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

# SpanAttributeCoverage

> Coverage info for a single span attribute key.

## Attributes

<ResponseField name="key">
  Span attribute key, exactly as stored — copy it verbatim into a
  [`FieldMapping`](/sdk-api/evals/field-mapping).
</ResponseField>

<ResponseField name="count">
  Number of scanned spans that carry this attribute key.
</ResponseField>