library · inferred from evidence
langchain-core
A core library for LangChain, with a version requirement for the fix.
- ValueError: create_tool_calling_agent requires .bind_tools on the LLM when using with_fallbacks
The root cause: with_fallbacks wraps the model in a Runnable that hid bind_tools, so the agent factory could not find the method. A maintainer linked the fix in PR #22139, which forwards bind_tools through fallbacks: upgrade to langchain-co
- Error in RootListenersTracer.on_chain_end callback: KeyError('answer') while streaming a RAG chain
This warning is non-fatal: the streamed output is unaffected, only the tracing callback hits the missing key. Multiple reporters confirmed it went away after upgrading (langchain 0.2.14 / langchain-core 0.2.32 or later), so upgrading is the