Every listing leaves clues. We read them.
A free checker built for mystery, thriller and crime authors. Paste your title, blurb, seven KDP keywords and categories, and see what's costing you readers, ranked by what to fix first.
No evidence yet.
Paste your listing, or try a sample to see how the checker works.
Five tools. One goal: more readers clicking "Buy".
Mystery blurb grader
Checks for the things mystery shoppers scan for: a named sleuth, a concrete crime, real stakes, and a closing question.
Open tool →Subgenre category finder
Kindle shelves for cozy, procedural, PI, historical, psychological, legal and crime fiction, checked against Amazon's live charts.
Open tool →7-keyword builder
Flags wasted characters, repeats, banned terms and title duplicates, with subgenre phrase ideas you can test.
Open tool →Subtitle generator
Genre-signalling subtitles like "A Small-Town Cozy Mystery (Book 1)", checked against KDP's 200-character limit.
Open tool →Open case study
We're running the tools on a real book, the founder's own, and publishing the before, the after, and the results.
Read the file →Guides
Plain-English guides: cozy mystery KDP categories, writing a mystery blurb, and choosing your 7 keywords.
Read →What the checker looks at
Clue to Cart™ runs a set of plain rules, the kind an experienced editor applies by eye. They come from KDP's own metadata help pages (keyword limits, words to avoid, title rules) plus widely shared blurb craft for genre fiction. It doesn't use AI and it doesn't send your text anywhere.
A score is a second pair of eyes, not a sales forecast. Good books break rules on purpose. If a rule doesn't fit your book, ignore it.
Frequently asked questions
Is Clue to Cart free?
Yes. Every tool is free to use with no sign-up or account.
Does Clue to Cart store or upload what I paste?
No. The tools run entirely in your web browser. Your title, blurb, keywords and categories are processed on your device and are not uploaded or stored. The only thing the site stores is your email address, if you join the newsletter list.
Who is Clue to Cart for?
Authors and publishers of mystery, thriller, suspense and crime fiction who sell on Amazon through Kindle Direct Publishing (KDP). The checks are tuned for those genres, so they are less useful for romance, fantasy or most nonfiction.
Does it use AI?
No. Clue to Cart applies plain written rules based on KDP's published metadata guidance and common genre-fiction blurb craft. The same input always gets the same result.
Is Clue to Cart affiliated with Amazon?
No. Clue to Cart is independent and is not affiliated with or endorsed by Amazon or Kindle Direct Publishing.
How current are the category suggestions?
The Kindle category paths were read from Amazon.com's public Kindle Best Sellers pages on October 17, 2026. Amazon changes categories over time, so always confirm a path in KDP's category picker before you use it. Print-book categories are not covered yet.
Will a higher score mean more sales?
Not necessarily. A score is a checklist result, not a sales forecast. Covers, price, reviews, ads and the book itself all matter too.
Join the list — first issue coming soon.
One real mystery listing, taken apart each week. Free. We'll store your email address and won't send anything until the first issue. How we handle your email.