Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Principal curtailment with recast or term shortening: extra principal cap · case 01
An oversized prepayment drives the balance negative and the loan never reports a payoff payment.
Principal curtailment with recast or term shortening: extra principal cap · case 02
An oversized prepayment drives the balance negative and the loan never reports a payoff payment.
Principal curtailment with recast or term shortening: extra principal cap · case 03
An oversized prepayment drives the balance negative and the loan never reports a payoff payment.
Principal curtailment with recast or term shortening: extra principal cap · case 04
An oversized prepayment drives the balance negative and the loan never reports a payoff payment.
Principal curtailment with recast or term shortening: extra principal cap · case 05
An oversized prepayment drives the balance negative and the loan never reports a payoff payment.
Principal curtailment with recast or term shortening: recast remaining term · case 01
After a recast the payment drops as if the loan were brand new.
Principal curtailment with recast or term shortening: recast remaining term · case 02
After a recast the payment drops as if the loan were brand new.
Principal curtailment with recast or term shortening: recast remaining term · case 03
After a recast the payment drops as if the loan were brand new.
Principal curtailment with recast or term shortening: recast remaining term · case 04
After a recast the payment drops as if the loan were brand new.
Principal curtailment with recast or term shortening: recast remaining term · case 05
After a recast the payment drops as if the loan were brand new.
Principal curtailment with recast or term shortening: recast mode gate · case 01
Borrowers who chose term shortening see their payment reduced.
Principal curtailment with recast or term shortening: recast mode gate · case 02
Borrowers who chose term shortening see their payment reduced.
Principal curtailment with recast or term shortening: recast mode gate · case 03
Borrowers who chose term shortening see their payment reduced.
Principal curtailment with recast or term shortening: recast mode gate · case 04
Borrowers who chose term shortening see their payment reduced.
Principal curtailment with recast or term shortening: recast mode gate · case 05
Borrowers who chose term shortening see their payment reduced.
Principal curtailment with recast or term shortening: payoff month test · case 01
A loan whose balance plus interest equals the payment reports a zero final payment.
Principal curtailment with recast or term shortening: payoff month test · case 02
A loan whose balance plus interest equals the payment reports a zero final payment.
Principal curtailment with recast or term shortening: payoff month test · case 03
A loan whose balance plus interest equals the payment reports a zero final payment.
Principal curtailment with recast or term shortening: payoff month test · case 04
A loan whose balance plus interest equals the payment reports a zero final payment.
Principal curtailment with recast or term shortening: payoff month test · case 05
A loan whose balance plus interest equals the payment reports a zero final payment.
Principal curtailment with recast or term shortening: prepayment month key · case 01
Extra principal is applied one month after the borrower sent it.
Principal curtailment with recast or term shortening: prepayment month key · case 02
Extra principal is applied one month after the borrower sent it.
Principal curtailment with recast or term shortening: prepayment month key · case 03
Extra principal is applied one month after the borrower sent it.
Principal curtailment with recast or term shortening: prepayment month key · case 04
Extra principal is applied one month after the borrower sent it.
Principal curtailment with recast or term shortening: prepayment month key · case 05
Extra principal is applied one month after the borrower sent it.
Principal curtailment with recast or term shortening: payoff by curtailment · case 01
A loan paid off by an extra payment reports only the extra as the final payment.
Principal curtailment with recast or term shortening: payoff by curtailment · case 02
A loan paid off by an extra payment reports only the extra as the final payment.
Principal curtailment with recast or term shortening: payoff by curtailment · case 03
A loan paid off by an extra payment reports only the extra as the final payment.
Principal curtailment with recast or term shortening: payoff by curtailment · case 04
A loan paid off by an extra payment reports only the extra as the final payment.
Principal curtailment with recast or term shortening: payoff by curtailment · case 05
A loan paid off by an extra payment reports only the extra as the final payment.
Interest-only period with funding stub: amortization term · case 01
The amortizing payment is too small and a large final payment remains.
Interest-only period with funding stub: amortization term · case 02
The amortizing payment is too small and a large final payment remains.
Interest-only period with funding stub: amortization term · case 03
The amortizing payment is too small and a large final payment remains.
Interest-only period with funding stub: amortization term · case 04
The amortizing payment is too small and a large final payment remains.
Interest-only period with funding stub: amortization term · case 05
The amortizing payment is too small and a large final payment remains.
Interest-only period with funding stub: interest-only month count · case 01
The interest-only period bills one month too few.
Interest-only period with funding stub: interest-only month count · case 02
The interest-only period bills one month too few.
Interest-only period with funding stub: interest-only month count · case 03
The interest-only period bills one month too few.
Interest-only period with funding stub: interest-only month count · case 04
The interest-only period bills one month too few.
Interest-only period with funding stub: interest-only month count · case 05
The interest-only period bills one month too few.
Interest-only period with funding stub: stub day count · case 01
The first interest-only bill misses the funding day.
Interest-only period with funding stub: stub day count · case 02
The first interest-only bill misses the funding day.
Interest-only period with funding stub: stub day count · case 03
The first interest-only bill misses the funding day.
Interest-only period with funding stub: stub day count · case 04
The first interest-only bill misses the funding day.
Interest-only period with funding stub: stub day count · case 05
The first interest-only bill misses the funding day.
Interest-only period with funding stub: stub month selection · case 01
Every interest-only bill is prorated like the funding month.
Interest-only period with funding stub: stub month selection · case 02
Every interest-only bill is prorated like the funding month.
Interest-only period with funding stub: stub month selection · case 03
Every interest-only bill is prorated like the funding month.
Interest-only period with funding stub: stub month selection · case 04
Every interest-only bill is prorated like the funding month.
Interest-only period with funding stub: stub month selection · case 05
Every interest-only bill is prorated like the funding month.
Interest-only period with funding stub: total interest coverage · case 01
Lifetime interest disclosures omit the interest-only period.
Interest-only period with funding stub: total interest coverage · case 02
Lifetime interest disclosures omit the interest-only period.
Interest-only period with funding stub: total interest coverage · case 03
Lifetime interest disclosures omit the interest-only period.
Interest-only period with funding stub: total interest coverage · case 04
Lifetime interest disclosures omit the interest-only period.
Interest-only period with funding stub: total interest coverage · case 05
Lifetime interest disclosures omit the interest-only period.
Odd first period day count: due day 31 adjustment · case 01
Loans funded mid-month lose a day of interest when the first due date is the 31st.
Odd first period day count: due day 31 adjustment · case 02
Loans funded mid-month lose a day of interest when the first due date is the 31st.
Odd first period day count: due day 31 adjustment · case 03
Loans funded mid-month lose a day of interest when the first due date is the 31st.
Odd first period day count: due day 31 adjustment · case 04
Loans funded mid-month lose a day of interest when the first due date is the 31st.
Odd first period day count: due day 31 adjustment · case 05
Loans funded mid-month lose a day of interest when the first due date is the 31st.
Odd first period day count: actual basis · case 01
Actual/360 loans accrue interest on a 365-day year.
Odd first period day count: actual basis · case 02
Actual/360 loans accrue interest on a 365-day year.
Odd first period day count: actual basis · case 03
Actual/360 loans accrue interest on a 365-day year.
Odd first period day count: actual basis · case 04
Actual/360 loans accrue interest on a 365-day year.
Odd first period day count: actual basis · case 05
Actual/360 loans accrue interest on a 365-day year.
Odd first period day count: actual day inclusivity · case 01
Actual-day interest charges one extra day.
Odd first period day count: actual day inclusivity · case 02
Actual-day interest charges one extra day.
Odd first period day count: actual day inclusivity · case 03
Actual-day interest charges one extra day.
Odd first period day count: actual day inclusivity · case 04
Actual-day interest charges one extra day.
Odd first period day count: actual day inclusivity · case 05
Actual-day interest charges one extra day.
Odd first period day count: interest rounding stage · case 01
Stub interest drifts by several cents on long first periods.
Odd first period day count: interest rounding stage · case 02
Stub interest drifts by several cents on long first periods.
Odd first period day count: interest rounding stage · case 03
Stub interest drifts by several cents on long first periods.
Odd first period day count: interest rounding stage · case 04
Stub interest drifts by several cents on long first periods.
Odd first period day count: interest rounding stage · case 05
Stub interest drifts by several cents on long first periods.
Odd first period day count: non-positive period guard · case 01
A 30/360 first period that collapses to zero days returns zero interest instead of an error.
Odd first period day count: non-positive period guard · case 02
A 30/360 first period that collapses to zero days returns zero interest instead of an error.
Odd first period day count: non-positive period guard · case 03
A 30/360 first period that collapses to zero days returns zero interest instead of an error.
Odd first period day count: non-positive period guard · case 04
A 30/360 first period that collapses to zero days returns zero interest instead of an error.
Odd first period day count: non-positive period guard · case 05
A 30/360 first period that collapses to zero days returns zero interest instead of an error.
Payment application waterfall: suspense release · case 01
Funds held in suspense disappear once a qualifying payment arrives.
Payment application waterfall: suspense release · case 02
Funds held in suspense disappear once a qualifying payment arrives.
Payment application waterfall: suspense release · case 03
Funds held in suspense disappear once a qualifying payment arrives.
Payment application waterfall: suspense release · case 04
Funds held in suspense disappear once a qualifying payment arrives.
Payment application waterfall: suspense release · case 05
Funds held in suspense disappear once a qualifying payment arrives.
Payment application waterfall: threshold boundary · case 01
A payment exactly equal to the threshold is parked in suspense.
Payment application waterfall: threshold boundary · case 02
A payment exactly equal to the threshold is parked in suspense.
Payment application waterfall: threshold boundary · case 03
A payment exactly equal to the threshold is parked in suspense.
Payment application waterfall: threshold boundary · case 04
A payment exactly equal to the threshold is parked in suspense.
Payment application waterfall: threshold boundary · case 05
A payment exactly equal to the threshold is parked in suspense.
Payment application waterfall: waterfall order · case 01
Short payments reduce principal while interest remains unpaid.
Payment application waterfall: waterfall order · case 02
Short payments reduce principal while interest remains unpaid.
Payment application waterfall: waterfall order · case 03
Short payments reduce principal while interest remains unpaid.
Payment application waterfall: waterfall order · case 04
Short payments reduce principal while interest remains unpaid.
Payment application waterfall: waterfall order · case 05
Short payments reduce principal while interest remains unpaid.
Payment application waterfall: curtailment room · case 01
Overpayments near payoff drive the principal balance negative.
Payment application waterfall: curtailment room · case 02
Overpayments near payoff drive the principal balance negative.
Payment application waterfall: curtailment room · case 03
Overpayments near payoff drive the principal balance negative.
Payment application waterfall: curtailment room · case 04
Overpayments near payoff drive the principal balance negative.
Payment application waterfall: curtailment room · case 05
Overpayments near payoff drive the principal balance negative.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗