ProofKit

ProofKit

Open pilot test: 50 fabricated + 100 real citations

Run on 6 November 2026 with the same engine as /check. Fabricated citations come from court decisions on AI-invented cases (AI Hallucination Cases database by Damien Charlotin, CC BY 4.0). Real citations: (R) US Supreme Court, UK Find Case Law, EUR-Lex; (M) a matched set of 50 real state and federal cites from the same kinds of reporters as the fabricated ones, sampled from the Caselaw Access Project (static.case.law). Every row has a signed receipt digest.

Results

  • Fabricated (50): flagged 30 (no such case / a different case at that cite); marked unverifiable (Westlaw-only, closed database) 14; no citation in the text 4; other 2; wrongly verified 0.
  • Real (50): verified 32; exists, name not compared 18; false alarms 0.
  • Real, matched to the fabricated set (50): verified 46; several cases share the cite or name not compared 3; could not check 1; false alarms 0.

Limits — read before quoting

  • Pilot, small sample (150 citations). The matched real set (M) covers the same reporters as the fabricated set; the first real set (R) is high courts only.
  • ProofKit checks that a case exists at the citation and that the name matches. It does not check whether the case supports the argument.
  • This test found bugs in ProofKit, and we fixed them before publishing: the first run flagged 15 fabricated cites and gave 2 false alarms; after fixes to reporter coverage and name matching — the numbers above.

All 100 rows

IDTruthCitationProofKit verdictReceipt
F01fabricatedWalker v. Huff, 60 S.W.3d 820, 826 (Tenn. Ct. App. 2000)exists — compare name by handf85f45ff71025ae0
F02fabricatedIn re State Street Bank and Trust Co. ERISA Litig., No. 07-cv-10907, 2009 WL 10260136unverifiable (closed database)0beb8e2a7fa918b8
F03fabricatedSEC v. Collins, No. 01-cv-3065, 2002 WL 31109065, at *4 (S.D.N.Y. Sept. 23, 2002)unverifiable (closed database)900ba8ff3ce3953e
F04fabricatedHurley v. Deutsche Bank Trust Co., 2011 WL 1103376 (S.D. Cal. 2011)unverifiable (closed database)1a9b1ebad84e7570
F05fabricatedCG v SSHD [2021] EWCA Civ 641unverifiable (closed database)7d72fde2630ba672
F06fabricatedNunes v. Texas, 2024 WL 1978793 (5th Cir. May 3, 2024)unverifiable (closed database)da28df259d286f22
F07fabricatedKatz v Heller, 2013 ABQB 275no citation in text4a00dae3a5392564
F08fabricatedRoe v. Planned Parenthood, 2020-Ohio-4863different case at this cite923dc8cc5ff2afab
F09fabricatedLowrey v. Eastaff, 860 A.2d 533 (Pa. Super. 2004)different case at this citea6407b41c61c8440
F10fabricatedCottman Transmission Sys., Inc. v. Metro. Pontiac GMC, Inc., 351 F. Supp. 2d 343, 347 (E.D. Pa. 2004)different case at this cite0b5a1219aa7fd607
F11fabricatedMcMahon v. RMS Electronics, Inc., 951 F. Supp. 923, 925 (S.D.N.Y. 1997)different case at this citeaa08dade4d30180a
F12fabricatedHarris v. Illinois Human Rights Commâ_x0080__x0099_n, 2022 IL App (1st) 210454unverifiable (closed database)76e7a93b15af03c5
F13fabricatedBerg v. Chevrolet Motor Div., 84 Wn.2d 102, 108, 524 P.2d 226 (1974)no such case38710030e2541b00
F14fabricatedUnited States v. Tittsworth, 630 F.3d 1029 (10th Cir. 2011)different case at this cite23f3863fd0fbc36b
F15fabricatedStevens v. Paulson, 254 Or App 111 (2012)different case at this cite0daa3c602ccf219d
F16fabricatedSnapper v. Redan, 523 U.S. 83 (1998)different case at this cite8bf75462d34ada2a
F17fabricatedDavis v. Davis, 590 N.E.2d 1372 (Ohio Ct. App. 1990)no such casecb15cbce964bad33
F18fabricatedKaplan v. Tuennerman, 87 Ohio App.3d 43, 621 N.E.2d 717 (8th Dist.1993)different case at this citeefe15f42770a318e
F19fabricatedBlack v. Black, 175 Ohio App.3d 113, 2008-Ohio-1525 (8th Dist.)different case at this cite5c00049409b11abc
F20fabricatedBrunswick Hills Twp. v. Bank of New York, 2007-Ohio-1480 (12th Dist.)different case at this cite9d7a7b437854fdcc
F21fabricatedMoran v. Moran, 2012-Ohio-1841, ¶ 13 (10th Dist. Ct. App.)different case at this cite94e685dd12453479
F22fabricatedJones Wolf Realty v 2 E. 79th St. Corpno citation in text81b31fc6b81ab430
F23fabricatedEllsworth v. Am. Arbitration Ass'n, 148 Ariz. 17, 19 (App. 1985)no such caseb7f8b3875ca75fce
F24fabricatedUnited States v. $17,900 in U.S. Currencyno citation in textc50f9ea7fdf926ea
F25fabricatedJarrod Johnson v. Water Light & Sinking Fund Commâ_x0080__x0099_nâ_x0080_¦, 74 F.4th 1308, 1313–17 (11th Cir. 2023)no such case85984eaf8c2c1b19
F26fabricatedAdams v. 3M Co., 67 F.4th 845, 853-55 (6th Cir. 2023)no such case506d8c8cae4338d0
F27fabricatedSterigenics U.S., LLC v. Sotera Health Co., 2020 WL 5645683 (N.D. Ill. Sep. 22, 2020)unverifiable (closed database)10313c36da428c9a
F28fabricatedKruger v. Kruger, 107 AD3d 1285, 1287 [3d Dept. 2013]different case at this cite79156ca5c9e24efa
F29fabricatedMissouri ex rel. Wilkerson v. Wilkerson, 817 S.W.2d 77 (Mo. Ct. App. 1991)different case at this cite22996e29c30dedc5
F30fabricatedRobinson v. Missouri Child Support Agency, 2021 WL 5437824 (Mo. Ct. App. 2021)unverifiable (closed database)8ab9beac0ae06327
F31fabricatedVerinata Health, Inc. v. Ariosa Diagnostics, Inc., 2014 WL 10321141, at *2 (N.D. Cal. Nov. 21, 2014)unverifiable (closed database)2d148c4754f74f6d
F32fabricatedKramer v. Trans-Lux Corp., 24 F.3d 1001 (7th Cir. 1994)no such case2be54fdc575d2cb1
F33fabricatedDOE V. SMITH, No. 3:22-cv-01987 (D. Conn. 2023)no citation in text2a6d0a96f1d3d913
F34fabricatedPeople v. Smith, 489 Mich. 292, 311 (2011)different case at this citecd89a3ed9e893fa3
F35fabricatedSavin v. City of Cleveland, 2022 WL 3715087 (6th Cir. 2022)unverifiable (closed database)3f3a30107c7133ad
F36fabricatedGN Netcom, Inc. v. Plantronics, Inc., No. 12-cv-1247, 2016 WL 3635771, at *4–5 (D. Del. June 29, 2016)unverifiable (closed database)c648d795d32a4b75
F37fabricatedBMS, Inc. v. United States, 12 Cl. Ct. 33 (1987)different case at this cite20f00194932542b3
F38fabricatedDoe v. Univ. of Mich., No. 18-11914, 2019 WL 11793988, at *8 (E.D. Mich., Aug. 6, 2019)unverifiable (closed database)eabbe4db030d3000
F39fabricatedStanley v. Univ. of Southern California (2022) 98 Cal.App.5th 151no such case20fb250dd4bee10b
F40fabricatedEustace v. Lynch (2012) 209 Cal.App.4th 1457exists — compare name by handb6e7c4d9777790ac
F41fabricatedCacchillo v. Commissioner, 130 T.C. 132 (2008)different case at this citea2b3a01560dc3e4a
F42fabricatedTefel v. Commissioner, 118 T.C. 324 (2002)different case at this cite222b09bdab09f789
F43fabricatedHimmelstein v. Comcast of the D.C., LLC, 908 F.3d 49; aff'g 44 F. Supp. 3d 1 (D.D.C. 2012)no such case4c6b94faee09401b
F44fabricatedLaPoint v. Family Orthodontics, P.A., 2020 WL 6118773 (D. Minn. Oct. 16, 2020)unverifiable (closed database)653fbd26d9d3f2ed
F45fabricatedHernandez v. Best Buy Co., 2012 WL 1970771 (D. Minn. May 31, 2012)unverifiable (closed database)740b7cfc4f09d541
F46fabricatedBush v. Lucas, 598 F. Supp. 3d 303, 316 (D. Md. 2022)no such case2d2429a13722f5ce
F47fabricatedMatter of Knapp v Knapp, 225 AD2d 1010 (4th Dept 1996)different case at this cite8038eee1a4a5026d
F48fabricatedMatter of Negron v St. Charles Hosp. & Rehab. Ctr., 121 AD3d 1427 (2d Dept 2014)different case at this citef2be5b91334bbc5c
F49fabricatedMatter of Polizzi v Polizzi, 226 AD2d 581 (2d Dept 1996)different case at this cite8899083b574524e7
F50fabricatedAlexander v. Lolavar, 127 Nev. 255 (2011)no such case759e114ebc51b73e
R01realElle Walton & Anor v R, [2026] EWCA Crim 1430verifiedac389321c30a3907
R02realCentral Bedfordshire Council v Bernard McDonaugh & Ors, [2026] EWHC 2860 (KB)exists — compare name by hande7a5c8a41237bee7
R03realTreal Care (UK) Limited, R (on the application of) v Secretary of State for the Home Department, [2026] EWCA Civ 1420verifiedc8b410ebb508d96a
R04realSmartestEnergy Business Limited v Odeon Arcade Limited, [2026] EWCA Civ 1412verified8e9f5d6e046a0d45
R05realA and C (Solicitors: Conflict of Interest), Re, [2026] EWHC 2842 (Fam)exists — compare name by hand3d55a0e114d48c49
R06real(D) (A Child with Complex Needs: Deprivation of Liberty), Re, [2026] EWHC 2846 (Fam)exists — compare name by hand4e58c56fc22ba670
R07realRM v The Secretary of State for the Home Department, [2026] EWCA Civ 1416verified1ad6cb75d00a2e89
R08realAAM v The Secretary of State for the Home Department, [2026] EWCA Civ 1411verified54041d6f3d9407b2
R09realHM Attorney General for England and Wales v BBC, [2026] EWHC 2802 (Admin)verified6767b4647d524285
R10realVerity Healthcare Limited v Cambridgeshire County Council, [2026] EWHC 2830 (TCC)verifiedca6ea31aff28cb07
R11realPayone/GmbH v Jerry Kofi Logo, [2026] EWHC 2834 (KB)verifiedc4bed277a4666a34
R12realUnited Living (South) Limited v Dovista UK Limited & Ors, [2026] EWHC 2676 (TCC)verified1f2b107145bd6e5f
R13realPPT v Independent Television News Limited & Anor, [2026] EWHC 2818 (KB)verifiedc168c009b4779bf3
R14realCaerphilly County Borough Council v Richard James Williamson, R (on the application of), [2026] EWCA Civ 1402verified3883ba89afd52191
R15realR v James Ibori, [2026] EWCA Crim 1396verifiedbf1808a7fd2d16ab
R16realLoughton Contracts Plc v The Amtico Company Limited, [2026] EWHC 2814 (TCC)verified4c545b4ada17c7d2
R17realVivid Housing Limited v Allianz Global Corporate & Specialty SE, [2026] EWCA Civ 1389verifiedcf447a5af7b6c138
R18realAlliance Petrochemical Investment (Singapore) PTE Ltd v Francesco Mazzagatti & Anor, [2026] EWCA Civ 1403exists — compare name by handae9db13049832925
R19realMarbury v. Madison, 5 U.S. (1 Cranch) 137 (1803)verified0fd7b239db6f00b7
R20realBrown v. Board of Education, 347 U.S. 483 (1954)verified007e339faf54e9f9
R21realMiranda v. Arizona, 384 U.S. 436 (1966)verifiedcfa7f6845d4429cb
R22realRoe v. Wade, 410 U.S. 113 (1973)verifiedef50765650397ab5
R23realUnited States v. Nixon, 418 U.S. 683 (1974)verified20c47d1bfec6e31b
R24realChevron U.S.A., Inc. v. NRDC, 467 U.S. 837 (1984)exists — compare name by handae1756f651b8e320
R25realDistrict of Columbia v. Heller, 554 U.S. 570 (2008)verified07f3a02019194104
R26realCitizens United v. FEC, 558 U.S. 310 (2010)exists — compare name by hand4af93e36de4a836f
R27realObergefell v. Hodges, 576 U.S. 644 (2015)verified3cf57ef7c052da30
R28realDobbs v. Jackson Women's Health Organization, 597 U.S. 215 (2022)verified4ebd74fb9ebe6abb
R29realStudents for Fair Admissions v. Harvard, 600 U.S. 181 (2023)verifiedd55b8a6b30361d77
R30real303 Creative LLC v. Elenis, 600 U.S. 570 (2023)verifiedeabfceecee3a1e93
R31realKennedy v. Bremerton School District, 597 U.S. 507 (2022)verified0ef711188b07873c
R32realNew York State Rifle & Pistol Assn. v. Bruen, 597 U.S. 1 (2022)verifiede3c503904ff5848a
R33realWest Virginia v. EPA, 597 U.S. 697 (2022)verified61f04e559a66ad2c
R34realBiden v. Nebraska, 600 U.S. 477 (2023)verifiede4343686f0976cab
R35realMoore v. Harper, 600 U.S. 1 (2023)verified765215e79902f9d2
R36realCounterman v. Colorado, 600 U.S. 66 (2023)verifieda5606e8067beb2b8
R37realGroff v. DeJoy, 600 U.S. 447 (2023)verified996a3d055258c4ed
R38realAndy Warhol Foundation v. Goldsmith, 598 U.S. 508 (2023)verified1deeec8fe2848226
R39realECLI:EU:C:2025:1014exists — compare name by hand8b8dd1e187a76cae
R40realECLI:EU:C:2025:975exists — compare name by hand97331fd159382306
R41realECLI:EU:C:2025:1017exists — compare name by hand3937abf2065f0a8e
R42realECLI:EU:C:2025:109exists — compare name by hand32f56f29b1b6252a
R43realECLI:EU:C:2025:617exists — compare name by handca6e075e0063a9cb
R44realECLI:EU:C:2025:230exists — compare name by hand3ccdc8b519a6fff1
R45realECLI:EU:C:2025:2exists — compare name by handd87d8a84ba9c8a42
R46realECLI:EU:C:2025:172exists — compare name by handb2dcb9671ad5d5b0
R47realECLI:EU:C:2025:283exists — compare name by hand423e1aa37846fc61
R48realECLI:EU:C:2025:645exists — compare name by handa44b9d67a0ea1d05
R49realThe Kingdom of Spain and another v The London Steam-Ship Ownersâ_x0080__x0099_ Mutual Insurance Association Limited No 2, [2026] UKSC 36exists — compare name by handaf7fc8a7f161dab9
R50realScottishPower (SCPL) Limited and others v Commissioners for His Majestyâ_x0080__x0099_s Revenue and Customs, [2026] UKSC 35exists — compare name by handb04ddd7309b3070d
M01real (matched)Donovan v. Commonwealth, 60 S.W.3d 581 (Ky. Ct. App. 2001)verified9a9ff2a5ea355cab
M02real (matched)State v. Bryan, 60 S.W.3d 713 (Mo. Ct. App. 2001)verifiedd5712d0587082837
M03real (matched)State v. Massey, 60 S.W.3d 625 (Mo. Ct. App. 2001)verified1df6a2b3af9f01ff
M04real (matched)In the Interest of L.E.W., 60 S.W.3d 47 (Mo. Ct. App. 2001)several cases share this citefe041c45eb2aac1c
M05real (matched)Ladzinski v. Meba Pension Trust, 951 F. Supp. 570 (D. Md. 1997)verifiedf1323d06db70a309
M06real (matched)Allstate Insurance v. Myers, 951 F. Supp. 1014 (M.D. Fla. 1996)verifiedeccbcfc019ee89e2
M07real (matched)Hernandez-Ebank v. Caplinger, 951 F. Supp. 99 (E.D. La. 1996)verified88d951baef73b93d
M08real (matched)Local 1575, International Longshoremen Ass'n v. Reich, 951 F. Supp. 329 (D.P.R. 1996)verified7bb7d01a3a559c7a
M09real (matched)United States v. Bellamy, 925 F.3d 1180 (10th Cir. 2019)verified16aa37ebb1f7b973
M10real (matched)United States v. Rodríguez-Reyes, 925 F.3d 558 (1st Cir. 2019)exists — compare name by hand0fb7162027ece7c0
M11real (matched)United States v. Brown, 925 F.3d 1150 (9th Cir. 2019)verified7a376897562f4bfc
M12real (matched)United States v. Robinson, 925 F.3d 997 (8th Cir. 2019)verified218711f30e648f76
M13real (matched)Curran v. Vincent, 175 Ohio App. 3d 146 (Ohio Ct. App. 2007)verifiedd4340aa50f330cf4
M14real (matched)Estate of Beavers v. Knapp, 175 Ohio App. 3d 758 (Ohio Ct. App. 2008)verifiedb2816339e9edae1a
M15real (matched)Zebrasky v. Valdes, 175 Ohio App. 3d 670 (Ohio Ct. App. 2008)verifieda3be76b83c99d48a
M16real (matched)State ex rel. Goff v. Industrial Commission, 175 Ohio App. 3d 60 (Ohio Ct. App. 2008)verified90adef1778069863
M17real (matched)State v. Jepson, 254 Or. App. 290 (Or. Ct. App. 2012)verified38cbd4cdab3d3b01
M18real (matched)State v. C. E. B., 254 Or. App. 353 (Or. Ct. App. 2012)exists — compare name by hand1d9e786e8f0c346b
M19real (matched)Oregon Occupational Safety & Health Division v. CBI Services, Inc., 254 Or. App. 466 (Or. Ct. App. 2013)verified96a8b7639b60ac05
M20real (matched)State v. Giles, 254 Or. App. 345 (Or. Ct. App. 2012)verified7f27451c1201b53e
M21real (matched)Grower's Pump, Inc. v. Industrial Commission, 148 Ariz. 430 (Ariz. Ct. App. 1985)verifiedb0125ea83490145e
M22real (matched)Gomez v. Industrial Commission, 148 Ariz. 575 (Ariz. Ct. App. 1985)verified84a4b2ddd384c854
M23real (matched)Schoenrock v. Cigna Health Plan of Arizona, Inc., 148 Ariz. 548 (Ariz. Ct. App. 1985)verifiedee716509fc740a87
M24real (matched)State v. Thurlow, 148 Ariz. 16 (Ariz. 1986)verified972adc1ef6bc6cc3
M25real (matched)People v. Breidenbach, 489 Mich. 1 (Mich. 2011)verifiedf6445fb4fe9ab05f
M26real (matched)Great Wolf Lodge of Traverse City, LLC v. Public Service Commission, 489 Mich. 27 (Mich. 2011)verified2e0d8762d0b7eea0
M27real (matched)Michigan Education Ass'n v. Secretary of State, 489 Mich. 194 (Mich. 2010)verified3eb30192687fdccd
M28real (matched)Lawrence M. Clarke, Inc. v. Richco Construction, Inc., 489 Mich. 265 (Mich. 2011)verified46548be533f4e093
M29real (matched)Glenbrook Capital Ltd. Partnership v. Dodds, 127 Nev. 196 (Nev. 2011)verified00e14ee8fb4bc665
M30real (matched)Rogers v. State, 127 Nev. 981 (Nev. 2011)verified0c7793f90e16f07d
M31real (matched)Rose v. State, 127 Nev. 494 (Nev. 2011)verifiedb031f994dd68823f
M32real (matched)State, Department of Taxation v. Masco Builder Cabinet Group, 127 Nev. 730 (Nev. 2011)verifiedbf8e47479aa16f2a
M33real (matched)American Safety Indemnity Co. v. Loganzo, 107 A.D.3d 835 (N.Y. App. Div. 2013)verified673d67647782c95c
M34real (matched)Nouveau Elevator Industries, Inc. v. Glendale Condominium Town & Tower Corp., 107 A.D.3d 965 (N.Y. App. Div. 2013)could not checka2ea8923a64111b7
M35real (matched)Borowski v. Ptak, 107 A.D.3d 1498 (N.Y. App. Div. 2013)verifiedbd9be5829b7f699d
M36real (matched)Le Cave LLC v. New York State Liquor Authority, 107 A.D.3d 447 (N.Y. App. Div. 2013)verified7f9d3ed6e477f163
M37real (matched)State v. Tarrytown Corporate Center II, 225 A.D.2d 82 (N.Y. App. Div. 1996)verified61f8bd627791f4df
M38real (matched)People v. Stevenson, 225 A.D.2d 323 (N.Y. App. Div. 1996)verified76f59afa6c7a325e
M39real (matched)People v. Farrington, 225 A.D.2d 633 (N.Y. App. Div. 1996)verified4fe6182119db1c1a
M40real (matched)Ferguson v. Belair Construction Corp., 225 A.D.2d 517 (N.Y. App. Div. 1996)verifiedb5582edb392012f8
M41real (matched)Capital One Financial Corp. & Subsidiaries v. Commissioner, 130 T.C. 147 (T.C. 2008)verified922e633a760074f1
M42real (matched)Nemitz v. Commissioner, 130 T.C. 102 (T.C. 2008)verifiedd472293e151e4d3e
M43real (matched)Barnes v. Commissioner, 130 T.C. 248 (T.C. 2008)verified2eb27935756ba381
M44real (matched)Perano v. Commissioner, 130 T.C. 93 (T.C. 2008)verified23a4773fe79fdb0d
M45real (matched)People v. Luna, 209 Cal. App. 4th 460 (Cal. Ct. App. 2012)verified325ce0c47022164d
M46real (matched)L.A. v. Superior Court, 209 Cal. App. 4th 976 (Cal. Ct. App. 2012)verifiedaf060445ff65a55a
M47real (matched)Don Johnson Productions, Inc. v. Rysher Entertainment, 209 Cal. App. 4th 919 (Cal. Ct. App. 2012)verified5e6227f60064d02f
M48real (matched)People v. Acevedo, 209 Cal. App. 4th 1040 (Cal. Ct. App. 2012)verified8c2ac5a59ab1250b
M49real (matched)Edmunds Holding Co. v. Autobytel Inc., 598 F. Supp. 2d 606 (D. Del. 2009)verified9de93d1d0e87dfab
M50real (matched)Rumber v. District of Columbia, 598 F. Supp. 2d 97 (D.D.C. 2009)verified7fd7cb56b2fe46bc

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