A system for providing a graphics tool access to a computer graphics system to evaluate and control a graphics application executing on the computer graphics system. The system includes application program interface (API) event generators for performing predetermined operations relating to a graphics library function call and for generating a hook event containing results of the predetermined operations; dispatch table manger for selecting an active dispatch table from a normal operations dispatch table having function pointer to the graphics library finctions and a hooks dispatch table having pointer to the API event generators; and hook event manager for enabling and configuring selected ones of the API event generators in response to a graphics tool event request. The system further includes internal event generators, integrated along various locations of a graphics pipeline managed by the graphics library, for performing predetermined diagnostic operations in the graphics system. In this embodiment the hook event manager also enables and configures selected ones of the internal event generators.