Finecomb: a private medical bill checker, built by AI agents
Paste a medical bill (or upload a PDF) and Finecomb flags possible issues to ask about: charges listed twice, totals that don't add up, charges dated after discharge, a bill above what your EOB says you owe, No Surprises Act gaps. Each finding shows why it was flagged, the lines involved, how to verify it, a confidence level, the dollars in question when it can compute them, and for rule-based findings the law or agency page behind it (checked 1 Oct 2026). It drafts a dispute letter and screens for charity care worth asking about.
Privacy: it is a static site. Parsing and every check run in your browser, and no server receives a bill. The live privacy test records 9 requests for a full check, all to the site itself, none carrying bill data, and the same 9 for a different bill.
How it was built: 11 Claude Code lanes, at most 3 at a time. Opus 5.5 did the research, spec, test bills, precision pass, integration, QA and publishing; Sonnet 5 wrote the data pipeline, rules engine, app, bill readers, letters and screener. 56 commits, 206 unit tests.
Accuracy, honestly: on 15 hand-made test bills whose answers were committed before the engine ran, 23 of 27 flags were right and it found 23 of 25 planted issues. The worst miss, a High-confidence claim against a provider whose bill wasn't uploaded, is fixed, and 4 checks ship capped at Low. Photo reading is beta, and PDFs can drop line descriptions; pasted text is the most reliable path. The 1.00 score on 300 generated bills only shows the engine agrees with its own spec, and /accuracy says so.
Code (MIT): https://github.com/useslop/finecomb
Possible issues to ask about, never promised savings. Not legal, medical or financial advice.