How to add a AppleScript file to the Finder toolbar to execute the AppleScript

See if this works.

Download the Get first Finder Window Path BETA 10.9 automator action from from my blog : my_very_first_automator_action

The action returns the path of the front most finder window. It does not take any input from above actions. The post explains it all :-)

Create a new Application document in Automator and add the Get first Finder Window Path to it. Then just add you Run shell script after it.

Save as Application. And then do the drag and drop.

I would test it with your code but I do not have the python slideshow...

Note from Apple documentation in regard to Third party Actions.

Installing Actions When your action has been thoroughly debugged and tested, build a deployment version of the bundle (using the proper optimizations). Then create an installation package for the action (or add the action to your application’s installation package). The installer should copy the action to /Library/Automator or ~/Library/Automator, depending on whether access to the action should be system wide or restricted to the installing user.

Instead of installing your action separately, you can put it inside the bundle of your application, especially if the action uses the features of that application. When Automator searches for actions to display, it looks inside registered applications as well in the standard Automator directories. The advantage of packaging your actions inside an application is that you don’t need to create a separate installation package to install the actions. To install the actions, users need only drag the application to a standard location.

Action bundles should be stored inside the application wrapper at Contents/Library/Automator. Thus, if your action is MyAction.action and your application is MyApp.app, the path inside the application would be:

MyApp.app/Contents/Library/Automator/MyAction.action

You can either manually copy an action into this location (after creating the necessary subdirectories) or you have Xcode copy it using a Copy Files build phase. If you copy an action into an application bundle but the application is already installed on a system, you must get Launch Services to recognize that the application has new content to register (that is, the new action) by changing the application’s modification date. You can do this by entering the touch command in the Terminal application.

sudo touch /Applications/MyApp.app

Or you can rename the application in Finder to something else, change it back to the original name, and then launch the application once.

Updated Answer:

The code below it what I'd use to replace the original code offered as there appears to be a bug in AppleScript when using the do shell script command in the manner originally presented that isn't present went the code, in a representative manner, is run in a bash script in Terminal.

Note that anytimeopen for access is used, it needs to be coded to trap any errors and try and close the file, which this attempts to do. That said it is not necessarily then only error handling I'd employ and all coding answer I present are done so as proof of concept and the onus to write code employing reasonable error handing is yours to fulfill.

As coded, this will create the target file if it doesn't exist while adding the text to add to it and if it does exist, places the text to add as the top line of the target file.

set targetFilePathname to (POSIX path of (path to desktop as string) & "My Fruit Log.txt")

--    # set theTextToWrite to "This text will be written at the top of the file." & "\n"    
set theTextToWrite to "This text will be written at the top of the file." & "\n"
set theOriginalText to ""
try
    set theOriginalText to (read targetFilePathname) as string
end try
--    # set theTextToWrite to theTextToWrite & "\n" & theOriginalText
set theTextToWrite to theTextToWrite & "\n" & theOriginalText
try
    set referenceNumber to open for access targetFilePathname with write permission
    write theTextToWrite to referenceNumber starting at 0
    close access referenceNumber
on error eStr number eNum
    display dialog eStr & " number " & eNum buttons {"OK"} default button 1 with title "File I/O Error..." with icon caution
    try
        close access referenceNumber
    end try
    return
end try