It would probably be better for usability to just have the tool on the front page. The first two steps of the tutorial - "Enter your text." and "Submit to Nitpi

It would probably be better for usability to just have the tool on the front page. The first two steps of the tutorial - "Enter your text." and "Submit to Nitpicker." - will already be clear to anyone who has used a few web forms. You could then include a hint on the Analyze step that one can click on the issues to pop up the menu. This would lower the barrier to using the tool, and reduce the amount of text and exposition new users have to slog through.