Validate Config
Domain: Configuration
Motivation
Validation runs before a profile boots and before any config write touches disk. Plugins validate their configuration against the composed schemas at load, so an invalid mode or unknown field fails loud instead of silently changing behavior. The config editor validates the complete candidate write before committing, and invalid values leave the file unchanged.
Concrete Example
An unknown top-level key in .credentials.yaml fails at startup rather than being silently ignored.
Analogy
It is the type-check that must pass before your config is allowed to run.