# gutcheck 0.1.0: ask a buyer persona where to look gutcheck shows a Workers AI model a screenshot or a design plan with a buyer persona and prints probabilities for where to look. Four commands, a markdown persona file, about $0.0002 a check, one cargo install line. You have a page, or a plan for a page, and you want to know where a particular buyer would stop reading before you spend a person's time on it. gutcheck 0.1.0 does that with one command: it shows a model your screenshot and a persona you wrote, and prints the probabilities that this person feels the page is for them, trusts it, wants to try it, finds it polished or is confused.[1] The numbers tell you where to look and never approve a design. This is what each command does, what a run printed, what it cost and how to install it. ## What does each command do? `gutcheck check shot.png` shows Clef-flash a screenshot and a persona. For each persona it prints six things: for me, trust, try, polish, confused, and the feeling the person has first.[1] Pass more than one screenshot, `--model clef` for the larger model (the home page, onboarding, a sales page), or `--repeat N` for the mean and spread over N answers per persona.[1] `gutcheck directions directions.md` scores plans that are still words. Each `## name` heading in a markdown file is one direction, and every persona scores every direction with the larger Clef model. The score is try plus remember plus trust minus confused, averaged over the buyers.[1] `gutcheck polish shot.png parts.json` asks Clairic for a 0-10 polish estimate for each named part of a screenshot. `parts.json` names the parts, for example `{"headline": "the big first sentence"}`. Clairic samples, so its ranges move a point between runs, and the output gives a median with a 10th to 90th percentile range.[1] `gutcheck ask` sends your own question schema to a model with your own state and image and prints the raw answers.[1] `gutcheck status` shows the month's spend against the cap.[1] `--json` prints rows for other programs, and `--parallel N` sets how many calls run at once (the default is 4).[1] ## What did a run print? We ran the example persona from the repository on a 390-pixel-wide screenshot of one of our draft pages. ``` gutcheck check 01-first-390-light.png --persona try-1-example.md persona for me trust try polish confused feels first try-1-example 0.47 0.50 0.35 0.25 0.19 relief (0.11) ``` Then we scored two plans for a trade's home page. The plans are one sentence each: one opens on a price range and a phone number with the free-quote button under it, the other opens on a photo gallery with the phone number in the footer. ``` gutcheck directions directions.md --persona try-1-example.md direction score for me trust try remember confused Quote first 0.60 0.25 0.28 0.24 0.24 0.15 Gallery first -0.44 0.09 0.07 0.05 0.11 0.66 ``` And `gutcheck polish` on the same screenshot with one part, a headline, printed `7 (4-9)`. ## What is a persona file? A markdown file, written in the second person, that starts "You are". The whole file is sent to the model, so it should describe the person and nothing else.[1] The example in the repository reads: "You are Sam Okafor. You run a four-chair hair salon in a mid-sized town and have for nine years. You book by phone and Instagram, you are on your feet all day, and you look at websites on your phone between clients."[3] gutcheck finds personas in `docs/personas/` from the current folder upward: `try-*.md` files are buyers, and `wont-*.md` files are people who would not buy, which `check` shows only as their average "for me". Use `--persona FILE` or `--personas-dir DIR` to point somewhere else.[1] ## What does it cost? The three runs above moved gutcheck's own month total from $8.8323 to $8.8329: about $0.0002 for the one `check`, and $0.0004 for the `directions` and `polish` runs together. Each run used one persona. The price is Cloudflare's, per million input tokens: $0.038 for Clef-flash, $0.24 for Clef and $0.10 for Clairic. Responses carry no token counts, so gutcheck estimates a call from the text length at 3.5 characters a token and 2,000 tokens for an image.[1] The cap is US$10 a month unless you set one. `GUTCHECK_CAP_USD=25` raises it, or put `per_month_usd = 25` under `[gutcheck]` in `~/.config/gutcheck/budget.toml`. Every call is logged to `~/.local/share/gutcheck/calls.jsonl`, and a run that would cross the cap is refused with exit code 3.[1] ## How do I install it? You need Rust, a Cloudflare account (Workers AI has a free allowance) and, only for screenshots over 4 MiB, ImageMagick.[1] ``` cargo install --git https://github.com/mackenziebowes/gutcheck export CLOUDFLARE_API_TOKEN=... export CLOUDFLARE_ACCOUNT_ID=... gutcheck check shot.png --persona examples/personas/try-1-example.md ``` The token needs Workers AI permission, or you can run `wrangler login`. The account id can also go on the first line of `~/.config/gutcheck/account_id`.[1] It is MIT licensed, and the release is v0.1.0.[2] ## How should you read the numbers? They do not predict whether a design will be approved. In an earlier test of ours (hub ticket 1753), Clef-flash scored 29 of Mackenzie's design reviews on eight criteria, and the combined score ordered approvals no better than always predicting "approve": 18 to 20 of 29 right, against 20 of 29. Read the numbers as a map of where to look, and look. The order of the questions is fixed, and a test in the repository pins it, because the model reads them in the order given.[1] Costs are estimates, and the log is the only record of them. ## What should your agent bring to you? A persona for your own buyer, in a markdown file, and one screenshot of the page you are about to show someone. Run `check`, read where "confused" is highest, and look at that part of the page first. If you're scoring designs with personas and want to compare notes, I'd like to hear how: mackenzie@mackenziebowes.com or [@_mackenziebowes](https://x.com/_mackenziebowes). ## Sources 1. gutcheck, MIT licence, Mackenzie Bowes: README and source at v0.1.0. 2. gutcheck v0.1.0, published 2026-10-28T02:07Z. 3. gutcheck, examples/personas/try-1-example.md at v0.1.0. --- Published 2026-10-27. Web page: https://www.mackenziebowes.com/posts/gutcheck-0-1-0-ask-a-buyer-persona-where-to-look