Compute gross-to-net pay, apply multi-jurisdiction withholding, and assemble the deposits, returns and pay statements each cycle needs, leaving the deposit, the filing and the release to the payroll officer who signs off.
Ingest hours, rates, elections and jurisdiction data from supported time, HR and payroll sources.
02
Normalise employee, location and pay-component data against the current pay calendar.
Reason
03
Compute gross-to-net pay, folding in the regular rate that 29 CFR Part 778 requires.
04
Withhold federal, state and local tax using the rule set configured for each jurisdiction.
05
Use each employee's current elections and the exemption threshold configured for the current period.
Decide
06
Flag deposit thresholds, jurisdiction changes and garnishment conflicts a run crosses.
07
Route every flagged run to a named payroll officer for release.
Out
08
Retain the calculation, the rule it ran against and the officer's release.
09
Execute write actions only inside the approval boundaries agreed during implementation.
→Product statement
The agent proposes the calculation; the payroll officer decides whether to deposit, file or release, and the employer remains the filer of record.
Example workflow
One pay run, input to release
AgentHuman
1Payroll inputs receivedTime system, HR change, benefit election or payroll API
2Context assembledHours, rates, elections, prior withholding and the jurisdiction rules on file
3Pay run computedGross-to-net figures, withholding, deposit schedule and confidence
4Controls appliedReciprocity checks, local-tax checks, garnishment-cap checks and confidence threshold
No human action required
Stages 1 to 4 run unaided, and nothing deposits or files at any of them — the agent is calculating, and the officer's lane opens at the confidence gate.
5DecisionBranches at the confidence threshold
High confidence
Goes to the payroll officer to release.
Low confidence
Adds a second calculation check first.
Officer approval
The run is held with its calculation, the rule it was run against and the confidence.
Approve · Correct · Escalate to controller
Approved — released for deposit▼
6Payroll system updatedOnly where write access and approval policy allow it
7Outcome evaluatedCalculation correctness, overrides, exceptions and deposit outcome
Corrections
Every officer correction is counted in the evaluation.
What should not run autonomously
Human approval stays in control
Outside the boundary — human approval required8 items
Depositing, filing or releasing any payroll run.
Reclassifying a worker's employment status.
Changing an employee's exemption status.
Setting a garnishment order's priority.
Automation boundaryAgent acts unaided
✓Compute gross-to-net pay and the withholding for each jurisdiction.
✓Apply the configured tax.
✓Assemble the deposit.
✓Flag what the officer should weigh, and hold the run for release.
Any deposit or filing happens inside the boundaries agreed at implementation, never ahead of release.
Manual off-cycle corrections with material impact.
Uncertain worker classification.
Disputed final-pay claims.
Changes to withholding rules or automation thresholds.
Example output
One pay run, annotated
Everything the agent computes is attached to the run it came from.
Payroll-calculation output · single runIllustrative example
Employee
Computed line
Net pay
Withholding basis
Confidence
Deposit status
Hourly, multi-state employee
Overtime recomputed with a non-discretionary shift differential folded into the regular rate
$1,286.40
Multi-state withholding rule set
96%
Released for deposit
As receivedTaken from the time system and the jurisdiction rules on file — nothing on this side is inferred.
Source facts usedReported hours and shift codePrior pay-period electionsWork-location record
Why this basisThe shift differential is non-discretionary and a person still decides.
ActionApproveCorrectEscalate to controller
What the score decidesBelow the configured threshold the run picks up a second calculation check before the officer.
Value
Where AI adds value
The same four claims, placed at the point in the workflow where each one applies.
Where the value landsValue 01 – 04
Every pay runFrom the payroll inputs on file
03Calculation
Compute from the record
Draw on the pay inputs on file and the withholding rules configured for each jurisdiction.
01Approved path
The liability does not transfer
Under 26 U.S.C. §6672, the trust-fund recovery penalty falls personally on the responsible person — never on the software.
02Human review
Focus the officer on exceptions
Threshold breaches, jurisdiction changes and garnishment conflicts are flagged, so the officer's read starts where liability concentrates.
04Build an evidence trail
The calculation, the rule it was run against and the officer who released the deposit stay on the run.
Integrations
Typical integrations
Five system groups connect to the same agent. Which of them are in scope is decided in discovery.
One blended correction rate can look acceptable while a small number of payroll cohorts absorb most of the rework. Nestack reports the correction rate by slice, not only in total.
Slice performance — reported separately, not only in aggregateIllustrative example
Slice
Failure rate
Lift
Lift vs. threshold
Status
Multi-state remote employees
7.1%
3.7×
Review
Non-discretionary bonus periods
5.3%
2.8×
Review
Hourly with shift differentials
3.4%
1.8×
Watch
Salaried, single jurisdiction
1.9%
0.7×
Normal
Bar: correction-rate lift vs. the single-jurisdiction salaried baseline · scale 0–4.0× · tick marks the 2.0× review threshold2 of 4 slices over threshold
Evidence-linked improvement
The loop does not close until the next run proves it
A cycle is done when the miscalculation has become a case the next release must pass. That suite is what the next payroll run is measured against.
Improvement cycle · five stagesSwitchback — the path turns at Improve and returns at Learn
01Detect
Correction rate rises in a payroll slice.
02Diagnose
The deposit that missed its window by a day is traced to the rule, the config or the workflow that let it happen.
03Improve
Version-stamp the change and attach the runs that exposed it.
04Verify
The affected cases run again, and a failure stops the release.
05Learn
It becomes a standing test, and the withholding rules change with it.
Learn → DetectThe return edge. The next deposit runs against a suite one case longer.
Typical build scope
Twelve workstreams across six weeks
The build scope read against the delivery timeline. Week structure follows the six-week plan — discovery, sources, payroll workflow, evaluation, integration, then production validation and handover.
WorkstreamWeek 1Week 2Week 3Week 4Week 5Week 6
01Payroll workflow discovery and boundary definition.
02Time, HR and tax source-system assessment.
03Jurisdiction and withholding-rule mapping and rule mapping.
04Payroll-input ingestion and normalisation.
05Gross-to-net logic and regular-rate.
06Confidence scoring and threshold routing.
07Payroll officer approval.
08Time, HR and payroll-system integration.
09Regular-rate regression cases.
10Guardrails and release controls.
11Run-trail instrumentation.
12Deployment, documentation and Agent Care handover.
12 workstreams · 6 weeks · bar shows the weeks a workstream is active — several run in parallelFinal scope and sequence confirmed in discovery
Engagement tiers
What each tier includes
Rows are the capabilities named in each tier's scope. Higher tiers include everything below them.
Capability✓ in scope · — not at this tierPilotOne pay cycle, one entityProductionProduction payroll systemsAdvancedMultiple entities / states
Introduced at Pilot
Gross-to-net calculation to your rules✓✓✓
Officer approval✓✓✓
Calculation-accuracy baseline✓✓✓
Introduced at Production
Reporting by jurisdiction—✓✓
Approval workflow in your systems—✓✓
Approved write-back—✓✓
Payroll-system integration—✓✓
Introduced at Advanced
Multi-state and local rules——✓
Multi-stage officer approvals——✓
High payroll volume——✓
Multi-state withholding controls——✓
Build priceFrom $5,000From $8,000Custom quote
Final build priceConfirmed after discovery based on integrations, workflow complexity, transaction volume, approval controls and deployment requirements.
Separate from buildBuild pricing is separate from recurring Agent Care, which covers managed monitoring, evaluations, incidents and verified improvements after launch.
What we need from you
What you bring, and what we build with it
Each input maps to a piece of build scope and a week in the delivery timeline.
You bringWe build with it
01Your payroll register and pay-component fields→Payroll-register ingestion and pay-component mappingWeek 1
02Representative historical pay runs→Pay-run ingestion and normalisation, and the calculation baselineWeek 2
03Your withholding tables and configured tax rules→Jurisdiction and withholding-rule mappingWeek 1
04Access to relevant APIs, feeds or exports→Time, HR and tax-system assessment, then integration setupWeek 2
05Payments you would not want deposited→Overtime cases and the evaluation suiteWeek 4
06What must reach a payroll officer→Confidence scoring, threshold routing, guardrails and approval controlsWeek 3
07Named payroll officers to review flagged runs→Officer approval workflow, then pilot and production validationWeeks 5–6
Nothing else is requiredDeployment, documentation and Agent Care handover are ours.
Delivery timeline
Four phases across six weeks
The phases are drawn on the weeks they occupy, so week 5 genuinely doubles rather than padding the plan.
PhaseW1W2W3W4W5W6
DiscoveryW1
BuildW2 – W3
EvaluateW4 – W5
Pilot & LaunchW5 – W6
Week focusW1Payroll workflow discovery, rule mapping and the automation boundaryW2Source integration and the calculation baselineW3Calculation workflow, confidence logic and approval controlsW4Evaluation suite, guardrails and failure-mode testingW5Payroll-system integration, pilot runs and targeted correctionsW6One pay cycle run under the payroll manager, then Agent Care handover
Reading the bandA bar covers only the weeks its work is named in. The week 5 overlap is real, not padding.
At the end of W6The final checks clear on a live run and monitoring moves to Agent Care.
DurationSix-week plan shown · typical delivery 4–6 weeks depending on scope confirmed in discovery.
Next step · Accounting AI agent
Build a payroll agent around your pay cycle.
Show us your payroll inputs, your withholding rules and who releases the deposit. We'll map the calculation workflow, set the automation boundary and name what stays with the payroll officer.
