An instrumentation client API is provided within a managed code runtime environment for accessing instrumentation data that resides outside of the managed code runtime environment. The instrumentation client API provides access to instrumentation data in a manner that is consistent with the classes and models provided by the runtime environment, raises exceptions in a manner that is compatible with the runtime environment, and is secure. The instrumentation client API wraps, or translates, calls to and from an instrumentation data source external to the runtime environment. The API interacts with an interface provided by the instrumentation data source to provide functionality and connectivity that is not otherwise provided by the instrumentation data source. The API also provides access to instrumentation data in a manner that is consistent with the models and classes provided by the runtime platform. The classes defined by the API return collections and exceptions in a way that is consistent with the managed code runtime platform.