Three things on one page: patterns from your data (compare what worked vs what dead-ended), critique a draft you paste in, and a template library for the prompts you keep reusing. Everything runs locally on heuristics; the "deepen with Claude" button uses your Anthropic API key when you want a sharper read.
Heuristics sorted by how strongly they discriminate the two corpora. Big positive delta = your successful prompts have this much more often than your dead-ends; that's a signal to repeat the habit. Big negative delta = the opposite, a habit to drop.