Challenge 04 - Custom Instrumentation with OpenTelemetry

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Introduction

In Challenge 03, you verified that the Agent Framework automatically generates traces and metrics for your AI agent operations. Now it’s time to add custom instrumentation to capture application-specific insights.

Custom instrumentation allows you to:

• Create spans for specific business operations (e.g., “plan_trip”, “validate_itinerary”)
• Record custom metrics (e.g., number of destinations, planning duration)
• Add structured logging context for better debugging
• Correlate application events with AI agent activities

By the end of this challenge, you’ll have visibility into both the automatic Agent Framework telemetry and your custom business logic, all flowing to New Relic.

Description

Your goal is to add custom spans, metrics, and structured logging to your travel planning application:

• Add Custom Spans - Instrument tool calls and business logic with manual spans
• Add Custom Metrics - Record meaningful measurements (trip planning duration, destination counts, etc.)
• Add Structured Logging - Correlate logs with spans using trace context
• Verify in New Relic - Confirm custom telemetry appears alongside auto-generated signals

What You’re Adding

Tool Instrumentation:

By leveraging the above approach you will notice that the Agent Framework automatically instruments tool calls. However, to get more detailed insights, you will manually add spans around each tool function:

• Get a tracer for creating spans
• Wrap each tool function (get_random_destination, get_weather, get_datetime) with tracer.start_as_current_span() to create custom spans
• Add relevant attributes to spans (e.g., location, destination)
• Log information within the span context

Route Instrumentation:

Instrument your Flask routes to capture the full request lifecycle. Add spans for request handling, data validation, and response preparation.

• Wrap the /plan route handler with a span
• Add request-specific attributes (destination, duration, etc.)
• Handle errors and mark spans appropriately

Logging Configuration:

Configure structured logging that automatically includes trace context. This allows you to correlate logs with specific spans in New Relic, making it easier to debug issues.

Example: When a user requests a trip plan, you should see:

• An auto-generated Agent Framework span for the agent orchestration
• Custom spans for each tool call
• Custom spans for business logic (validation, filtering)
• Logs with trace context attached to relevant spans

Validation

When you submit a travel request, you should see a complete trace in New Relic showing:

• Auto-generated Agent Framework spans
• Custom spans for tools and routes
• Logs correlated with spans
• Custom metrics displayed alongside auto-generated metrics

Restart your app again and execute a generate request for a travel plan. Verify that your app appears in New Relic (it can take a few minutes for additional data to appear) as an entity within the Services - OpenTelemetry section. The name of the entity should match the OTEL_SERVICE_NAME you set in the .env file. Dig into Distributed tracing section and look for traces generated by your application. You should see an additional trace group with a name like plan_trip (or similar if you used a different name in for the custom span).

Click into the trace group to see all the individual traces for that group.

Investigate and observe the details of a single trace.

You should see your custom spans (e.g., plan_trip, get_random_destination, etc.) alongside the auto-generated Agent Framework spans. Click into your custom spans to see the attributes you added (e.g., destination names, flight prices, etc.). You should also see any logs that were correlated with those spans.

Success Criteria

To complete this challenge successfully, you should be able to:

• Demonstrate adding custom spans around tool implementations
• Demonstrate adding custom spans around Flask routes
• Verify that structured logging includes trace context
• Validate that custom spans appear in New Relic traces
• Verify that custom metrics appear in New Relic
• Show logs correlated to spans in New Relic using trace context

Learning Resources

• Microsoft Agent Framework Observability
• OpenTelemetry Python Manual Instrumentation
• OpenTelemetry Spans
• OpenTelemetry Metrics
• New Relic Distributed Tracing
• New Relic Log Management

Tips

• Use get_tracer() and get_meter() from Agent Framework for consistency
• Add spans at logical boundaries (function entry/exit)
• Use span attributes to capture relevant context (destination names, flight prices, etc.)
• Structure logs as JSON for easier parsing in New Relic
• Test custom spans in the console before switching to New Relic OTLP
• Use span status to indicate success/failure of operations
• Correlate logs with spans using trace IDs automatically provided by OpenTelemetry