In recent years, the world of VLSI testing has been living a huge transformation pushed by constraints and requirements coming from a large variety of sources and applications. The traditional need for higher accessibility and controllability led to solutions such as IEEE 1687, while the need for reuse is pushing for innovations like P1687.1. All the while, these same features are raising security concerns for malicious attacks or reverse engineering. Standards usual approach of relying on Domain-Specific Languages to convey information to the EDA tools has difficulty in handling such disparate and often conflicting needs, with the risk of a dangerous proliferation of custom and incompatible solutions. In this paper, we show how the usage of Callbacks, defined in P1687.1, can help solve this issue.