Improve routes performance

**Problem**
When working with routes, 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 route entry points are named in the issue. Start by locating the route handling and error paths in the Shell-based terminal agent, then clarify whether the goal is performance, more descriptive errors, or both; done should be verified with focused route checks showing the agreed behavior.

Written by the indexing model from the issue text.