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commands/create-integration.md

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+---
+description: Create a new auto-instrumentation integration
+---
+
+Create a new auto-instrumentation integration for the Datadog .NET tracer.
+
+Follow these steps:
+
+1. **Gather requirements**:
+   - Target library name and NuGet package
+   - Supported version range
+   - Methods to instrument (assembly, type, method signatures)
+   - Integration category (e.g., HTTP, Database, Messaging, etc.)
+
+2. **Create integration class**:
+   - Location: `tracer/src/Datadog.Trace/ClrProfiler/AutoInstrumentation/<Area>/<Integration>.cs`
+   - Add `[InstrumentMethod]` attribute with:
+     - `AssemblyName`: Target assembly
+     - `TypeName`: Fully qualified type name
+     - `MethodName`: Method to instrument
+     - `ReturnTypeName`: Method return type
+     - `ParameterTypeNames`: Array of parameter types
+     - `MinimumVersion` and `MaximumVersion`: Version range
+     - `IntegrationName`: Unique integration identifier
+   - Implement `OnMethodBegin` (for method entry)
+   - Implement `OnMethodEnd` or `OnAsyncMethodEnd` (for method exit)
+
+3. **Use duck typing for third-party types**:
+   - Define interface with required properties/methods
+   - Use `where TTarget : IMyInterface, IDuckType` constraint
+   - Or use `target.DuckCast<IMyInterface>()` for runtime casting
+
+4. **Add integration tests**:
+   - Location: `tracer/test/Datadog.Trace.ClrProfiler.IntegrationTests/<Area>/`
+   - Create sample application: `tracer/test/test-applications/integrations/<Library>/`
+   - Test multiple library versions (package_versions.props)
+   - Verify spans are created with correct tags
+
+5. **Generate boilerplate**:
+   - Run: `./tracer/build.ps1 RunInstrumentationGenerator`
+
+6. **Update documentation**:
+   - Add integration to supported libraries list if needed
+
+Reference files:
+- `docs/development/AutomaticInstrumentation.md` - Complete integration guide
+- `docs/development/DuckTyping.md` - Duck typing patterns
+- `tracer/src/Datadog.Trace/ClrProfiler/AutoInstrumentation/` - Existing integrations
+
+After creating:
+- Run the instrumentation generator
+- Build the tracer
+- Run integration tests
+- Verify spans in test output