TL;DR: Courts are sanctioning filings with fabricated or misquoted authority. This guide compares 7 AI citation checkers US lawyers can run before filing, with LuMay Virtual Paralegal first for policy-gated review and redlined outputs.
An AI citation checker reviews the authorities in a legal document, flags invented or misquoted cases, checks pincites and treatment, and reports whether each authority supports the stated proposition.
Ranking criteria and disclosure: LuMay publishes this list and ranks its Virtual Paralegal first. We then compared check depth, proposition support, review outputs, workflow fit and source grounding, using vendor pages checked on 26 October 2026 (IST). No vendor paid for placement.
Quick Answer: LuMay Virtual Paralegal ranks first for policy-gated citation review with severity levels and redlined DOCX outputs. proofread.law is a fast paste-and-check tool. Clearbrief and BriefCatch work in Word. Quick Check, Lexis+ Brief Analysis and CoCounsel suit firms on those research platforms.
Why Pre-Filing Citation Checks Now Matter
BriefCatch notes that from January 1, 2027, California's SB 574 requires the attorney responsible for a filing to personally verify every citation. AI tools speed review; they do not replace that duty.
- What to check
- Existence: the case is real
- Accuracy: volume, page, pincite and quotes
- Support: the authority backs the proposition
- Including later treatment and negative history
AI Citation Checkers: Comparison Table
| Tool | Works in | Key checks | Best fit |
|---|---|---|---|
| LuMay Virtual Paralegal | Firm workflow, DOCX outputs | Citations, quotes, pincites, support, treatment | Firms needing review gates |
| proofread.law | Paste, PDF, DOCX, API | Fake cases, wrong volumes, misquotes, support | Fast pre-filing checks |
| Clearbrief | Microsoft Word | Fact-checking, hyperlinked citations | Litigators citing the record |
| BriefCatch | Microsoft Word | Editing and citation tools | Brief writing quality |
| Westlaw Quick Check | Westlaw upload | Warnings, quotations, table of authorities | Westlaw subscribers |
| Lexis+ Brief Analysis | Lexis+ | AI brief review | Lexis+ subscribers |
| CoCounsel Legal | Thomson Reuters suite | Westlaw-grounded AI assistance | Broad AI legal assistant |
1. LuMay Virtual Paralegal: Policy-Gated Citation Review
LuMay's Virtual Paralegal checks citations, quotes, pincites, proposition support, case treatment, later authority and regulatory changes against approved sources, then generates redlined DOCX files and exception reports.
- Strengths
- Issues graded Verified, Form, Material or Blocking
- Blocking issues prevent approval
- Authority audits and filing-readiness outputs
- Decision remains with supervising counsel
- Issues graded Verified, Form, Material or Blocking
- Deployment
- SaaS, your cloud or on-prem via deployment options
- Watch
- A firm workflow tool, not a free paste-in checker
Read our guide on how to verify AI-generated legal research citations, or explore the wider LuMay Legal Agent.
2. proofread.law: Fast Paste-and-Check
proofread.law cite-checks every case citation against 10 million opinions in seconds, flagging invented cases, wrong volumes, misquotes and whether the case supports the point.
- Best for: quick checks on AI-drafted or hand-drafted work
- Watch: it notes some citation classes are not checked
3. Clearbrief: Fact and Citation Checks in Word
Clearbrief brings AI fact-checking and hyperlinked citations into Word, uses the line "Cite facts, not fake cases," and was named a Legalweek 2026 winner.
- Best for: litigators tying briefs to the record
- Watch: focus is facts and evidence as well as case law
4. BriefCatch: Legal Writing Editor
BriefCatch, built by Ross Guberman, turns Word into a legal editing environment and reports 300+ firms, including 45+ Am Law 200.
- Best for: brief quality and style
- Watch: confirm citation-verification depth for your needs
5. Westlaw Quick Check: Brief Upload Report
With Westlaw Quick Check, you upload a brief and get recommendations for additional authority, warnings for cited authority, a quotation analysis and a table of authorities.
- Best for: Westlaw subscribers
- Watch: requires a Westlaw subscription
6. Lexis+ Brief Analysis: LexisNexis Brief Review
Lexis+ Brief Analysis is LexisNexis's AI legal brief review tool within Lexis+. Its product page loads dynamically, so confirm features in a demo.
- Best for: Lexis+ subscribers
- Watch: feature details need confirming with LexisNexis
7. CoCounsel Legal: Westlaw-Grounded AI Assistant
CoCounsel Legal is Thomson Reuters' AI legal assistant, with tools such as Deep Research grounded in Westlaw content.
- Best for: firms wanting a broad AI assistant
- Watch: not a dedicated pre-filing citation checker
How to Build a Pre-Filing Citation Workflow
- Run checks early
- Not the night before filing
- Grade issues
- Fix blocking issues before approval
- Keep a record
- Save the report with the matter file
- Get help designing it
- AI consulting can map review gates to firm policy
Next Step
Want citation review before every filing? Book a LuMay demo of the Virtual Paralegal on a sample brief.
