# Code Comment Policy

UnifiedSpread source comments should explain intent, contracts and extension seams rather than restating obvious syntax.

## Required comment targets

- Main classes and singleton services.
- Public methods called by Host-facing Control, commands or adapters.
- Complex helpers in Formula, Selection, Range, Merge, Filter, Sort, File I/O and XLSX/CSV conversion.
- TODO / future extension points where behavior is intentionally partial.

## dev-20.5.1 applied areas

- `native_grid_model.js`
- `native_grid_renderer.js`
- `native_grid_engine.js`
- `workbook_service.js`
- `engine-adapter.js`
- `menu.js`