During their work on the deepset-ai/haystack repository, Pelyh addressed a reliability issue in the retrieval pipeline by ensuring that the mime_type attribute is correctly populated for streams fetched from a single URL in the LinkContentFetcher component. Using Python and YAML, they derived the mime_type from existing content_type metadata, which prevented downstream failures in modules such as FileTypeRouter. Pelyh updated the test suite to validate the new propagation path, reinforcing data quality and metadata handling. Their contribution demonstrated careful bug fixing, disciplined git workflows, and a focus on maintainability, though the scope was limited to a targeted, isolated improvement.