First, we need the .ai files from Data.sga. At the bare minimum you will need the default_skirmish.ai, but if you want to overwrite all the standard .ai files you will need the skirmish.ai and tactics.ai as well. I would recommend just extracting the entire .ai folder
the default_skirmish.ai only contains :
and it's quite bare. You can add your own settings and economy overrides just fine, but beware if you looked at the other .ai personality files for inspiration because they contains mistypes. In particular, the basic_personality_template.ai uses Game_GetLocalPlayer() which is incorrect since it refers to the human player. It should be AI_GetPlayer().
If you notice it imports skirmish.ai. Now, if you want to modify skirmish.ai and tactics.ai you can only copy and paste the whole skirmish.ai to your personality file replacing the import. And if you notice the skirmish.ai itself it imports tactics.ai as well as util/debug.ai and ai-view.ai. We're only interested in the tactics.ai so replace the import line in skirmish.ai with the whole tactics.ai. Leave the debug and ai-view functions alone as they only contain debugging stuff.
So now you have one big .ai file, put it somewhere in your mod folder and create a folder and burn file like these (example from my A.I mod) :
Note that the folder structure has to be exactly like this. No you can't put your own skirmish.ai to the \data\ai folder, it will not be recognized by CoH2 although it can be built. We only have access to the \data\ai\personality folder for a tuning pack, hence the whole copy and paste thing.
And finally, don't forget to change the ai_personality attributes :
Congrats, now you can use SCAR scripting (albeit very limited in scope) in a tuning pack. And change or add all the TacticFilter stuff.