Optimize models for large datasets

**Problem**
When working with config, 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 file, test, or entry point is named. Start by locating the config handling and existing error paths in the terminal agent, then determine which configuration failures need more descriptive messages. Done means the affected errors provide useful debugging context and the relevant behavior is covered by tests.

Written by the indexing model from the issue text.