Add rate limiting for serialization

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

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

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

The issue does not name any files, tests, or entry points. First clarify whether the goal is rate limiting serialization or improving authentication error messages, then identify the relevant serialization and authentication paths and define tests and acceptance criteria for the intended behavior.

Written by the indexing model from the issue text.