Use a comma before ‘but’ if it connects two independent clauses (unless they are closely connected and short). (COMMA_COMPOUND_SENTENCE[1]) Suggestions: `, but` URL: https://languagetool.org/insights/post/grammar-what-are-compound-sentences/ Rule: https://community.languagetool.org/rule/show/COMMA_COMPOUND_SENTENCE?lang=en-US&subId=1 Category: PUNCTUATION