agent-framework/dotnet/samples/04-hosting/FoundryHostedAgents/responses/Hosted-Observability

Hosted-Observability

A hosted Agent Framework agent that demonstrates how the Foundry hosting pipeline emits OpenTelemetry traces, metrics and logs with no extra wiring.

The agent has two small tools, GetCurrentLocation and GetWeather, so an end-to-end run produces a span tree covering agent invocation, the underlying chat call, and tool execution.

How it works

Instrumentation is on by default

Unlike the Python SDK, the .NET hosting library is instrumented by default. AddFoundryResponses(agent) automatically wraps the agent with OpenTelemetryAgent (see Microsoft.Agents.AI.Foundry.Hosting.ServiceCollectionExtensions.ApplyOpenTelemetry) and the OTLP exporter pipeline is registered by Azure.AI.AgentServer.Core's AddAgentHostTelemetry(). There is no ENABLE_INSTRUMENTATION flag to set.

Sensitive content

Prompt, completion and tool argument content are omitted from spans by default. Set the OpenTelemetry standard environment variable to capture them:

OTEL_INSTRUMENTATION_GENAI_CAPTURE_MESSAGE_CONTENT=true

This is the .NET equivalent of the Python sample's ENABLE_SENSITIVE_DATA. It is read by OpenTelemetryAgent.EnableSensitiveData.

Where the telemetry goes

Foundry injects APPLICATIONINSIGHTS_CONNECTION_STRING when the agent runs in the hosted environment, so traces, metrics and logs flow to Application Insights with no code change. To send telemetry from a local run, set the connection string yourself in .env.

Prerequisites

• .NET 10 SDK
• An Azure AI Foundry project with a deployed model (e.g., gpt-4o)
• Azure CLI logged in (az login)

Configuration

cp .env.example .env

Edit .env and set your Azure AI Foundry project endpoint:

AZURE_AI_PROJECT_ENDPOINT=https://<your-account>.services.ai.azure.com/api/projects/<your-project>
ASPNETCORE_URLS=http://+:8088
ASPNETCORE_ENVIRONMENT=Development
AZURE_AI_MODEL_DEPLOYMENT_NAME=gpt-4o
OTEL_INSTRUMENTATION_GENAI_CAPTURE_MESSAGE_CONTENT=true

Note: .env is gitignored. The .env.example template is checked in as a reference.

Running directly (contributors)

cd dotnet/samples/04-hosting/FoundryHostedAgents/responses/Hosted-Observability
AGENT_NAME=hosted-observability dotnet run

The agent starts on http://localhost:8088.

Test it

azd ai agent invoke --local "What is the current weather where I am?"

Or with curl:

curl -X POST http://localhost:8088/responses \
  -H "Content-Type: application/json" \
  -d '{"input": "What is the current weather where I am?", "model": "hosted-observability"}'

Expected span tree

A single request produces approximately the following spans:

Span	Source
invoke_agent	Outer span emitted by the Azure AI AgentServer hosting SDK
agent_invoke <name>	Emitted by OpenTelemetryAgent for each agent invocation
chat <model>	Emitted by the underlying IChatClient for each model call
execute_tool <tool>	Emitted for each invocation of GetCurrentLocation / GetWeather

See the OpenTelemetry GenAI semantic conventions for the attributes captured on each span.

Running with Docker

This project uses ProjectReference to the local Agent Framework source, so use Dockerfile.contributor with a pre-published output:

dotnet publish -c Debug -f net10.0 -r linux-musl-x64 --self-contained false -o out
docker build -f Dockerfile.contributor -t hosted-observability .

export AZURE_BEARER_TOKEN=$(az account get-access-token --resource https://ai.azure.com --query accessToken -o tsv)
docker run --rm -p 8088:8088 \
  -e AGENT_NAME=hosted-observability \
  -e AZURE_BEARER_TOKEN=$AZURE_BEARER_TOKEN \
  --env-file .env \
  hosted-observability

Deploying to Foundry and viewing traces

Once deployed, telemetry flows to the Application Insights instance attached to your Foundry project. In the Foundry UI, the Traces tab next to Playground lists conversations and lets you drill into the span tree for any request.

NuGet package users

If consuming the Agent Framework as a NuGet package, use the standard Dockerfile instead of Dockerfile.contributor. See the commented section in HostedObservability.csproj for the PackageReference alternative.