An example from my experience.

Due to one of these civil law agreements.

We attained an enforceable undertaking based on the contract here.

Then we began proceedings to convert that to whatever the same thing was over there.

Which is when the other parties legal representation decided that it was a real threat and they settled.

You can take the judgement to a US court and it will be a simplied process. As long as it is a "normal" country like spain it shouldnt be a problem (if the court was say an Iranian court it might be more difficult).

Most courts will see a contract from anywhere and enforce it (Super Generally)

Most courts will see a contract + an enforceable undertaking from the country whose laws it was signed under and see that as roughly enforceable.

Doesnt mean always.

Might be a pain. If they have any EU presence, it'd be easier.

Without agreements you go ahead and win your local case and then hope that the contract is enforceable in their country.

Thing is torts are very similar all over the place. Like if you are a former british colony your laws are usually roughly compatible. Most countries dont have a "contract was signed overseas fuckem" law. But some do.