Set up .NET Aspire dashboard and configure OpenTelemetry for local development monitoring. Use when: adding Aspire orchestration, OpenTelemetry instrumentation, OTLP exporter, distributed tracing, metrics, structured logging, Aspire dashboard, service defaults, or local observability.
User request
├─ "Add Aspire to my solution"
│ → Phase 1: Scaffold AppHost + ServiceDefaults
│ → Phase 2: Configure dashboard (auto with AppHost)
│ → Phase 3: Wire up OpenTelemetry via ServiceDefaults
│
├─ "Run Aspire Dashboard standalone"
│ → Phase 2: Docker standalone dashboard
│ → Phase 3: Manual OpenTelemetry setup (no Aspire SDK)
│
├─ "Add OpenTelemetry only"
│ → Phase 3: Manual OTel instrumentation
│
└─ "Full local observability"
→ Phase 1 + 2 + 3 + health checks
builder.AddServiceDefaults() and app.MapDefaultEndpoints()https://localhost:18888/health, /alive)dotnet build succeeds for the entire solution