Kostas Papageorgiou enhanced log schema validation in the panther-labs/panther_analysis_tool repository by expanding support for YAML test files, addressing both _tests.yaml and _tests.yml suffixes. Using Python and YAML, Kostas implemented logic to ensure consistent discovery and validation of schema test files, introducing new test fixtures to verify this behavior. The work focused on backend development and schema validation, improving the tool’s ability to catch configuration errors and increasing the reliability of data quality checks. By strengthening test coverage and feedback loops, Kostas enabled faster detection of issues and contributed to more robust analysis workflows within the project.