## TL;DR
Fix this in payroll preview anomaly agent by acting on the exact problem first: require every deduction amount in the anomaly report to match a deduction line on the employee pay preview or register entry, add a check that compares each reported amount against those source lines and removes any amount with no matching line, and rerun the anomaly check showing the source line beside each flagged deduction. Do not rerun the whole payroll workflow unchanged, because the same inputs produce the same failure. Prove the fix on one employee first, then rerun the full scope and reconcile the results against the payroll register.

```text
agent hallucinating deduction amounts not in source data for payroll preview anomaly check
```

## Use this when
- The operation in payroll preview anomaly agent fails with this exact problem: agent hallucinating deduction amounts not in source data for payroll preview anomaly check.
- The same failure repeats on retry with unchanged inputs.
- A payroll run, tax filing, garnishment check or pay close is blocked until this is resolved.

## Not for this skill when
- The notice is a platform outage from the vendor. Resolve that first, then return here if this problem remains.
- The payroll completes and you only disagree with a pay policy decision such as a rate or a benefit rule. That is a policy change, not this failure.

## Steps
1. Reproduce the failure on one named employee in payroll preview anomaly agent and record the full problem text plus the employee, pay period or filing involved. Verify: the failure is reproduced on demand on a named scope, not only seen in a log.
2. Apply the specific fix for this problem: require every deduction amount in the anomaly report to match a deduction line on the employee pay preview or register entry, add a check that compares each reported amount against those source lines and removes any amount with no matching line, and rerun the anomaly check showing the source line beside each flagged deduction. Verify: the single failing employee now behaves as the fix predicts, or the corrected value is visible on the record.
3. Check neighbouring employees, pay groups or filings that share the same pay code, deduction setup or import, because this class of failure rarely affects only one employee. Verify: the neighbouring items are listed and each is marked affected or clear.
4. Rerun the original operation in payroll preview anomaly agent on the previously failing scope, watching for the same problem rather than assuming success from a quiet log. Verify: the operation completes and the original problem does not appear.
5. Compare the result against the source of truth, the payroll register, the tax filings or the employee records, so a silent partial success is caught. Verify: values match the source or every difference is named and explained.
6. Record the fix, the triggering input and the verification result on the employee or run record so the next occurrence is recognised immediately. Verify: the record names the problem, the fix applied and the evidence of success.

## Variant phrasings

### agent hallucinating deduction amounts not in source data for payroll preview anomaly check
The verbatim form searchers paste from the console, report or run log. Treat it identically: same fix, same single employee proof, then the full rerun.

### How to fix - agent hallucinating deduction amounts not in source data for payroll preview anomaly check error hallucination failure
The how to phrasing for the same failure in payroll preview anomaly agent. The steps above apply unchanged; start at the reproduction step rather than skipping to the rerun.

### payroll preview anomaly agent troubleshooting for this failure
The symptom first phrasing used when the console hides the full problem. Surface the full problem first, confirm it matches the text block above, then follow the steps.

## Why it happens
When a preview returns an empty or partial deduction list, an agent can fill the gap with a plausible standard amount from a similar employee, and only an exact match against the employee own deduction lines separates a real anomaly from an invented one.

## Edge cases
- The employee was terminated, transferred or given a rate change after the failing run started. Refresh the employee state and reapply the fix against the current values, not the values from the failed run.
- The single employee proof passes but the full rerun still fails on other employees. Treat each remaining failure as its own scope, because a shared pay code or import can hide more than one cause.
- The source systems disagree on the correct value. The payroll register governs amounts paid, the tax filings govern amounts reported, and the employee record governs setup; record which source won and why.

Compatibility: payroll preview anomaly agent at current versions, plus the payroll system, time system or general ledger the query names; no extra tooling beyond access to the payroll register, tax filings and employee records needed to verify results.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_0naFuGIJ_gKv-es_hnX8RA