Couldn’t you do this with a type annotation? e.g. SQLAlchemy could have a SQL type so tools like mypy could see a Template instance and confirm you’re using it safely but Black, Ruff, or SQLFluff could look for the more specialized Annotated[Template, SQL] to realize that the template could be formatted as SQL, and something like Django could even have Annotated[Template, Email], Annotated[Template, HTML], or Annotated[Template, JSX] to indicate what context the same templating syntax is targeting.