Extension points

Everything in the pipeline is registered through DI. You can replace defaults or add to the enumerable extension points.

Interface	Purpose	Registered via
SQL DDL files (desired)	The desired schema and any inline PRE/POST DEPLOYMENT scripts.	AddDdlSchemas(...) (may be called more than once; sources aggregate)
ISchemaProvider (online current)	Read the current live database schema.	UseCurrentSchema<T>() (or via a provider package, e.g. UseCurrentSchemaPostgres(...))
ISchemaPolicy	Validate the merged desired schema.	AddSchemaPolicy<T>()
IDiffPolicy	Validate the structured diff (e.g. the built-in destructive-action policy).	AddDiffPolicy<T>()
ISqlGenerator	Generate the SQL for a migration plan, keyed by Dialect. Add support for another database.	AddSqlGenerator<T>(dialect) (or via a provider package); select with WithDialect(...)
ISchemaStateStore	Optional backend state store for tracking the last applied schema.	UseStateStore<T>() / UseStateStore(instance) / UseFileStateStore(path)

Less commonly used extension points

These extension points are less commonly used, but still available for advanced scenarios.

Interface	Purpose	Registered via
IDiffRenderer	Customize how the migration diff is rendered to text (e.g. JSON instead of Terraform-style).	UseTerraformRenderer(...) / UseDiffRenderer<TRenderer>()
ISqlPlanRenderer	Customize how the SQL preview is rendered to text (e.g. JSON for CI).	UseSqlPlanRenderer<TRenderer>()
IOperationReporter	Customize run output. Register several and select one via NSchemaApplicationOptions.Reporter.	AddReporter<T>(format) / AddReporter(instance) (last-wins per key)