During December 2025, contributed to the pydantic-ai repository by enhancing the ToolRetryError exception to deliver clearer and more actionable error messages. Focused on improving error formatting and exception handling in Python, the work involved reformatting validation errors surfaced from RetryPromptPart to improve readability and developer understanding. Developed targeted unit tests to verify the reliability and consistency of the new error message formatting across various failure scenarios. These changes aimed to streamline the debugging process and support faster issue resolution, resulting in a more maintainable codebase and improved developer experience for those working with error handling in pydantic-ai.