Stewart goes home is it a fragment or run-on or sentence

Stewart goes home is a complete sentence.

Explanation:

The traits of a complete sentence are:

A subject

A predicate

Now we can analyze the sentence. Stewart is our subject and goes is our predicate. In that case, we can look for the traits of a run-on sentence:

A longer sentence with two complete thoughts and no comma or coordinating conjunction.

Since "Stewart goes home" is not a run-on sentence, it is our final option. A complete sentence.