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Phase 11

Observability

~2 min read

Concept & How It Works

    Why Does It Exist?

    Agents are non-deterministic distributed systems. Without observability you're blind to which step failed, why latency spiked, or which prompt version caused regressions.

    Real-World Analogy

    Agent observability is an airplane cockpit — instruments for altitude (latency), fuel (tokens/cost), and warning lights (errors) so you don't fly blind.
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    Visual Workflows

    What is Observability?

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    Example

    Scenario

    Dashboard shows Billing Agent p95 latency doubled after a deploy — trace drill-down reveals new retriever returning 20 chunks instead of 5.

    Solution

    In Agent Evaluation & Observability, apply Observability to this scenario: Dashboard shows Billing Agent p95 latency doubled after a deploy — trace drill-down reveals new retriever returning 20 chunks instead of 5. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.

    Practice Task

    Do this before moving to the next module — reading alone is not enough.

    Open the Code Walkthrough below and run it locally. Change one parameter related to Observability (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.

    Code Walkthrough

    Highlighted lines show where Observability happens in the code.

    Observability
    1from opentelemetry import trace  # import dependencies2tracer = trace.get_tracer("support-agent")3
    4with tracer.start_as_current_span("tool.lookup_invoice") as span:5    span.set_attribute("invoice_id", inv_id)6    result = lookup_invoice(inv_id)

    Commands to Remember

    Commands to Remember

    • pip install langsmith # trace and evaluate LLM runs
    • pip install arize-phoenix # open-source LLM observability
    • pip install opentelemetry-api opentelemetry-sdk # distributed tracing

    Common Mistakes

    • Treating Observability as a black box without evaluation
    • Ignoring cost and latency in production
    • Skipping error handling for observability

    Cheat Sheet

    Quick recap — the most important points from this module.

    Cheat Sheet

    quick ref
    • Observability
    • Traces
    • Spans
    • SLIs