Consider deprecating old core API

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

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

**Priority**: Low/Medium

Start by locating the handler entry points and current core API usage. Clarify whether the intended work is deprecating the old API, adding configurable filtering, or both; document the filtering defaults and affected behavior before defining completion criteria and tests.

Written by the indexing model from the issue text.