Overview
Complete API reference documentation for thefiddler-otel package, the
framework-agnostic OpenTelemetry-based instrumentation layer for any
Python LLM or agent application. fiddler-otel is the canonical source
for Fiddler’s span attributes, conversation tracking, and span processing
primitives; the LangChain, LangGraph, and Strands SDKs build on top of it
and re-export several of its symbols.
Components
Attributes
Span and resource attribute helpers.set_conversation_id and add_session_attributes are propagated through the current trace context; FiddlerSpanAttributes, FiddlerResourceAttributes, and SpanType enumerate the constant keys Fiddler recognizes.
Client
Client initialization and configuration.FiddlerClient wires the OTLP exporter, span processor, and resource attributes into the global tracer provider; get_client returns the active singleton.
Decorators
Function-level tracing helpers.@trace instruments arbitrary Python functions; get_current_span returns the active span for attribute mutation inside a traced call.
JSONL Capture
JSONL span exporter for offline analysis. Writes a structured trace record per span to a local file alongside (or instead of) OTLP export, useful for debugging and reproducing customer issues.Span Processor
Custom OpenTelemetry span processor that enriches outgoing spans with Fiddler resource attributes before export.Span Wrapper
Manual span creation primitives for code paths that don’t fit the decorator model.FiddlerSpan is the base; FiddlerChain, FiddlerGeneration, and FiddlerTool carry semantic conventions for retrieval/agent steps, LLM calls, and tool invocations.