Hi @emadg ,
I don’t think language tools is best way to go here, because language tool will just check grammer and grammer does not predict wheather this sentence is complete or not. Here are the rules that are implemented in Language tool, you can check if there are any rules which will help you to classify a sentence as complete or not.
https://community.languagetool.org/rule/list?sort=category&order=asc 19
For ML Approach, I think you can try using a Language model, You can trying looking for things which end a sentence and find probaibily of those words like (Punctuations, conjuction words) in the end. Lesser probability means very less chances that sentence will end there.
PS: I will add If I found a concreate method to solve this.