Define rattle?
These are direct injected and the injector noise sounds kinda like a diesel at idle.
These are also known for clogging up oil pump screen(which some cases manifesting around your mileage) so this is very important.

 

Sounds expensive

 

Yeah, it depends on what you mean by rattle. Constant clicking or tapping sounds are probably just the injectors as already mentioned but if it's a metallic rattle then maybe your turbo is about to fail or something else concerning. Ecoboost engines are wonderful when they are running well but nightmarish when something goes mechanically wrong.
Take it to a Ford dealer as they will know exactly what it's supposed to sound like. Or find someone else with the same 1.0L Ecoboost to compare it with. Maybe a Youtube video might help.

 

I have a 17' with the 1.0 Eco boost, mine rattles at idle as well, but it's the heat shield on the turbo. open the hood and check yours.

 

Can confirm, mine does this. Thought it was the turbo, but the multi piece heat shield just rattles at certain RPMs

 

My Dad had a '15 with 120k+ miles when it got totaled. It always ran quietly. Definitely take a look and make sure it's not something serious.

 

I will say that even the 2 liter idles pretty bad sometimes. It feels like the engine is starved of fuel for trying to be so efficient. Even though your car has 63,000 miles or kilometers, for being a 2012, I would try roughing it up a little bit with the gas pedal. Sometimes, these cars need to burn off carbon deposits being that it is a gdi engine, and after ~5000 miles of doing that, my car is idling significantly better. If it isn’t the exhaust shield for your turbo rattling, I’d give this a shot👍 You could also inspect your motor mounts for damage/wear because it’s apparent this car wasn’t driven a lot and has done a lot of sitting since 2012

 

It is normal to rattle on idle for the first 5 mins until it gets heated, i think it is the valves and the rich mixture