# Rule 4: Component Isolation & Skeletal Troubleshooting

- **Targeted Testing**: If a bug is found, DO NOT rely on testing the full stack. You must isolate and test the offending class or method directly.
- **Skeletal Reproducers**: If the issue spans across boundaries (e.g., between server, stub, or nvim), you must create skeletal (minimal reproducible) versions of those components.
- **Purpose**: Troubleshooting must be done on these skeletal versions to isolate the broken feature or aspect without the noise, side-effects, or overhead of the full application stack.