diff --git a/docs/development/build_execution_tracker.md b/docs/development/build_execution_tracker.md
index fc32ac7..8f26a74 100644
--- a/docs/development/build_execution_tracker.md
+++ b/docs/development/build_execution_tracker.md
@@ -3,8 +3,8 @@
 ## Current status
 
 - main baseline updated through: feat/wc-catalog-expansion-ui (Stage 9D complete)
-- next branch: feat/square-catalog-sync (Stage 10B — Square catalog and inventory sync)
-- current stage: Stage 10A complete — `SquareApiClient` implementing `ApiClient` contract; Catalog, Inventory, Orders, and Payments API methods; `SquareApiException` extending `ApiException`; `KcAppEnvironment.square` and `.multi` values; `KC_SQUARE_ACCESS_TOKEN`, `KC_SQUARE_LOCATION_ID`, `KC_SQUARE_ENVIRONMENT` dart-define keys; 88 tests passing; analyze clean
+- next branch: feat/square-catalog-sync (Stage 10B — Square catalog and inventory sync) — **in progress on branch**
+- current stage: Stage 10B in progress — `SquareProductMapper`, `SquareInventoryMapper`, `ProductIdMapping` domain model, `ProductIdMappingRepository` contract, `FakeProductIdMappingRepository`; integrations 123/123 tests passing; feature_wordpress product_id_mapping 23/23 tests passing; analyze clean; commit `a6f888c` on `feat/square-catalog-sync`
 
 ## Slice tracker
 
@@ -572,3 +572,23 @@
 - tests: passed (88/88 integrations, 24/24 kell_web, 26/26 kell_mobile, 424/424 feature_wordpress, 132/132 feature_inventory, 198/198 feature_orders, 41/41 design_system, 24/24 core — 957 total)
 - analyze: passed (dart analyze --fatal-infos — no issues found across all 11 packages/apps)
 - brief updated: yes
+
+### feat/square-catalog-sync
+
+- status: in progress on branch (commit `a6f888c`)
+- date: 2026-07-25
+- inspection: complete
+- implementation: complete (Stage 10B slice)
+- files changed:
+  - `integrations/lib/src/square_product_mapper.dart` — new `SquareProductMapper`; `fromSquareCatalogObject()` maps Square ITEM CatalogObject JSON → `ChannelProduct` (cents→dollars, `is_deleted` → `archived` status, first-variation SKU/price extraction); `fromSquareCatalogList()` batch variant skipping non-ITEM entries; `toSquareCatalogObject()` maps `ChannelProduct` → Square ITEM JSON (dollars→cents rounding, default variation with `FIXED_PRICING`, `location_overrides` with `track_inventory`, optional description/SKU omitted when null)
+  - `integrations/lib/src/square_inventory_mapper.dart` — new `SquareInventoryMapper`; `fromSquareInventoryCount()` maps Square InventoryCount JSON → `ChannelInventoryCount` (IN_STOCK only, string quantity parsed safely); `fromSquareInventoryCountList()` batch variant; `toSquareBatchChangeEntry()` maps `ChannelInventoryCount` → Square PHYSICAL_COUNT batch-change entry (quantity as string, RFC 3339 timestamp); `toSquareBatchChangeEntries()` batch variant
+  - `integrations/lib/integrations.dart` — added `square_inventory_mapper.dart` and `square_product_mapper.dart` to barrel exports
+  - `integrations/test/square_catalog_sync_test.dart` — 35 new tests: `SquareProductMapper` (20: fromSquareCatalogObject ×9, fromSquareCatalogList ×3, toSquareCatalogObject ×6) and `SquareInventoryMapper` (15: fromSquareInventoryCount ×8, fromSquareInventoryCountList ×3, toSquareBatchChangeEntry ×3, toSquareBatchChangeEntries ×2)
+  - `feature_wordpress/lib/src/domain/product_id_mapping.dart` — new `ProductIdMapping` value object with `localId`, `wooCommerceId`, `squareCatalogObjectId`, `squareVariationId`, `lastUpdated`; `copyWith()`, `==`/`hashCode`, `toString()`
+  - `feature_wordpress/lib/src/domain/product_id_mapping_repository.dart` — new `ProductIdMappingRepository` abstract contract: `getAllMappings()`, `getMappingByLocalId()`, `getMappingByWooCommerceId()`, `getMappingBySquareId()`, `saveMapping()` (upsert), `deleteMapping()` (no-op safe)
+  - `feature_wordpress/lib/src/data/fake_product_id_mapping_repository.dart` — new `FakeProductIdMappingRepository` in-memory implementation; seeded with 6 mappings matching fake catalog (products 1–3 fully synced with Square IDs, products 4–5 WooCommerce-only, product 6 draft/unsynced); 50ms simulated async delay on all operations; `getAllMappings()` returns `List.unmodifiable`
+  - `feature_wordpress/lib/feature_wordpress.dart` — added `fake_product_id_mapping_repository.dart`, `product_id_mapping.dart`, `product_id_mapping_repository.dart` to barrel exports
+  - `feature_wordpress/test/product_id_mapping_test.dart` — 23 new tests: `ProductIdMapping` (7: fields, null defaults, copyWith, equality, hashCode, toString) and `FakeProductIdMappingRepository` (16: getAllMappings, getMappingByLocalId, getMappingByWooCommerceId, getMappingBySquareId, seed state, saveMapping insert/replace/count, deleteMapping remove/count/no-op, unmodifiable list)
+- tests: passed (123/123 integrations ← +35 new; 23/23 feature_wordpress product_id_mapping ← +23 new)
+- analyze: clean (no new issues introduced)
+- brief updated: pending