A notification template is a function signature we pretend is a string. The arguments go untyped, so a missing order_id fails at the provider, not in CI.
Declare the variables, validate before dispatch, and the failure moves back to your test suite where it costs nothing. That part is cheap. Who owns that contract, backend or whoever wrote the copy, is probably less settled on your team than it looks. https://shipmindlabs.com/c/cc5346c3