update todos

docs/AGENTS.md

@@ -194,3 +194,40 @@ for i in range(10):
   ```
 ```
 </markdown_spec>
+
+<test_coverage>
+## Test Coverage Tracking
+
+The project uses SimpleCov to track test coverage. Coverage data is stored in `coverage/.resultset.json` after each test run.
+
+### Coverage Information
+- **Location**: `coverage/.resultset.json`
+- **Format**: JSON file with line-by-line coverage data for each Ruby file
+- **Generated by**: SimpleCov gem (runs automatically with tests)
+- **HTML Report**: `coverage/index.html` (open in browser for detailed report)
+
+### Reading Coverage Data
+
+When checking test coverage:
+1. Run tests: `bin/rails test`
+2. Check overall coverage in console output (e.g., "Line Coverage: 85.7% (707 / 825)")
+3. For detailed per-file coverage: open `coverage/index.html` in a browser
+4. The `.resultset.json` file contains raw coverage data if programmatic access is needed
+
+### Coverage Goals
+- Aim for **80%+ line coverage** for all models and helpers
+- Controllers should have **all actions tested** (both success and error paths)
+- Critical business logic should have **100% coverage**
+
+### Files Excluded from Coverage
+- `config/` - Configuration files
+- `db/` - Database migrations and schema
+- `test/` - Test files themselves
+- `vendor/` - Third-party code
+
+### Coverage Notes for Agents
+- Always run tests after making changes to verify coverage isn't decreasing
+- If adding new methods/classes, add corresponding tests
+- Coverage report shows which lines are NOT covered (highlighted in red in HTML report)
+- Missing coverage often indicates edge cases or error paths not tested
+</test_coverage>