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We explore the quantum superposition of boundary conditions in the context of the Poincaré patch of the two-dimensional anti–de Sitter space. Focusing on Robin (mixed) boundary conditions, we investigate the response function of the Unruh-DeWitt (UDW) detector interacting with two or more scalar fields, each respecting a different boundary condition. The role of this quantum superposition is twofold: (i) it may represent different fields propagating on the same spacetime and interacting with an UDW detector or (ii) it may describe an UDW detector on a superposition of spacetimes, each one with an inequivalent propagating field.