The test for a context boundary is whether the same word means the same thing on both sides, not whether the code is in separate directories.
"order" in fulfilment: a set of lines to pick and pack.
cancelled means do not ship.
"order" in finance: a revenue event with a tax
treatment. cancelled means issue
a credit note.
same word, two models, and forcing one shared Order class
means a class with fields half of it ignores.
the translation between them is the interesting part, and
it belongs in one explicit place.A shared model across two contexts accumulates optional fields until nobody can say what a valid instance looks like, which is the observable symptom of a missing boundary. Two models and an explicit translation is more code and is the version where each model can be understood on its own.