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Documentation Index

Fetch the complete documentation index at: https://handbook.fiddler.ai/llms.txt

Use this file to discover all available pages before exploring further.

What You’ll Learn

This interactive notebook demonstrates advanced monitoring patterns for production LangGraph applications through a realistic travel planning system with multiple specialized agents. Key Topics Covered:
  • Multi-agent workflow monitoring and orchestration
  • Custom instrumentation with decorators and span wrappers
  • Combining auto-instrumentation with fine-grained manual spans
  • Conversation tracking across complex interactions
  • Production configuration for high-volume scenarios
  • Advanced error handling and recovery patterns
  • Business intelligence integration and analytics

Interactive Tutorial

The notebook walks through building a comprehensive travel planning application featuring hotel search, weather analysis, itinerary planning, and supervisor agents working together. Open the Advanced Observability Notebook in Google Colab → Or download the notebook directly from GitHub →

Custom Instrumentation Tutorial

For hands-on examples of decorator-based and manual instrumentation, including @trace(), span wrappers, and async support: Open the Custom Instrumentation Notebook in Google Colab → Or download the notebook directly from GitHub →

Custom Instrumentation Patterns

The SDK supports three instrumentation approaches. You can use them individually or combine them in the same application. For complete API reference, see the Instrumentation Methods section in the integration guide.

Combining Auto-Instrumentation with Decorators

Use LangGraphInstrumentor for automatic LangGraph/LangChain tracing, then add @trace() decorators to capture custom business logic that runs outside the framework:
from fiddler_langgraph import FiddlerClient, LangGraphInstrumentor, trace, get_current_span

client = FiddlerClient(
    application_id="your-app-id",
    api_key="your-api-key",
    url="https://your-instance.fiddler.ai"
)

# Auto-instrument LangGraph nodes
instrumentor = LangGraphInstrumentor(client)
instrumentor.instrument()

# Add custom tracing to business logic outside LangGraph
@trace(name="validate_input", as_type="chain")
def validate_user_input(user_message: str) -> dict:
    span = get_current_span(as_type="chain")
    if span:
        span.set_input(user_message)

    result = {"valid": True, "sanitized": user_message.strip()}

    if span:
        span.set_output(result)
    return result

# Both auto-instrumented LangGraph spans and custom spans
# appear together in Fiddler's trace view
validated = validate_user_input(user_message)
result = agent.invoke({"messages": [{"role": "user", "content": validated["sanitized"]}]})

Multi-Agent Decorator Patterns

When building multi-agent systems, @trace() decorators automatically establish parent-child span relationships through nested function calls:
import asyncio
from fiddler_langgraph import trace, get_current_span

@trace(name="supervisor", as_type="chain")
async def supervisor_agent(state: dict) -> dict:
    """Top-level orchestrator — creates parent span."""
    span = get_current_span(as_type="chain")
    if span:
        span.set_attribute("agent_count", len(state.get("tasks", [])))

    # Child spans nest automatically under the supervisor span
    results = await asyncio.gather(
        research_agent(state),
        analysis_agent(state),
    )

    if span:
        span.set_output({"completed": len(results)})
    return {"results": results}

@trace(name="research_agent", as_type="chain")
async def research_agent(state: dict) -> dict:
    """Child span nested under supervisor."""
    span = get_current_span(as_type="chain")
    if span:
        span.set_attribute("data_sources", 3)
    # ... research logic ...
    return {"findings": "..."}

@trace(name="analysis_agent", as_type="chain")
async def analysis_agent(state: dict) -> dict:
    """Child span nested under supervisor."""
    span = get_current_span(as_type="chain")
    if span:
        span.set_attribute("analysis_type", "comparative")
    # ... analysis logic ...
    return {"analysis": "..."}

Using Span Wrappers for Typed Attributes

Span wrapper classes provide typed helper methods for setting semantic attributes on LLM calls, tool invocations, and chain operations. Use them with start_as_current_span() for fine-grained control:
from fiddler_langgraph import FiddlerClient

client = FiddlerClient(
    application_id="your-app-id",
    api_key="your-api-key",
    url="https://your-instance.fiddler.ai"
)

# as_type="generation" returns a FiddlerGeneration wrapper with LLM-specific helper methods
with client.start_as_current_span("llm_call", as_type="generation") as gen:
    gen.set_model("gpt-4o")
    gen.set_system_prompt("You are a travel planning assistant.")
    gen.set_user_prompt(user_input)

    response = call_llm(user_input)

    gen.set_completion(response.content)
    gen.set_usage(response.usage.prompt_tokens, response.usage.completion_tokens)

# as_type="tool" returns a FiddlerTool wrapper with tool-specific helper methods
with client.start_as_current_span("search_hotels", as_type="tool") as tool:
    tool.set_tool_name("hotel_search")
    tool.set_tool_input({"city": "Paris", "dates": "2026-03-01"})

    results = search_hotels("Paris", "2026-03-01")

    tool.set_tool_output(results)
For the complete list of helper methods on each span wrapper class, see the Span Types and Helper Methods reference.

Production Configuration Best Practices

Before deploying LangGraph applications to production, configure the SDK for your specific workload characteristics.

High-Volume Applications

Optimize for applications processing thousands of traces per minute:
import os
from opentelemetry.sdk.trace import SpanLimits, sampling
from opentelemetry.exporter.otlp.proto.http.trace_exporter import Compression
from fiddler_langgraph import FiddlerClient

# Configure batch processing BEFORE initializing FiddlerClient
os.environ['OTEL_BSP_MAX_QUEUE_SIZE'] = '500'         # Increased from default 100
os.environ['OTEL_BSP_SCHEDULE_DELAY_MILLIS'] = '500'  # Faster export than default 1000ms
os.environ['OTEL_BSP_MAX_EXPORT_BATCH_SIZE'] = '50'   # Larger batches than default 10
os.environ['OTEL_BSP_EXPORT_TIMEOUT'] = '10000'       # Longer timeout than default 5000ms

# Increase span limits to capture more data
production_limits = SpanLimits(
    max_events=128,                   # Default: 32
    max_links=64,                     # Default: 32
    max_span_attributes=128,          # Default: 32
    max_event_attributes=64,          # Default: 32
    max_link_attributes=32,           # Default: 32
    max_span_attribute_length=8192,   # Default: 2048
)

# Sample 5-10% of traces to manage data volume
production_sampler = sampling.TraceIdRatioBased(0.05)

client = FiddlerClient(
    application_id=os.getenv("FIDDLER_APPLICATION_ID"),
    api_key=os.getenv("FIDDLER_API_KEY"),
    url=os.getenv("FIDDLER_URL"),
    span_limits=production_limits,
    sampler=production_sampler,
    compression=Compression.Gzip,
)

Low-Latency Requirements

Optimize for applications requiring sub-second trace export:
import os
from opentelemetry.exporter.otlp.proto.http.trace_exporter import Compression
from fiddler_langgraph import FiddlerClient

# Reduce batch delay for faster exports
os.environ['OTEL_BSP_SCHEDULE_DELAY_MILLIS'] = '100'  # Export every 100ms
os.environ['OTEL_BSP_MAX_EXPORT_BATCH_SIZE'] = '5'    # Smaller batches

client = FiddlerClient(
    application_id=os.getenv("FIDDLER_APPLICATION_ID"),
    api_key=os.getenv("FIDDLER_API_KEY"),
    url=os.getenv("FIDDLER_URL"),
    compression=Compression.Gzip,  # Still use compression
)

Memory-Constrained Environments

Configure conservative limits for edge deployments or containerized environments:
import os
from opentelemetry.sdk.trace import SpanLimits, sampling
from opentelemetry.exporter.otlp.proto.http.trace_exporter import Compression
from fiddler_langgraph import FiddlerClient

memory_constrained_limits = SpanLimits(
    max_events=16,                  # Minimal event capture
    max_links=16,                   # Minimal linking
    max_span_attributes=32,         # Reduced attributes
    max_event_attributes=16,        # Reduced event attributes
    max_link_attributes=16,         # Reduced link attributes
    max_span_attribute_length=1024, # Shorter attribute values
)

os.environ['OTEL_BSP_MAX_QUEUE_SIZE'] = '50'           # Smaller queue
os.environ['OTEL_BSP_MAX_EXPORT_BATCH_SIZE'] = '5'    # Smaller batches

client = FiddlerClient(
    application_id=os.getenv("FIDDLER_APPLICATION_ID"),
    api_key=os.getenv("FIDDLER_API_KEY"),
    url=os.getenv("FIDDLER_URL"),
    span_limits=memory_constrained_limits,
    sampler=sampling.TraceIdRatioBased(0.1),  # Sample 10%
    compression=Compression.Gzip,
)

Development vs Production Configurations

Development Configuration:
import os
from fiddler_langgraph import FiddlerClient

# Capture everything with verbose debugging
# console_tracer=True prints spans to stdout AND continues to export to Fiddler (additive)
dev_client = FiddlerClient(
    application_id=os.getenv("FIDDLER_APPLICATION_ID"),
    api_key=os.getenv("FIDDLER_API_KEY"),
    url=os.getenv("FIDDLER_URL"),
    console_tracer=True,    # Also prints spans to console; does NOT disable OTLP export
    sampler=None,           # Capture 100% of traces
)
Production Configuration:
import os
from opentelemetry.sdk.trace import SpanLimits, sampling
from opentelemetry.exporter.otlp.proto.http.trace_exporter import Compression
from fiddler_langgraph import FiddlerClient

# Define production limits (see High-Volume Applications above for full example)
production_limits = SpanLimits(
    max_events=128, max_span_attributes=128, max_span_attribute_length=8192
)

# Optimized for performance and cost
prod_client = FiddlerClient(
    application_id=os.getenv("FIDDLER_APPLICATION_ID"),
    api_key=os.getenv("FIDDLER_API_KEY"),
    url=os.getenv("FIDDLER_URL"),
    sampler=sampling.TraceIdRatioBased(0.05),  # Sample 5%
    compression=Compression.Gzip,              # Reduce bandwidth
    span_limits=production_limits,             # Controlled limits
)

Best Practices for Context and Conversation IDs

Structure your identifiers for maximum analytical value:
from fiddler_langgraph import set_llm_context, set_conversation_id
import uuid

# Set meaningful, searchable context labels
set_llm_context(model, 'Customer Support - Tier 1 - Billing Inquiries')
set_llm_context(model, 'Content Generation - Marketing Copy - Blog Posts')
set_llm_context(model, 'Data Analysis - Financial Reports - Q4 2025')

# Use structured conversation IDs with metadata
user_id = 'user-12345'
session_type = 'support'
timestamp = '2026-06-15'
conversation_id = f'{user_id}_{session_type}_{timestamp}_{uuid.uuid4()}'
set_conversation_id(conversation_id)

# Example: user-12345_support_2026-06-15_550e8400-e29b-41d4-a716-446655440000

Prerequisites

  • Fiddler account with API credentials
  • OpenAI API key for example interactions
  • Basic familiarity with LangGraph concepts

Time Required

  • Complete tutorial: 45-60 minutes
  • Quick overview: 15-20 minutes

Telemetry Data Reference

Understanding the data captured by the Fiddler LangGraph SDK.

Span Attributes

The SDK automatically captures these OpenTelemetry attributes:
AttributeTypeDescription
gen_ai.agent.namestrName of the AI agent (auto-extracted from LangGraph, configurable for LangChain)
gen_ai.agent.idstrUnique identifier (format: trace_id:agent_name)
gen_ai.conversation.idstrSession identifier set via set_conversation_id()
fiddler.span.typestrSpan classification: chain, tool, llm, or agent
gen_ai.llm.input.systemstrSystem prompt content
gen_ai.llm.input.userstrUser input/prompt
gen_ai.llm.outputstrModel response text
gen_ai.llm.contextstrCustom context set via set_llm_context()
gen_ai.request.modelstrModel identifier (e.g., “gpt-4o-mini”)
gen_ai.llm.token_countintToken usage metrics
gen_ai.tool.namestrTool function name
gen_ai.tool.inputstrTool input parameters (JSON)
gen_ai.tool.outputstrTool execution results (JSON)
gen_ai.tool.definitionsstrTool definitions available to the LLM (JSON array of OpenAI-format tool schemas)
gen_ai.input.messagesstrComplete message history provided as input to the LLM (JSON array)
gen_ai.output.messagesstrOutput messages generated by the LLM, including tool calls (JSON array)
duration_msfloatSpan duration in milliseconds
fiddler.error.messagestrError message (if span failed)
fiddler.error.typestrError type classification

Setting Attributes with Span Wrappers

When using manual instrumentation, span wrapper classes provide typed helper methods that set these attributes automatically. For example, FiddlerGeneration.set_model("gpt-4o") sets gen_ai.request.model, and FiddlerTool.set_tool_name("search") sets gen_ai.tool.name.
Span WrapperKey MethodsAttributes Set
FiddlerGenerationset_model(), set_system_prompt(), set_user_prompt(), set_completion(), set_usage(), set_messages(), set_output_messages(), set_tool_definitions()gen_ai.request.model, gen_ai.llm.input.*, gen_ai.llm.output, gen_ai.usage.*, gen_ai.input.messages, gen_ai.output.messages, gen_ai.tool.definitions
FiddlerToolset_tool_name(), set_tool_input(), set_tool_output(), set_tool_definitions()gen_ai.tool.name, gen_ai.tool.input, gen_ai.tool.output, gen_ai.tool.definitions
FiddlerChainset_input(), set_output()Input/output data attributes
FiddlerSpanset_attribute(), set_agent_name(), set_conversation_id()Any custom or standard attribute
For the complete method reference, see Span Types and Helper Methods.

Querying and Filtering in Fiddler

Use these attributes in the Fiddler UI to:
  • Filter by agent: gen_ai.agent.name = "hotel_search_agent"
  • Find conversations: gen_ai.conversation.id = "user-123_support_2026-06-15..."
  • Analyze by model: gen_ai.request.model = "gpt-4o"
  • Track errors: fiddler.error.type EXISTS

Who Should Use This

  • AI engineers building production LangGraph applications
  • DevOps teams monitoring agentic systems
  • Technical leaders evaluating observability strategies

Limitations and Considerations

Current Limitations

  • Framework Support: LangGraph is fully supported with automatic agent name extraction
    • LangChain applications require manual agent name configuration
    • Non-LangGraph Python code can use @trace() decorators or manual context managers for custom instrumentation (see Instrumentation Methods)
  • Protocol Support: Currently uses HTTP-based OTLP
    • gRPC support planned for future releases
  • Attribute Limits: Default OpenTelemetry limits apply
    • Configurable via span_limits parameter
    • Very large attribute values may be truncated

Performance Considerations

Overhead: Typical performance impact is < 5% with default settings
  • Use sampling to reduce overhead in high-volume scenarios
  • Adjust batch processing delays based on latency requirements
Memory: Span queue size affects the memory footprint
  • Default queue (100 spans) uses ~1-2MB
  • Increase OTEL_BSP_MAX_QUEUE_SIZE for high throughput
  • Decrease for memory-constrained environments
Network: Compression significantly reduces bandwidth usage
  • Gzip compression: ~70-80% reduction
  • Use Compression.NoCompression only for debugging

Production Deployment Checklist

Before deploying to production:
  • Set appropriate sampling rate (typically 5-10% for high-volume apps)
  • Configure span limits based on your data characteristics
  • Tune batch processing parameters for your traffic patterns
  • Enable Gzip compression (default, recommended)
  • Use environment variables for credentials (not hardcoded)
  • Test instrumentation in staging environment first
  • Monitor SDK performance impact
  • Set up alerts for instrumentation failures
  • Document your configuration for team knowledge sharing

When to Tune Each Setting

ScenarioConfiguration
High-volume productionIncrease queue size, batch size, sampling rate
Low-latency requirementsDecrease schedule delay, smaller batches
Memory constraintsDecrease span limits, queue size, batch size
Development/debuggingDisable sampling, enable console tracer
Cost optimizationIncrease sampling (lower %), enable compression

Next Steps

After completing the tutorial: