A tracing system may use an evaluation mechanism to determine which functions to include or exclude during tracing. The architecture may evaluate functions when functions or groups of functions may be loaded for execution, as well as each time a function may be encountered. The evaluation mechanism may use whitelists, blacklists, and various expressions to identify which functions to trace and which functions to exclude. The evaluation mechanism may evaluate an expression that may identify specific conditions under which a function may be traced or not traced. The tracing mechanism may create wrapping functions for each function, including callback functions.