Can't you just ask GPT to give you a summary? Here's my prompt for 3.5, it's not very sophisticated.

  System: You are a helpful AI assistant who follows instructions to the letter. You will generate a summary of the article.
  Article: {ARTICLE}
  User: Summarize the previous text in one paragraph. Include as many topics as possible, make every word count. Create only one single summary and stop once you are done.