A probe management system identifies a probe module for an application, which includes a semaphore table that has entries for a plurality of probe points in the application. An entry includes a semaphore variable value for a probe point. The probe management system identifies one or more probe points that are to be activated from an introspection user script. The user script is for examining the execution of the application at one or more of the probe points in the application. The probe management system adjusts the semaphore variable values for the identified probe points in the semaphore table in the probe module to represent to the application that a probe point is to be activated and causes the application to activate the identified probe points based on the adjusted semaphore variable values in the semaphore table.