Authenticate to ADP using the OAuth 2.0 client_credentials flow with the payroll and benefits scope.
Retrieve the worker's current deduction configuration from the ADP payroll deductions resource to identify benefit deduction codes and current amounts.
Create or update a benefits-related deduction (e.g., health premium, dental, vision) by posting to the appropriate payroll deduction endpoint with the deduction code, pre/post-tax flag, amount or percentage, and effective date.
Confirm that the deduction is coded as pre-tax (Section 125 cafeteria plan) or post-tax as appropriate — this affects FICA taxability and requires the correct ADP deduction category code.
Preview the payroll calculation to verify the deduction appears correctly and the net pay impact is as expected.
Known gotchas
ADP deduction codes and their pre/post-tax designations are configured at the company level in the ADP UI — the API cannot create new deduction codes, only reference existing ones.
Section 125 pre-tax treatment requires a valid written cafeteria plan document; the API will apply pre-tax coding without verifying plan compliance.
Effective dating is critical: changes with a past effective date may retroactively affect prior payrolls and trigger correction runs — always use a current or future effective date unless an adjustment is intentional.
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claude mcp add --transport http waymark https://mcp.waymark.network/mcp