opentelemetry-net-instrumentation

1# OpenTelemetry .NET Instrumentation Skill
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3## When to Use
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5- Adding OpenTelemetry instrumentation to .NET code (traces, metrics, logs)
6- Creating or modifying ActivitySources, Meters, or ILogger usage
7- Setting up the OpenTelemetry SDK, resources, exporters, or sampling
8- Reviewing telemetry implementations for spec compliance
9- Optimizing instrumentation performance
10- Designing telemetry APIs that become part of the public surface
11- Implementing context propagation across service boundaries
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13## Architecture: .NET Is Different
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15**CRITICAL**: The .NET OpenTelemetry implementation is fundamentally different from other platforms. .NET provides tracing, metrics, and logging APIs **in the framework itself**.
16That means **OTel does not provide a separate instrumentation API** — it uses the built-in .NET APIs and acts as the collection/export layer.
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18### The Three Built-in .NET APIs (Primary — Zero Dependencies)
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20| Signal | .NET Framework API | Namespace |
21|--------|-------------------|-----------|
22| **Tracing** | `ActivitySource` / `Activity` | `System.Diagnostics` |
23| **Metrics** | `Meter` / `Counter<T>` / `Histogram<T>` / etc. | `System.Diagnostics.Metrics` |
24| **Logging** | `ILogger<T>` | `Microsoft.Extensions.Logging` |
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26These are **the primary and only APIs** library authors should use for instrumentation.
27They ship with the .NET runtime — **no NuGet packages required**.
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29### The OTel Collection/Export Layer (Secondary — Application Root Only)
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