When you click on a Tool to run, a popup window appears and you have to click "Run" to run it. This is two clicks to run a tool.
Request to solve via two complementary approaches:
1. If you click a Tool to run it, then it should run if there are no other options needed (ie, no "Next" button that could prompt for other settings).
A similar behavior is already possible with Actions, where there is a one-time Confirmation pop-up that says "Start action xxx?" with a "Don't show this dialog again." check box.
2. Regardless of whether there are optional "Next" options, allow to double-click on the Tool in the Action Panel to indicate to run it without a popup. A single-click would still behave as it does currently.