> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appsignal.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom Instrumentation

AppSignal is compatible with OpenTelemetry instrumentation packages.

This does not always include the information you need to debug issues.
For more fine-grained reporting, you can add custom instrumentation.

We support [OpenTelemetry tracing](https://opentelemetry.io/docs/) as laid out in the OpenTelemetry documentation.
It's possible to add more data to span using OpenTelemetry span attributes.

There are also AppSignal span attributes that can change how traces are grouped and some attributes that allow for filtering out sensitive data.

The AppSignal span attributes are described in more detail in our [OpenTelemetry Custom Instrumentation Attributes](/opentelemetry/custom-instrumentation/attributes) section.