Desired solution:

I would like to auto invoke my script just after performing Vegas action (i.e. splitting events by S).

@nonam3 One of the best ways to do this is to rewrite a splitting method in your script and then assign S key to your script in Options -> Custom Keyboard.

- is there a build in mechanism to achieve this? I couldn't find anything.
- is scripting API capable of achieving such functionality? (namely firing up method after/before Vegas native tools are used)

If you are writing custom commands, you can use certain events that are triggered after Vegas operations, such as Vegas.TrackEventCountChanged, Vegas.TrackEventStateChanged, Vegas.TrackEventTimeChanged, and so on. However, after these events are triggered, you have to determine whether the action is in line with your expectations before you can perform what you want. It's complicated and not recommended if not necessary.

By the way, for a good running speed, if you are still using .cs scripts, I recommend that you compile them as .dll files to reduce the latency associated with running scripts. The delays in .cs script files are intolerable for such repetitive operations.