A useful role lets you contribute without requiring you to become the solution to every nearby problem.

Capable people attract adjacent work. You do one thing well, and everything that touches it starts arriving on your desk, until the role you agreed to has become a general responsibility for whatever is broken nearby. The drift is gradual enough that no single request looks unreasonable.

Write down what your part actually is, in a sentence you could say aloud. When something outside it comes to you, help once if you can, and say clearly where the boundary sits rather than letting it move again.