# Validator

The first validator entry point is:

```bash
railiance-fabric validate <repo-or-file>...
```

It accepts:

- a repo root containing `fabric/`
- a `fabric/` directory
- one or more declaration YAML files

The validator currently checks:

- YAML load errors
- declaration schema conformance
- duplicate graph IDs
- unknown capability and interface types
- missing service, capability, interface, dependency, and binding references
- missing provider capabilities for dependencies
- binding provider/dependency capability type mismatches
- active production dependencies without `metadata.source_links`
- active production dependencies whose providers do not cover the environment
- service dependency cycles from binding assertions

Exit behavior:

- exits `0` when there are no errors
- exits `1` when errors are present
- exits `1` for warnings only when `--warnings-as-errors` is used

Examples:

```bash
PYTHONPATH=. python -m railiance_fabric.cli validate .
PYTHONPATH=. python -m railiance_fabric.cli validate fabric/
PYTHONPATH=. python -m railiance_fabric.cli validate examples/declarations/invalid/*.yaml
```