WORK_LOG.md

@@ -135,3 +135,41 @@ Contract tests were added and updated to cover explicit route group metadata par
 mxpic_router/mxpic_router/eda_loader.py
 mxpic_router/mxpic_router/builder.py
 mxpic_router/tests/test_eda_router_contract.py
+
+
+## 2026-06-10
+
+### Scope
+
+Frontend/backend routing metadata integration and electrical routing behavior review.
+
+### Summary
+
+Recent work focused on aligning the backend route grouping logic with the updated EDA frontend bundle-group export format, and reviewing why resistor routes were not using PCB-style routing.
+
+### Completed Work
+
+#### 1. Frontend Bundle Group Integration
+
+The updated frontend exports user-selected route bundle groups as YAML bundle keys instead of duplicating `bundle_group` inside each link.
+
+The backend route grouping logic was updated to treat custom YAML bundle keys as explicit route groups for S-bend `Lstart` spacing.
+
+Default groups such as `output_bus`, `free_wires`, and `free_wires_*` are still treated as fallback groups to avoid unintentionally merging unrelated free-wire routes.
+
+#### 2. Contract Test Update
+
+A contract test was added to verify that custom frontend bundle keys are recognized as backend route groups, while default bundle names remain excluded from explicit grouping.
+
+#### 3. PCB Routing Condition Review
+
+The PCB routing condition was reviewed for resistor-based test layouts.
+
+The backend currently enables `PCB=True` based on route `xsection` only. Routes using `metal_1`, `metal1`, `metal_2`, or `metal2` enable PCB routing; routes exported as `strip` remain optical-style routes.
+
+The current resistor test YAML was found to export `xsection: strip` and `family: optical`, so the issue was traced to frontend route metadata export rather than the backend PCB flag logic.
+
+### Modified Files
+
+mxpic_router/mxpic_router/builder.py
+mxpic_router/tests/test_eda_router_contract.py