Month: 2026-07 — Weaviate core repository focus on API validation, reliability, and test coverage. Key features delivered: Batch Delete API Validation Feedback. Major bugs fixed: batch delete previously returned 500 for missing required match fields; now returns 422 Unprocessable Entity. Changes included updating batch manager validation and adding unit tests to verify error classification for invalid user input. Commit reference: e5df0ce6d807e4ec7f5c7b6747ce6723a47ba336 - gh-12041 return 422 for batch delete with missing match fields. Impact: reduces backend errors and misclassification, improves API client experience, and strengthens data integrity and user guidance. Technologies/skills demonstrated: API validation and error handling, REST semantics (HTTP 422 vs 500), batch processing workflows, unit testing and test-driven validation, and commit hygiene in collaborative development.