diff --git a/docs/CODEX_EXECUTION_LOG.md b/docs/CODEX_EXECUTION_LOG.md
index c3736e48..47d2e651 100644
--- a/docs/CODEX_EXECUTION_LOG.md
+++ b/docs/CODEX_EXECUTION_LOG.md
@@ -11905,3 +11905,38 @@ Open:
   and pure-background results only if every regional calibration gate passes.
 - Continue failure-driven, train-only corpus iterations until all objective
   gates pass; only then request the queued representative human review.
+
+## 2026-07-29 - V42 regional corpus expansion and v43 loop handoff
+
+Changed:
+
+- Added and acquired 14 independent train-only AOIs spanning Flemish coastal,
+  port, dunes, industrial and ribbon contexts plus Walloon architecture,
+  rural, industrial, quarry, forest and field contexts.
+- Built immutable 156-sample v42 evidence, applied the governed temporal
+  filters, refined the new labels with SAM2 on CUDA and retiled all new source
+  labels with 384 px tiles and 128 px overlap without uncovered labels.
+- Rotated the training corpus while retaining the exact protected v31
+  calibration, test and background assignments.
+- Added the versioned v43 command for calibration-first evaluation followed by
+  at most 20 failure-driven CUDA iterations. It starts from the rejected v38
+  iteration-5 checkpoint and shortens patience to 8 because all preceding runs
+  selected epoch 2 while later epochs overfit the protected regional pattern.
+
+Verified:
+
+- Corpus audit: 156 samples, no automated failures and no reported leakage.
+- Training tile audit: `ok`; 2,160 tiles, 56,474 valid labels, zero invalid or
+  missing labels, 270 negative tiles and zero repeated background negatives.
+- New-AOI visual renderer: `ok`; 56 rendered tiles spanning all 14 added AOIs,
+  with zero missing inputs, invalid rows or low-variance imagery. Manual
+  AI-assisted inspection found labels aligned with visible roof footprints and
+  retained the deliberately sparse hard-negative contexts.
+- NVIDIA preflight: RTX 4080 SUPER idle and available before the v43 handoff.
+
+Open:
+
+- Complete v43 calibration convergence, then and only then evaluate the closed
+  protected test and pure-background sets.
+- Obtain final representative human contact-sheet approval, promote the exact
+  checksummed model, and redeploy from the canonical Tower directory.
diff --git a/docs/TODO.md b/docs/TODO.md
index 00fb73d3..b01dcbd4 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -1010,3 +1010,14 @@ This file now starts with the current implementation status. Older preparation/b
 - [x] Produce a dark campaign cover, architecture visual, AI pipeline visual and animated project GIF.
 - [x] Generate and visually verify a six-page portfolio case-study PDF.
 - [x] Commit, push and redeploy the complete presentation release from `/mnt/user/appdata/geointel`.
+
+# Sprint 232 - V42 Belgian building generalisation loop
+
+- [x] Add 14 independent coastal, industrial, rural, quarry, forest, field and port training AOIs across Flanders and Wallonia.
+- [x] Acquire, temporally filter, SAM2-refine and overlap-retile the new AOIs on the RTX 4080 SUPER.
+- [x] Assemble and checksum the immutable 156-sample v42 corpus while preserving the protected v31 calibration/test/background assignments.
+- [x] Pass structural corpus and 56,474-label tile-quality audits with zero invalid or missing labels and zero spatial leakage failures.
+- [x] Render and inspect a 56-tile contact sheet covering all 14 new AOIs before retraining.
+- [ ] Run the v43 calibration-first, failure-driven CUDA loop against the frozen regional release gates.
+- [ ] Open protected test and pure-background evidence only after every calibration gate passes.
+- [ ] Queue final representative human sign-off only after all automated gates pass, then promote and redeploy the exact checksummed model.
diff --git a/scripts/tower-v43-v42-loop-command.json b/scripts/tower-v43-v42-loop-command.json
new file mode 100644
index 00000000..d6ce0e1e
--- /dev/null
+++ b/scripts/tower-v43-v42-loop-command.json
@@ -0,0 +1,73 @@
+[
+  "docker",
+  "exec",
+  "-d",
+  "geointel",
+  "/opt/geointel/venv/bin/python",
+  "/app/scripts/run_belgium_building_training_loop.py",
+  "--initial-model",
+  "/app/storage/training/building-be-v38-v31-closed-loop-r1/iteration-005/candidate.pt",
+  "--train-yaml",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/train/dataset.yaml",
+  "--train-summary",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/train/yolo_tile_dataset_summary.json",
+  "--dataset-audit",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/audit/belgium-building-corpus-audit.json",
+  "--train-quality-audit",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/train/audit/operator_yolo_dataset_quality_audit.json",
+  "--calibration-summary",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/calibration/yolo_tile_dataset_summary.json",
+  "--test-summary",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/test/yolo_tile_dataset_summary.json",
+  "--background-summary",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/background-test/yolo_tile_dataset_summary.json",
+  "--corpus-manifest",
+  "/app/storage/operator-data/building-be-v42-rotated-holdouts-r1/operator_samples_manifest.json",
+  "--output-dir",
+  "/app/storage/training/building-be-v43-v42-closed-loop-r1",
+  "--iterations",
+  "20",
+  "--epochs",
+  "80",
+  "--patience",
+  "8",
+  "--batch",
+  "8",
+  "--workers",
+  "0",
+  "--max-det",
+  "1000",
+  "--imgsz",
+  "640",
+  "--optimizer",
+  "AdamW",
+  "--lr0",
+  "0.0001",
+  "--mosaic",
+  "0",
+  "--scale",
+  "0.15",
+  "--translate",
+  "0.05",
+  "--degrees",
+  "180",
+  "--flipud",
+  "0.5",
+  "--fliplr",
+  "0.5",
+  "--warmup-epochs",
+  "1",
+  "--warmup-bias-lr",
+  "0.01",
+  "--hsv-h",
+  "0.01",
+  "--hsv-s",
+  "0.2",
+  "--hsv-v",
+  "0.15",
+  "--seed",
+  "20260942",
+  "--yolo",
+  "/opt/geointel/venv/bin/yolo",
+  "--evaluate-initial-model"
+]