It’s called EditMinion, and it’s a website. You copy some of your deathless prose into it, click Edit, and it displays a “report card,” including a markup of your text.
Now I’m a firm advocate of thinking about what you write, and of having other humans look at your writing as well. But I put some of this humble blog into EditMinion, and I got a high grade, so I have to like it at least a little. Just as with Microsoft’s grammar checker, running your creation through one of these things can be a good source of ideas, though you will most likely disagree with a lot of the program’s judgement calls. I don’t think they’ve invented software that can evaluate poetic license yet. Automated editors tend to find things that share two characteristics: they find simple solecisms, and things that are so common you don’t notice them. That’s worth something. Here’s what the site looks like: