Devui Tracing

What it demonstrates

DevUI can capture and display the OpenTelemetry (OTel) traces Agent Framework already emits during execution. DevUI does NOT create its own spans — it collects the GenAI spans the framework produces (LLM calls, tool calls, agent runs) and renders them as a timeline in its debug panel. This lesson launches DevUI programmatically with tracing turned on, so a browser session against the agent shows the full span hierarchy: run the agent in the UI, then open the debug panel.

One real excerpt

from agent_framework.devui import serve

agent = await build_agent()  # a Foundry agent with a get_weather tool (a nice span to inspect)

print("Starting DevUI with tracing enabled at http://localhost:8080")
serve(
    entities=[agent],
    tracing_enabled=True,  # wires OTel span capture into the debug panel
)

The gotcha

The programmatic flag is tracing_enabled, not tracing — the CLI equivalent is devui ./agents --tracing. Without an OTLP collector, traces are captured locally and shown only in the DevUI debug panel; to export elsewhere (Jaeger, Zipkin, Azure Monitor, Datadog) set the OTLP_ENDPOINT env var, e.g. OTLP_ENDPOINT=http://localhost:4317. serve() starts a blocking web server and is a normal synchronous call, so build the agent asynchronously in main() first, then hand the finished agent to serve().

Azure / MAF mapping

The traced agent is a plain Agent over FoundryChatClient (project_endpoint + model + AzureCliCredential) with a local get_weather tool. The spans DevUI shows are the GenAI spans the Foundry client and tool execution already emit — tracing is observability layered on top, not a change to how the agent runs.

Run it

uv run tutorial/04-hosting/07_devui_tracing.py — needs Foundry creds (az login) and the hosting extra. Worked if it prints “Starting DevUI with tracing enabled…” then the server blocks; open the URL, run the agent, and inspect the trace timeline.

Next: Getting Started