_END, fall through to the tool-call start when the chunk carries a named tool call. Same behaviour as the Python adapter. Oneconstbecameletfor that.Adds
text-then-tool-call.test.tswith the Anthropic chunk sequence; it fails onmainand passes with the fix. The rest of the package suite passes.Changes written by Claude Fable 5.1 in Claude Code, reviewed by the submitter.