About Hallucination Shield
Why this exists
As of Q1 2026, US courts have imposed more than $145,000in attorney sanctions over fabricated AI-generated case citations. Damien Charlotin's public AI-hallucination database tracks 1,455+ documented cases and rising. In April 2026, an Oregon federal judge imposed $110,000 on a single attorney — the largest such sanction on record — for filing a brief with 23 fabricated citations and 8 invented quotes.
Hallucination Shield is the seatbelt. Paste your brief, get back a per-cite verdict and a court-ready paper trail. Built in a day, free forever, open source under MIT.
How it works
- We parse every citation in the brief (cases, USC, CFR, secondary sources) with regex and a Claude fallback for ambiguous shapes.
- For each cite, we query CourtListener (v4 REST API), GovInfo, and Justia as fallback. We pull the full opinion or statute text when available.
- We fuzzy-match every quoted passage from the brief against the source text to catch invented quotes.
- We ask Claude whether the cited authority actually supports the proposition asserted in the surrounding sentence — catching “real cite, wrong holding” errors.
- We render a Brigandi Shield Report PDF: per-cite verdict table, full reasoning log, Rule 1.1 attestation block, and a SHA-256 hash of the input for chain of custody. We also generate a standing-order disclosure cover sheet so you can attach the report to your filing.
What we do not do
- We do not store your brief. The verification runs against the text you submit and returns the report. Nothing is retained server-side after the request completes.
- We do not replace your independent verification. ABA Model Rule 1.1, Rule 3.3, and California's 2026 verify-every-output amendment all require you to confirm citations. This tool assists; it does not substitute.
- We do not give legal advice. We are software, not a lawyer.
Open source
MIT license. Code on GitHub at sboghossian/hallucination-shield. Issues, PRs, and forks welcome. If you build a vertical fork (immigration, family, IP), file an issue so we can link to it.