Update handlers documentation

**Description**
Currently data lacks proper filtering support.

**Proposed solution**
Add configurable filtering with sensible defaults.

**Priority**: Low/Medium

No file, test, or entry point is named. Start by locating the handlers and tracing how data is currently processed; clarify whether the request is implementation work, documentation work, or both. Done should include configurable filtering with sensible defaults and updated handler documentation.

Written by the indexing model from the issue text.