Does the following passage contain a sentence fragment error?

He thinks he should probably cool it a little on the coffee before trying to write anything next time.

No, the passage does not contain a sentence fragment error. It is a complete sentence with a subject ("He") and a predicate ("thinks he should probably cool it a little on the coffee before trying to write anything next time").

No, the given passage does not contain a sentence fragment error. It is a complete sentence that expresses a complete thought.