VerifyGate — evidence record

Repair report

spec: cart-total-tax-fix · mode: real · LLM adapter: nebius-token-factory

final verdict: PASS · repair rounds used: 1 / 3 · stopped: passed

LLM usage total: 2 call(s), 5318 total token(s)

Replay

python3 -m verifygate run --spec samples-js/spec.json --candidate samples-js/failing --mode real

spec hash: f9c36f2a2918c790004ce548874522d08990927bd12c4d1f0baa85d36539c1b7
candidate tree hash: b057a49e108268e29a5ce2f1e3984fdd9acff344cac55ca7ce1233d3ef79dfa7
record hash: 97c384f9d8fa1a89e0c9ecb1d7f0090a35ab26d0246247d6c5a7afdad06a0642
signature: d79aab3b61b4bee46564e12b3c7bc5c8…

Signed with the labelled public development key (demonstrates the mechanism; not production key management).

unit_tests FAIL

node --test

exit code: 1 · duration: 550 ms · timed out: False

✔ subtotal sums price * qty (1.091076ms)
✖ total applies the tax rate (1.421111ms)
✖ total rounds to cents (0.284286ms)
✔ total with zero tax equals the subtotal (0.301252ms)
ℹ tests 4
ℹ suites 0
ℹ pass 2
ℹ fail 2
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 195.377733

✖ failing tests:

test at cart.test.js:18:1
✖ total applies the tax rate (1.421111ms)
  AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
  
  25.5 !== 30.6
  
      at TestContext.<anonymous> (/tmp/verifygate-fii_adr6/cart.test.js:19:10)
      at Test.runInAsyncScope (node:async_hooks:227:14)
      at Test.run (node:internal/test_runner/test:1397:25)
      at Test.processPendingSubtests (node:internal/test_runner/test:969:18)
      at Test.postRun (node:internal/test_runner/test:1537:19)
      at Test.run (node:internal/test_runner/test:1462:12)
      at async startSubtestAfterBootstrap (node:internal/test_runner/harness:387:3) {
    generatedMessage: true,
    code: 'ERR_ASSERTION',
    actual: 25.5,
    expected: 30.6,
    operator: 'strictEqual',
    diff: 'simple'
  }

test at cart.test.js:22:1
✖ total rounds to cents (0.284286ms)
  AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
  
  29.97 !== 32.07
  
      at TestContext.<anonymous> (/tmp/verifygate-fii_adr6/cart.test.js:23:10)
      at Test.runInAsyncScope (node:async_hooks:227:14)
      at Test.run (node:internal/test_runner/test:1397:25)
      at Test.processPendingSubtests (node:internal/test_runner/test:969:18)
      at Test.postRun (node:internal/test_runner/test:1537:19)
      at Test.run (node:internal/test_runner/test:1462:12)
      at async Test.processPendingSubtests (node:internal/test_runner/test:969:7) {
    generatedMessage: true,
    code: 'ERR_ASSERTION',
    actual: 29.97,
    expected: 32.07,
    operator: 'strictEqual',
    diff: 'simple'
  }

entry hash: 04e8bda1f1fe8d24…

repro_script FAIL

node repro.js

exit code: 1 · duration: 66 ms · timed out: False

node:assert:152
  throw new AssertionError(obj);
  ^

AssertionError [ERR_ASSERTION]: cart repro failed: got 20

20 !== 24

    at Object.<anonymous> (/tmp/verifygate-fii_adr6/repro.js:7:8)
    at Module._compile (node:internal/modules/cjs/loader:1929:14)
    at Object..js (node:internal/modules/cjs/loader:2060:10)
    at Module.load (node:internal/modules/cjs/loader:1651:32)
    at Module._load (node:internal/modules/cjs/loader:1443:12)
    at wrapModuleLoad (node:internal/modules/cjs/loader:261:19)
    at Module.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:154:5)
    at node:internal/main/run_main_module:33:47 {
  generatedMessage: false,
  code: 'ERR_ASSERTION',
  actual: 20,
  expected: 24,
  operator: 'strictEqual',
  diff: 'simple'
}

Node.js v24.20.0

entry hash: f6447476e835188d…

Diagnosis commentary — never a verdict input

**Diagnosis**

| Check | What failed | Observed vs. Expected |
|-------|-------------|-----------------------|
| `unit_tests` – *total applies the tax rate* | `total` returned **25.5** instead of **30.6** | Tax amount appears to be missing or under‑applied. |
| `unit_tests` – *total rounds to cents* | `total` returned **29.97** instead of **32.07** | Same underlying tax error, plus the value is being truncated rather than rounded to the nearest cent. |
| `repro_script` | `cart repro failed: got 20` vs. expected **24** | The same calculation used in the unit tests is off by a constant amount (≈ 20 % low). |

**Most likely cause**  
The function that computes the cart total (likely in `cart.js` or a similar module) is either:

1. **Not applying the tax rate** – it returns only the subtotal (`price * qty`).  
2. **Using integer arithmetic** – causing the tax fraction to be dropped before rounding.  
3. **Truncating instead of rounding** – e.g., using `Math.floor` or casting to `int` before converting to cents.

Both test failures show the same pattern: the result is lower than expected by roughly the tax amount, and the cents‑rounding test fails because the value is not properly rounded.

**Smallest next fix to try**

1. Locate the total‑calculation code (search for `total`, `tax`, or the test lines in `cart.test.js`).  
2. Ensure the tax is applied **after** computing the subtotal:

```javascript
// Example buggy code
// const total = price * qty;   // <-- missing tax

// Fixed version
const subtotal = price * qty;
const totalWithTax = subtotal * (1 + TAX_RATE); // TAX_RATE as a decimal, e.g., 0.20
const total = Math.round(totalWithTax * 100) / 100; // round to nearest cent
```

3. Run the checks again:

```bash
node --test        # unit_tests
node repro.js      # repro_script
```

If the tests pass, the issue was the missing tax application/incorrect rounding. If they still fail, inspect the exact values of `price`, `qty`, and `TAX_RATE` used in the test to confirm the expected numbers.

LLM adapter: nebius-token-factory · reference source: tavily

References unavailable: TAVILY_API_KEY is not set; references skipped (diagnosis proceeds without them) The verdict above does not depend on references.

LLM usage sealed in the hash chain

Total tokens: 2085

Patch from previous attempt applied to: cart.js

Replay

python3 -m verifygate replay --record <repair-report.json> --spec samples-js/spec.json --candidate samples-js/failing --mode real # attempt 1: patched copy, reconstructed from the report's recorded patch

spec hash: f9c36f2a2918c790004ce548874522d08990927bd12c4d1f0baa85d36539c1b7
candidate tree hash: 1648bb05cc9a96bb76e9690c82f6613c6f399f2304e3ff6bbb0426e59694f728
record hash: 140dd987bb7a74630d520fee3e68ff077afd248dfd839063276119e17e555d3f
signature: e4dfa559c737484a38778ad2eaaa3344…

Signed with the labelled public development key (demonstrates the mechanism; not production key management).

unit_tests PASS

node --test

exit code: 0 · duration: 704 ms · timed out: False

✔ subtotal sums price * qty (4.351124ms)
✔ total applies the tax rate (0.558187ms)
✔ total rounds to cents (0.282494ms)
✔ total with zero tax equals the subtotal (0.168542ms)
ℹ tests 4
ℹ suites 0
ℹ pass 4
ℹ fail 0
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 403.713496

entry hash: 6e85bd95d4c5efaf…

repro_script PASS

node repro.js

exit code: 0 · duration: 129 ms · timed out: False

repro OK: 24

entry hash: b2a9618b64da1286…

LLM usage sealed in the hash chain

Total tokens: 3233