{"id":155654,"date":"2026-07-01T05:25:51","date_gmt":"2026-07-01T13:25:51","guid":{"rendered":"https:\/\/xira.com\/p\/2026\/07\/01\/those-wl-citations-are-an-open-invitation-to-ai-hallucinations\/"},"modified":"2026-07-01T05:25:51","modified_gmt":"2026-07-01T13:25:51","slug":"those-wl-citations-are-an-open-invitation-to-ai-hallucinations","status":"publish","type":"post","link":"https:\/\/xira.com\/p\/2026\/07\/01\/those-wl-citations-are-an-open-invitation-to-ai-hallucinations\/","title":{"rendered":"Those \u2018WL\u2019 Citations Are An Open Invitation To AI Hallucinations"},"content":{"rendered":"

Lawyers continue to file hallucinated cases, which is, frankly, kind of an accomplishment at this point. Legal tools exist that guard against such hallucinations and even more tools exist to double check to make sure no hallucinations slipped in there. And then, of course, there\u2019s being an actual lawyer<\/em> and proofreading your work before filing it. <\/p>\n

Even though the blame rightly falls on the attorneys failing to check their cites, there\u2019s still room for other actors to help save these lawyers from themselves.<\/p>\n

During last week\u2019s Legaltech Week<\/a> roundtable, a February blog post<\/a> by law librarian Shay Elbaum was brought to my attention that deserves some more attention. The post discusses a point raised in Flycatcher Corp. v. Affable Avenue<\/em>. It\u2019s an otherwise bog standard AI hallucination sanction case, except the lawyer involved made the argument that when a generative AI tool invents a citation in a proprietary format, it makes it difficult to verify it without access to the proprietary source.<\/p>\n

In other words, when the AI spits out \u201c2022 WL 4637582,\u201d or \u201c2024 LEXIS 2847243,\u201d there are lawyers out there who can\u2019t easily check that. As Elbaum notes, \u201cnot only is it difficult for you to read the case, but it\u2019s also difficult for you to even be sure it\u2019s a real case.\u201d The attorney in this case, as it happens, did have access to Westlaw, so this argument did not go over well. But it\u2019s nonetheless an interesting wrinkle. <\/p>\n

Lawyers shouldn\u2019t include cases they can\u2019t verify, but consider that we now have judges sanctioning lawyers for simply not catching the other side\u2019s mistakes. A cite in an opposing brief that the lawyer can\u2019t verify leaves those who did nothing wrong vulnerable just because they aren\u2019t subscribed to the big databases.<\/p>\n

\n

On a quick review of the latest fabricated citations in\u00a0Damien Charlotin\u2019s database<\/a>, most of the recent filings with fabricated citations included at least one fake citation with the format \u201c2022 WL 4637582,\u201d supposedly pointing to an unpublished case available on Westlaw. (I\u2019ll call these \u201cWL citations\u201d in the rest of this post.) I didn\u2019t find any hallucinated citations with the equivalent Lexis format for unpublished cases, but my review was far from thorough and I assume they exist.<\/p>\n<\/blockquote>\n

This isn\u2019t a knock on Westlaw or Lexis, but their proprietary formats make them more vulnerable to ending up in embarrassing hallucination stories. When a brief from opposing counsel cites a phantom F.3d case, anyone with a free database can catch it in 30 seconds. When the same brief cites a phantom WL case, the lawyer on the other side \u2014 the solo, the legal aid attorney, the self-represented litigant who couldn\u2019t swing a Thomson Reuters subscription if their docket depended on it \u2014 has no move.<\/p>\n

Presumably both major legal publishers would say, \u201cthey could buy a subscription,\u201d so let\u2019s agree to roll our eyes and then move on to some entirely obvious solutions that have nonetheless not been implemented: <\/p>\n

\n

If Westlaw doesn\u2019t want the WL citations to become red flags for potential hallucinations, it needs to provide a method for everyone to verify these citations. Lexis, too; I\u2019m just picking on Westlaw more because their database-specific format is hallucinated more frequently. And courts can act, too, without even needing to directly regulate AI use. Federal Rule of Appellate Procedure 32.1(b) already requires attorneys citing unpublished cases to provide copies of the cases with their filings. Adding a similar requirement to the Federal Rules of Civil Procedure and their state equivalents, or to local rules and standing orders, would even the playing field and reduce hallucinations in filings.<\/p>\n<\/blockquote>\n

I\u2019d go further than just a checker and say they should allow anyone to read a raw unpublished decision if the user enters the precise citation they\u2019re looking up. It doesn\u2019t give away the data moat to let people see the case based on entering a precise citation. The real value of these databases is in researching concepts, not calling up specific documents. Strip the result of key cites if necessary\u2026 but just give them access to the opinion. <\/p>\n

There may have been a day where Thomson Reuters and LexisNexis made money off gatekeeping unpublished opinions, but that\u2019s not the cash cow in a world where they\u2019re selling state-of-the-art AI research tools. It\u2019s not worth becoming the common link in a bunch of hallucination cases just to jealously guard some Eastern District of Missouri ruling on a random motion in limine. A free public lookup would fix that and what the publishers lose is basically a rounding error.<\/p>\n

As for rules requiring lawyers to attach copies of unpublished opinions, there are a few districts doing that, but it should be universal. The elegance is that a rule forcing lawyers to attach copies of the case would force them to confirm the case is real in the first place. Maybe if everyone did that with all their cases, we wouldn\u2019t be in this mess. And, maybe more to the point, the rule must be universally enforced. Because Elbaum notes that the Middle District of Pennsylvania has such a rule now and:<\/p>\n

\n

I took a peek at recent filings in the Middle District of Pennsylvania and found plenty of citations to unpublished opinions, but no attached copies.\u00a0<\/p>\n<\/blockquote>\n

Swing and a miss. But that\u2019s why we need a belt and suspenders approach here. <\/p>\n

For two years we\u2019ve treated hallucinations as the personal failings the lawyers. Because they are. But one of these days, those mistakes are going to work their way into the system in the form of rubberstamped rulings that get repeated as precedent. So there\u2019s an obligation for all of us to save these folks from themselves before they make everything worse for everybody.<\/p>\n

\n

\"Headshot\"Joe Patrice<\/a>\u00a0is a senior editor at Above the Law and co-host of Thinking Like A Lawyer<\/a>. Feel free to\u00a0email<\/a> any tips, questions, or comments. Follow him on\u00a0Twitter<\/a>\u00a0or Bluesky<\/a> if you\u2019re interested in law, politics, and a healthy dose of college sports news.<\/em><\/strong><\/p>\n

The post Those \u2018WL\u2019 Citations Are An Open Invitation To AI Hallucinations<\/a> appeared first on Above the Law<\/a>.<\/p>\n

\"\"<\/figure>\n

Lawyers continue to file hallucinated cases, which is, frankly, kind of an accomplishment at this point. Legal tools exist that guard against such hallucinations and even more tools exist to double check to make sure no hallucinations slipped in there. And then, of course, there\u2019s being an actual lawyer<\/em> and proofreading your work before filing it. <\/p>\n

Even though the blame rightly falls on the attorneys failing to check their cites, there\u2019s still room for other actors to help save these lawyers from themselves.<\/p>\n

During last week\u2019s Legaltech Week<\/a> roundtable, a February blog post<\/a> by law librarian Shay Elbaum was brought to my attention that deserves some more attention. The post discusses a point raised in Flycatcher Corp. v. Affable Avenue<\/em>. It\u2019s an otherwise bog standard AI hallucination sanction case, except the lawyer involved made the argument that when a generative AI tool invents a citation in a proprietary format, it makes it difficult to verify it without access to the proprietary source.<\/p>\n

In other words, when the AI spits out \u201c2022 WL 4637582,\u201d or \u201c2024 LEXIS 2847243,\u201d there are lawyers out there who can\u2019t easily check that. As Elbaum notes, \u201cnot only is it difficult for you to read the case, but it\u2019s also difficult for you to even be sure it\u2019s a real case.\u201d The attorney in this case, as it happens, did have access to Westlaw, so this argument did not go over well. But it\u2019s nonetheless an interesting wrinkle. <\/p>\n

Lawyers shouldn\u2019t include cases they can\u2019t verify, but consider that we now have judges sanctioning lawyers for simply not catching the other side\u2019s mistakes. A cite in an opposing brief that the lawyer can\u2019t verify leaves those who did nothing wrong vulnerable just because they aren\u2019t subscribed to the big databases.<\/p>\n

\n

On a quick review of the latest fabricated citations in\u00a0Damien Charlotin\u2019s database<\/a>, most of the recent filings with fabricated citations included at least one fake citation with the format \u201c2022 WL 4637582,\u201d supposedly pointing to an unpublished case available on Westlaw. (I\u2019ll call these \u201cWL citations\u201d in the rest of this post.) I didn\u2019t find any hallucinated citations with the equivalent Lexis format for unpublished cases, but my review was far from thorough and I assume they exist.<\/p>\n<\/blockquote>\n

This isn\u2019t a knock on Westlaw or Lexis, but their proprietary formats make them more vulnerable to ending up in embarrassing hallucination stories. When a brief from opposing counsel cites a phantom F.3d case, anyone with a free database can catch it in 30 seconds. When the same brief cites a phantom WL case, the lawyer on the other side \u2014 the solo, the legal aid attorney, the self-represented litigant who couldn\u2019t swing a Thomson Reuters subscription if their docket depended on it \u2014 has no move.<\/p>\n

Presumably both major legal publishers would say, \u201cthey could buy a subscription,\u201d so let\u2019s agree to roll our eyes and then move on to some entirely obvious solutions that have nonetheless not been implemented: <\/p>\n

\n

If Westlaw doesn\u2019t want the WL citations to become red flags for potential hallucinations, it needs to provide a method for everyone to verify these citations. Lexis, too; I\u2019m just picking on Westlaw more because their database-specific format is hallucinated more frequently. And courts can act, too, without even needing to directly regulate AI use. Federal Rule of Appellate Procedure 32.1(b) already requires attorneys citing unpublished cases to provide copies of the cases with their filings. Adding a similar requirement to the Federal Rules of Civil Procedure and their state equivalents, or to local rules and standing orders, would even the playing field and reduce hallucinations in filings.<\/p>\n<\/blockquote>\n

I\u2019d go further than just a checker and say they should allow anyone to read a raw unpublished decision if the user enters the precise citation they\u2019re looking up. It doesn\u2019t give away the data moat to let people see the case based on entering a precise citation. The real value of these databases is in researching concepts, not calling up specific documents. Strip the result of key cites if necessary\u2026 but just give them access to the opinion. <\/p>\n

There may have been a day where Thomson Reuters and LexisNexis made money off gatekeeping unpublished opinions, but that\u2019s not the cash cow in a world where they\u2019re selling state-of-the-art AI research tools. It\u2019s not worth becoming the common link in a bunch of hallucination cases just to jealously guard some Eastern District of Missouri ruling on a random motion in limine. A free public lookup would fix that and what the publishers lose is basically a rounding error.<\/p>\n

As for rules requiring lawyers to attach copies of unpublished opinions, there are a few districts doing that, but it should be universal. The elegance is that a rule forcing lawyers to attach copies of the case would force them to confirm the case is real in the first place. Maybe if everyone did that with all their cases, we wouldn\u2019t be in this mess. And, maybe more to the point, the rule must be universally enforced. Because Elbaum notes that the Middle District of Pennsylvania has such a rule now and:<\/p>\n

\n

I took a peek at recent filings in the Middle District of Pennsylvania and found plenty of citations to unpublished opinions, but no attached copies.\u00a0<\/p>\n<\/blockquote>\n

Swing and a miss. But that\u2019s why we need a belt and suspenders approach here. <\/p>\n

For two years we\u2019ve treated hallucinations as the personal failings the lawyers. Because they are. But one of these days, those mistakes are going to work their way into the system in the form of rubberstamped rulings that get repeated as precedent. So there\u2019s an obligation for all of us to save these folks from themselves before they make everything worse for everybody.<\/p>\n

\n

\"Headshot\"Joe Patrice<\/a>\u00a0is a senior editor at Above the Law and co-host of Thinking Like A Lawyer<\/a>. Feel free to\u00a0email<\/a> any tips, questions, or comments. Follow him on\u00a0Twitter<\/a>\u00a0or Bluesky<\/a> if you\u2019re interested in law, politics, and a healthy dose of college sports news.<\/em><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Lawyers continue to file hallucinated cases, which is, frankly, kind of an accomplishment at this point. Legal tools exist that guard against such hallucinations and even more tools exist to double check to make sure no hallucinations slipped in there. And then, of course, there\u2019s being an actual lawyer and proofreading your work before filing […]<\/p>\n","protected":false},"author":3,"featured_media":155592,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[16],"tags":[],"class_list":["post-155654","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-above_the_law"],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/xira.com\/p\/wp-content\/uploads\/2026\/06\/Headshot-300x200-OKbXCD.jpg?fit=300%2C200&ssl=1","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/posts\/155654","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/comments?post=155654"}],"version-history":[{"count":0,"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/posts\/155654\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/media\/155592"}],"wp:attachment":[{"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/media?parent=155654"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/categories?post=155654"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xira.com\/p\/wp-json\/wp\/v2\/tags?post=155654"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}