Sentence examples for cool with it from inspiring English sources

"cool with it" is a grammatically correct phrase and can be used in written English.
It is a colloquial expression that means being in agreement or comfortable with something. Example: "I'm cool with it if you want to go to the concert instead of the movies tonight." (This means the speaker is fine with the other person's suggestion.) "You can borrow my car, but are you cool with filling up the gas tank before returning it?" (This means the speaker wants to make sure the other person is okay with this condition before lending the car.).