diff --git a/phases/cpp-object-oriented-modular-refactoring/index.json b/phases/cpp-object-oriented-modular-refactoring/index.json
index 4c8717a..ed9ddc9 100644
--- a/phases/cpp-object-oriented-modular-refactoring/index.json
+++ b/phases/cpp-object-oriented-modular-refactoring/index.json
@@ -37,7 +37,10 @@
     {
       "step": 4,
       "name": "model-element-google-style",
-      "status": "pending"
+      "status": "completed",
+      "summary": "RED: MSVC direct /c of tests/unit/model/domain_test.cpp against the Step 3 HEAD include tree exited 2 with expected C1083 missing fesa/model/domain.h; GREEN/VERIFY: fesa_unit_tests build, focused CTest 37/37, clang-format 14 files, full MSVC Debug build, CTest discovery 144, and full CTest 144/144 passed; migrated the five model/element headers, APIs, members, enums, helpers, and repository callsites to .h guards and Google naming with production-only Doxygen while preserving B33/MITC4 numerical and reference contracts.",
+      "started_at": "2026-08-16T04:26:15+0900",
+      "completed_at": "2026-08-16T05:37:40+0900"
     },
     {
       "step": 5,