What does AI citation verification mean in Legion?
It means a specific set of checks that Centurion runs when you ask, or when you click a tile that asks. Nothing in the drafting workflows calls CourtListener on its own. When Legion drafts a memorandum of points and authorities, the drafting prompts forbid inventing a citation and leave a [verify] marker on any authority that is missing or known only second-hand. The check happens when you ask Centurion to find authority, test opposing counsel's cases, or click "Verify every authority" on an MPA draft.
The checks are three verbs:
- Find. Search published opinions in CourtListener by party, subject, or phrase, narrowed by court and date.
- Confirm. Look up each reporter citation and return one of three verdicts: verified, not found, or not checked.
- Read. Pull the full text of the opinion and quote only from it, with the passage highlighted in a viewer you can open.
And one verb it does not do: validate. No subsequent-history check of any kind.
How does Legion find cases in CourtListener?
CourtListener is the Free Law Project's open database of court opinions. Centurion's search tool runs a full-text and case-name search of published opinions there, narrowed by a court identifier (the California Supreme Court, the Courts of Appeal, a federal circuit) and a decided-after date. Each search returns up to twenty hits with the case name, its citations, the court, the date filed, and a short snippet, and every hit opens in the in-app case viewer. Statutes are excluded; those are read on the web, with a limit covered below.
The web is the second step, not the first. If CourtListener returns nothing, the tool tells the model to reword the query and only then search the web. A case that turns up only on the web must be labeled "web-sourced" and "not CourtListener-verified" in the answer.
How does Legion confirm an AI case citation exists?
The citation tool takes a block of text, parses out every reporter citation in it, and looks each one up through CourtListener's citation lookup. It returns one verdict per citation:
- Verified. One opinion sits at that citation. The verdict carries the case name and a link to the opinion. If several opinions match, the citation is reported as real but ambiguous, and the model has to resolve it before relying on it.
- Not found. No opinion exists at that citation in CourtListener.
- Not checked. The reporter was not recognized, too many citations were packed into one request, or the lookup returned another status. "Not checked" is not a pass.
The tool reads reporter citations, not case names, so a wrong name on a real citation is caught at the reading step. And the verdict is on existence only. The prompt text that governs the tool says so in capitals: "EXISTENCE IS NOT VALIDITY." A citation that nobody can find, in CourtListener or on the web, stays out of the work product, even when the user insists the case exists.
In chat there is a second check that runs in code, not in the prompt. Every case Centurion cites in an answer carries a chip that opens the opinion. Before the answer reaches you, a server-side check compares each chip against the CourtListener results returned in that conversation. A chip naming a case that was never looked up fails, and the model gets one rewrite. If it fails again, the offending chips are shown as plain brackets instead of links.
How does Legion read the opinion before it quotes it?
Confirming that a citation exists says nothing about what the case holds. So the third verb is reading, and the rule is that any language Centurion quotes must come from the opinion's own text. The research procedure has the model read the cases it relies on in full, not the headnote or the snippet.
When you click a case, the viewer shows the case name, parallel citations, the court and date, a precedential-status badge, a count of how many times CourtListener records it being cited, the opinion text, and a "View on CourtListener" link. Where the quoted passage can be found in the text, the viewer opens with it highlighted. Where it cannot, the viewer opens at the top.
One limit on reading: the tool reads only the lead opinion, not concurrences or dissents. If a brief relies on a dissent, open that one yourself. The same discipline applies to the record: when Centurion relies on a document in the matter, it cites the page, and the line on line-numbered transcripts, and the cite opens the document at that spot.
On a memorandum of points and authorities, reading becomes a one-click pass. The "Verify every authority" tile on the MPA drafting page has Centurion take every authority flagged [verify] or not among your uploads, read the full opinion, and check that the case exists at the cited place, that it holds what the brief says rather than saying it in dicta, that every quotation matches word for word, that every pin cite lands where page markers exist, and that every sentence mentioning the case is accurate. Statutes and rules are checked against official text found on the web. It fixes the brief in place and removes the marker; a citation that cannot be found comes out of the draft. The pass ends with a report stating that subsequent history was not checked.
What Legion does not check: whether the case is still good law
Centurion does not check subsequent history. It does not know whether a case was reversed, whether a Court of Appeal opinion was depublished by the Supreme Court, whether a later panel declined to follow it, or whether a statute it construed has been amended. The "Cited N times" badge in the viewer is a raw count from CourtListener, not a treatment analysis. Legion does not use CourtListener's citation-network data, and CourtListener has no citator.
So a verified citation means exactly this: an opinion exists at that place in the reporter, Centurion read it, and the quoted language is in it. Whether you can still rely on it is a question for KeyCite, Shepard's, or your own read of the subsequent history. Centurion says so at the end of every research answer and verification pass, and the Centurion page says so as well.
AI hallucinated citations and sanctions in California: Noland, Cervantes, and SB 574
Noland v. Land of the Free, L.P. (2025) 114 Cal.App.5th 426 is California's first published opinion on AI-fabricated citations. Twenty-one of the twenty-three quotations in appellant's briefs were fabricated. The court imposed a $10,000 sanction, referred counsel to the State Bar, and ordered the opinion served on the client. It also denied respondent its fees, because respondent's counsel failed to detect and report the fake citations. The duty ran in both directions.
In Cervantes v. Bianco (Cal. Sept. 24, 2026, S295866), a brief to the California Supreme Court misquoted a 1989 decision and misstated its holding. The court wrote, "We disapprove of the improper use of artificial intelligence tools," and referred counsel to the State Bar. Note what went wrong: the case was real. The quotation and the holding were not. A tool that confirms existence and stops would have passed that citation. A tool that opens the opinion with the quote highlighted catches it, if the attorney looks. Damien Charlotin's database of AI hallucination cases stood at 2,184 worldwide on October 10, 2026, 1,492 of them in the United States.
SB 574 (Stats. 2026, ch. 858) was signed September 30, 2026 and takes effect January 1, 2027. It adds Business and Professions Code section 6068.1 and amends Code of Civil Procedure section 128.7. Attorneys may not delegate the practice of law to generative AI, must take reasonable steps to verify its output and correct hallucinations, and may not file papers containing citations the responsible attorney has not personally verified. Firms are jointly responsible. Commentators disagree on whether the enacted text also requires disclosing AI use to the court; read the chaptered text before relying on either view.
The State Bar's 2026 Practical Guidance, approved May 14, 2026, says the same in ethics terms: candor cannot be delegated to AI, no document goes to a court without attorney review and approval, and for agentic tools, "the greater the system's autonomy, the stronger the oversight obligation." Our guide to ChatGPT for lawyers covers the competence and confidentiality rules, and how small firms can adopt AI safely covers the firm policy behind them.
Personal verification under SB 574 means you, not the tool, confirmed the citation. Centurion's part is to make that fast: the verdict, the opinion in a viewer, the passage highlighted. Your part is to open it, read the passage in context, and run the treatment check in a citator before filing. A motion built on a reversed case fails the same way one built on an invented case does, and the discovery sanctions guide shows how little patience California courts have for either.
What CourtListener and Centurion do not cover
These are the gaps, in the words the code uses.
- CourtListener's coverage has holes. The tool's own description names them: "very recent opinions, some state appellate content, unpublished decisions." That is why the web is the second step and why web-only cases carry the "not CourtListener-verified" label.
- Statutes come from the web, and the official California site cannot be fetched. Centurion reads code sections and rules through web fetches, and the Legislature's site, leginfo.legislature.ca.gov, refuses them. Statutory text comes from a secondary source; the check against the official text is yours.
- No Bluebook validator. Citation format comes from the prompts. No code checks it.
- Only the lead opinion is read. Concurrences and dissents are not.
- Quotation matching is a reading discipline, not a code check. The viewer's highlight is the evidence you check it against.
- Nothing runs on its own. The drafting workflows never call CourtListener. Centurion checks when you ask or when you click a tile.
If a competing product tells you its citations are verified, ask which of these it covers and how. Our comparison of Legion with Harvey, Briefpoint, AI.Law, and the other legal AI platforms applies the same questions to each.
Frequently asked questions
Does Legion verify citations automatically?
No. The drafting workflows do not call CourtListener. A generated draft leaves a [verify] marker on any authority that is missing or known only second-hand, and the check runs when you ask Centurion in chat or click a tile such as "Verify every authority." The one check that runs unasked is in chat: a case chip that was not looked up in that conversation is rejected before the answer reaches you.
Can Legion tell me if a case is still good law?
No. Centurion confirms that an opinion exists at the citation and reads what it says. It does not check reversal, depublication, or negative treatment, and it says so at the end of each answer. Run the treatment check in KeyCite or Shepard's, or read the subsequent history yourself, before filing.
What does "not CourtListener-verified" mean?
The case was found through a web search rather than in CourtListener, so the existence check and the opinion reading did not run against CourtListener's copy. Treat it as a lead to confirm from the primary source, not as an authority ready to cite.
Does this satisfy SB 574?
Not by itself. SB 574 puts the duty to personally verify every filed citation on the responsible attorney, not on a tool. Centurion makes that quick: each citation comes back with a verdict, a link, and the quoted passage highlighted in the opinion. Open it, read it, and check its treatment, and you have done what the statute asks. File the verdict without opening the case and you have not.
How is this different from KeyCite or Shepard's?
They answer different questions. KeyCite and Shepard's tell you how a case has been treated since it was decided: reversed, overruled, distinguished, questioned. Centurion tells you whether the case exists, what it says, and whether the brief quotes it accurately, and it finds cases you do not yet have. Legion does not replace a citator. It gets you to the opinion with the passage highlighted and leaves the treatment check to the one you already use.
Take the next step
Every citation Centurion returns comes with a verdict, a link, and the opinion open to the quote. The treatment check and the signature stay with you. Try Legion on your next brief and see what the check looks like on your own authorities.
