# Progress log for Milestone 6 (patch_explainer.py coverage)

Last visited: 2026-06-26T22:28:48Z

- [x] Analyze bug in `patch_explainer.py` (type mismatch on `diff_result.data`)
- [x] Apply JSON deserialization fix in `patch_explainer.py`
- [x] Expand unit tests in `tests/unit/tools/common/test_patch_explainer.py`
- [x] Verify unit tests pass and target file achieves 100% coverage
- [x] Run formatting and linting (black and ruff) on modified files
- [x] Run full project test suite to verify no regressions
- [x] Create handoff report (`handoff.md`)
- [x] Submit handoff to main agent
