Improve error messages in controllers

**Description**
Currently middleware lacks proper search support.

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

**Priority**: Low/Medium

Start by locating the middleware and controller entry points in the repository, then trace how requests are currently searched. Clarify the intended search behavior and configuration surface before making changes. Done means configurable search is available with sensible defaults and the controller error behavior matches the issue title.

Written by the indexing model from the issue text.