# Introduction

[![PyPI](https://img.shields.io/pypi/v/fiddler-otel)](https://pypi.org/project/fiddler-otel/)

## Overview

Complete API reference documentation for the `fiddler-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.

```bash
pip install fiddler-otel
```

```python
from fiddler_otel import FiddlerClient, trace
```

## 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.

* [add\_session\_attributes](/api/fiddler-otel-sdk/attributes/add-session-attributes.md)
* [FiddlerResourceAttributes](/api/fiddler-otel-sdk/attributes/fiddler-resource-attributes.md)
* [FiddlerSpanAttributes](/api/fiddler-otel-sdk/attributes/fiddler-span-attributes.md)
* [set\_conversation\_id](/api/fiddler-otel-sdk/attributes/set-conversation-id.md)
* [SpanType](/api/fiddler-otel-sdk/attributes/span-type.md)

### 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.

* [FiddlerClient](/api/fiddler-otel-sdk/client/fiddler-client.md)
* [get\_client](/api/fiddler-otel-sdk/client/get-client.md)

### Decorators

Function-level tracing helpers. `@trace` instruments arbitrary Python functions; `get_current_span` returns the active span for attribute mutation inside a traced call.

* [get\_current\_span](/api/fiddler-otel-sdk/decorators/get-current-span.md)
* [trace](/api/fiddler-otel-sdk/decorators/trace.md)

### 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.

* [JSONLSpanExporter](/api/fiddler-otel-sdk/jsonl-span-exporter.md)

### Span Processor

Custom OpenTelemetry span processor that enriches outgoing spans with Fiddler resource attributes before export.

* [FiddlerSpanProcessor](/api/fiddler-otel-sdk/fiddler-span-processor.md)

### 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.

* [FiddlerChain](/api/fiddler-otel-sdk/span-wrapper/fiddler-chain.md)
* [FiddlerGeneration](/api/fiddler-otel-sdk/span-wrapper/fiddler-generation.md)
* [FiddlerSpan](/api/fiddler-otel-sdk/span-wrapper/fiddler-span.md)
* [FiddlerTool](/api/fiddler-otel-sdk/span-wrapper/fiddler-tool.md)


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