Improve middleware performance

**Problem**
When working with api, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No files, tests, or entry points are named. Start by locating the middleware and its existing API error-handling paths, then clarify whether the goal is performance, more descriptive errors, or both. Done should be defined by agreed error details and any performance criteria, with tests covering the resulting behavior.

Written by the indexing model from the issue text.