Improve parsers 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 parser entry points are named. Start by locating the parser and API error-handling paths, then review how current failures are reported; the work is done when those errors are more descriptive and the relevant existing checks still pass.

Written by the indexing model from the issue text.