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Add custom span-level attributes to a specific LangChain component’s metadata. Attributes are stored under the Fiddler metadata key on the component and read by FiddlerAgentMiddleware when creating spans. Unlike add_session_attributes(), these are scoped to individual components and only applied to spans created for that component (e.g. a particular model, retriever, or tool).

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Parameters

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node
BaseLanguageModel | BaseRetriever | BaseTool
required
The LangChain component to annotate (modified in place). Accepts BaseLanguageModel, BaseRetriever, or BaseTool instances.
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**kwargs
Any
Arbitrary key-value attributes. Keys matching known FiddlerSpanAttributes values are set directly; all others are prefixed with fiddler.span.user..

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Returns

None Example: default from langchain_openai import ChatOpenAI from fiddler_langchain import add_span_attributes llm = ChatOpenAI(model=“gpt-4o”) add_span_attributes(llm, model_tier=“premium”, use_case=“summarization”)