diff --git a/py_workspace/.sisyphus/notepads/ground-plane-refinement/learnings.md b/py_workspace/.sisyphus/notepads/ground-plane-refinement/learnings.md
index edc4fb0..390d9ac 100644
--- a/py_workspace/.sisyphus/notepads/ground-plane-refinement/learnings.md
+++ b/py_workspace/.sisyphus/notepads/ground-plane-refinement/learnings.md
@@ -30,3 +30,10 @@
 - Full test suite (90 tests) passed successfully.
 - basedpyright verified on new modules (depth_save.py, ground_plane.py, refine_ground_plane.py).
 - README updated with Ground Plane Refinement workflow.
+
+## [2026-02-09] Documentation Hardening
+- Updated `docs/calibrate-extrinsics-workflow.md` with detailed implementation notes.
+- Documented the HDF5 depth data schema for reproducibility.
+- Clarified the "Consensus-Relative Correction" strategy vs. absolute alignment.
+- Added explicit tuning guidance for `stride`, `ransac-dist-thresh`, and `max-rotation-deg` based on implementation constraints.
+