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date_ambiguity

date_ambiguity-2026150000

Some dates are swapped to an ambiguous convention.

expects date_ambiguity

Statement files

3 highlighted lines differ from the same seed rendered without perturbations. That difference is the trap.

bnp_camt053.xmlUntouched by this perturbation
<?xml version='1.0' encoding='utf-8'?>
<Document xmlns="urn:iso:std:iso:20022:tech:xsd:camt.053.001.02">
<BkToCstmrStmt>
<GrpHdr>
<MsgId>LB-acct-2026150000-2-2025-04-30</MsgId>
<CreDtTm>2025-04-30T23:59:00+00:00</CreDtTm>
</GrpHdr>
<Stmt>
<Id>acct-2026150000-2</Id>
<ElctrncSeqNb>1</ElctrncSeqNb>
<CreDtTm>2025-04-30T23:59:00+00:00</CreDtTm>
<FrToDt>
<FrDtTm>2025-04-01T00:00:00+00:00</FrDtTm>
<ToDtTm>2025-04-30T23:59:59+00:00</ToDtTm>
</FrToDt>
<Acct>
<Id>
<IBAN>GB44LBEN31165281770453</IBAN>
</Id>
<Ccy>GBP</Ccy>
</Acct>
<Bal>
<Tp>
<CdOrPrtry>
<Cd>OPBD</Cd>
</CdOrPrtry>
</Tp>
<Amt Ccy="GBP">194421.74</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Dt>
<Dt>2025-04-01</Dt>
</Dt>
</Bal>
<Ntry>
<Amt Ccy="GBP">12987.10</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-01</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-01</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t011</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>TFR IRONBRIDGE TOOLING REF754593</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">4961.42</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-01</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-01</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t012</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>BP CASTLEGATE PROPERTY REF664323</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">286.95</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-02</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-02</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t019</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>DD HARBOURLIGHT IT REF427922</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">14929.55</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-05</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-05</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t024</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>SO IRONBRIDGE TOOLING REF999105</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">13142.20</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-07</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-07</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t007</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>DD KESTREL INSURANCE REF223769</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">2463.34</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-07</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-07</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t025</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>CR HARBOURLIGHT IT REF828220</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">9870.48</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-08</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-08</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t016</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>TFR HARBOURLIGHT IT REF116890</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">414.89</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-09</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-09</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t008</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>CR MOORLAND TELECOM REF956184</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">8348.36</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-10</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-10</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t010</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>FPI EASTFIELD ENERGY REF903305</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">12555.97</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-11</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-11</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t028</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>CR IRONBRIDGE TOOLING REF914935</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">223.05</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-12</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-12</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t003</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>FPI HARBOURLIGHT IT REF651350</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">872.33</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-12</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-12</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t022</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>BP NORTHGATE CLEANING REF787738</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">6410.25</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-16</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-16</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t002</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>FPO CASTLEGATE PROPERTY REF516203</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">1995.91</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-16</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-16</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t018</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>SO MOORLAND TELECOM REF530154</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">10314.89</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-17</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-17</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t009</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>SO EASTFIELD ENERGY REF696026</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">11404.68</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-18</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-18</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t020</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>CR GREENHOLM FOODS REF815652</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">1219.08</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-19</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-19</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t004</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>FPI DELPHINIUM MEDIA REF489746</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">11028.55</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-19</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-19</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t017</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>SO OSPREY LEASING REF141940</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">1270.52</Amt>
<CdtDbtInd>CRDT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-20</Dt>
</BookgDt>
<ValDt>
<Dt>2025-04-20</Dt>
</ValDt>
<AcctSvcrRef>acct-2026150000-2-t014</AcctSvcrRef>
<NtryDtls>
<TxDtls>
<RmtInf>
<Ustrd>CR BRAMBLE LOGISTICS REF328926</Ustrd>
</RmtInf>
</TxDtls>
</NtryDtls>
</Ntry>
<Ntry>
<Amt Ccy="GBP">14158.80</Amt>
<CdtDbtInd>DBIT</CdtDbtInd>
<Sts>BOOK</Sts>
<BookgDt>
<Dt>2025-04-20</Dt>
hsbc_statement.xlsxUntouched by this perturbation
[sheet: Statement]
HSBC Bank plc
Business Current Account Statement
Account name: LEDGERBENCH DEMO LTD
Sort code / Account number: 82-68-64 80284225
Account reference: acct-2026150000-1
Statement period: 01 Apr 2025 to 30 Apr 2025
Currency: GBP
Opening balance: 109955.04
Date Payment type Details Paid out Paid in
07 Apr 2025 BP FENWICK & PARTNERS REF447495 2991.59
07 Apr 2025 SO MOORLAND TELECOM REF705307 13927.83
08 Apr 2025 TFR NORTHGATE CLEANING REF960712 10580.40
09 Apr 2025 FPO OSPREY LEASING REF866120 10212.40
11 Apr 2025 FPI EASTFIELD ENERGY REF208880 8110.42
11 Apr 2025 CR CASTLEGATE PROPERTY REF307263 1104.91
12 Apr 2025 SO NORTHGATE CLEANING REF387827 9213.00
12 Apr 2025 TFR JUNIPER PAYROLL REF411170 4789.61
17 Apr 2025 SO AURORA CONSULTING LTD REF435799 10097.90
18 Apr 2025 SO AURORA CONSULTING LTD REF121861 8836.45
19 Apr 2025 BP DELPHINIUM MEDIA REF797471 14180.99
24 Apr 2025 BP JUNIPER PAYROLL REF918438 11284.89
24 Apr 2025 DD CASTLEGATE PROPERTY REF345121 2434.93
24 Apr 2025 TFR IRONBRIDGE TOOLING REF797754 3773.80
25 Apr 2025 FPI AURORA CONSULTING LTD REF756630 8024.54
26 Apr 2025 SO MOORLAND TELECOM REF824480 5465.75
28 Apr 2025 CR KESTREL INSURANCE REF598384 4123.41
29 Apr 2025 TFR BRAMBLE LOGISTICS REF987468 8713.07
29 Apr 2025 CR EASTFIELD ENERGY REF204009 12939.42
rbs_transactions.csv3 changed lines · first at line 6
"Date","Type","Description","Value","Account Name","Account Number","Ledger Ref"
"01/04/2025","BAL","OPENING BALANCE","142239.23","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"03/04/2025","FPO","FPO NORTHGATE CLEANING REF201395","-8491.16","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"04/04/2025","CR","CR GREENHOLM FOODS REF974990","11022.43","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"06/04/2025","TFR","TFR NORTHGATE CLEANING REF989292","8437.42","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"04/08/2025","FPI","FPI AURORA CONSULTING LTD REF949872","1829.89","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"10/04/2025","BP","BP LARKSPUR TRAVEL REF261999","-13609.04","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"04/10/2025","SO","SO MOORLAND TELECOM REF305915","-2815.88","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"04/12/2025","FPO","FPO MOORLAND TELECOM REF673489","-11342.07","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"13/04/2025","SO","SO CASTLEGATE PROPERTY REF287511","-2715.32","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"14/04/2025","DD","DD MOORLAND TELECOM REF855996","-12992.83","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"18/04/2025","FPO","FPO JUNIPER PAYROLL REF896819","-5877.11","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"21/04/2025","DD","DD CASTLEGATE PROPERTY REF341606","-10549.90","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"22/04/2025","DD","DD KESTREL INSURANCE REF541793","-3081.60","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"23/04/2025","BP","BP CASTLEGATE PROPERTY REF329935","-4677.18","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"23/04/2025","BP","BP EASTFIELD ENERGY REF296179","-10788.20","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"26/04/2025","BP","BP GREENHOLM FOODS REF402512","-8357.75","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"27/04/2025","BP","BP MOORLAND TELECOM REF533893","-2733.59","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"27/04/2025","DD","DD HARBOURLIGHT IT REF570796","-7481.27","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"29/04/2025","DD","DD AURORA CONSULTING LTD REF683892","-6607.69","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
"29/04/2025","BP","BP GREENHOLM FOODS REF767507","-13523.54","LEDGERBENCH DEMO LTD","16-53-58 97046721","acct-2026150000-3"
 

Ground truth

Public here because the benchmark is open; it is the model's prompt path that can never reach these values, not human readers.

AccountClosing balance
acct-2026150000-1£83,468.89
acct-2026150000-2£130,858.24
acct-2026150000-3£37,884.84

Recorded runs on this case

  • wrongSingle prompt2 steps · 11,024 tokens · Confidence medium

    Model claude-sonnet-4-6Measured 2026-08-20Bench v1.0Run 11eaa71b2d02Commit 3d38c30

  • exactAgent with tools20 steps · 44,057 tokens · Confidence high

    Model claude-sonnet-4-6Measured 2026-08-20Bench v1.0Run f140aa1e57f4Commit 384d72d

Step through any of these on the demo page.