Your prompt worked on Tuesday. On Thursday it works a little less — not enough to break, enough for a user to notice in two weeks. No ordinary test catches it, because there is no correct output to compare against, only a better or a worse one.

digline gives you an approved reference — the baseline — and on every change tells you whether you are below it: which case, which check, by how much.

The baseline is a JSON file in your repository, so it goes through code review and it rolls back with git. No server, no account, no network call you have not configured yourself.

pip install digline digline-anthropic

$ digline compare --suite suite.py --run latest
4 checks got worse compared with the reference. Every case could be judged. 1 case is suspended. The configuration is the same as the reference.

how-do-i-return · latency_budget · Score fell from 0.816327 to 0.650407.
how-do-i-return · regex · Went from passing to failing (1.000000 → 0.000000).
is-it-waterproof · latency_budget · Score fell from 0.816327 to 0.650407.
where-is-my-order · latency_budget · Score fell from 0.816327 to 0.650407.