We need answer JSON only. Need process payroll. Need follow rules. Need determine if conflict? Source documents: payroll record gross_pay 1117.86, month 2026-12, allowed_deduction 128.44. Contract gross_pay 1117.86. Optional contract_gross_pay present and differs? It equals, so no conflict. Need calculate using authoritative case reference schedule. Month 2026-12 => second-half row. Values replace defaults: rate 0.08, cap 4000.00, deduction cap 400.00, free 900.00, upper 3000.00, middle_rate 0.08, upper_rate 0.24.

Gross 1117.86. Employee contribution = rate * min(gross, cap) = 0.08 * 1117.86 = 89.4288. Round half-up to 2 decimals = 89.43. Check R2. Allowed deduction 128.44. Must not exceed selected deduction cap 400.00 or gross pay minus rounded employee contribution = 1117.86 - 89.43 = 1028.43. 128.44 <= both. Taxable pay = gross - employee contribution - allowed deduction = 1117.86 - 89.43 - 128.44 = 899.99? Let's compute: 1117.86 - 89.43 = 1028.43. -128.44 = 899.99. Yes.

Income tax progressive: taxable pay 899.99. Tax-free amount 900.00. Since taxable pay <= free, income tax = 0.00. Need round total = 0.00.

Net pay = gross - employee contribution - allowed deduction - income tax = 1117.86 - 89.43 - 128.44 - 0 = 899.99. Or taxable pay - income tax = 899.99. Return decision calculate, currency LCR, fields strings two decimals. Clauses: R1-R6? R9 not needed because no conflict. Need cite supporting calculation. "R1 through R6" maybe list? Allowed answer fields: calculate uses decision, currency, gross_pay, employee_contribution, allowed_deduction, taxable_pay, income_tax, net_pay, clauses. Need include clauses. Could cite ["R1","R2","R3","R4","R5","R6"]. No explanation necessary. Ensure JSON no markdown. Money strings two decimals.

Need be careful: R4 allowed deduction defaults. It says allowed_deduction is withheld. Good.

Potential issue: R7 conflict check: optional contract_gross_pay present and differs from gross_pay. Here equal, no conflict. Matching contract values require no amendment. Good.

Need maybe include clauses only relevant? User says "Use exactly required answer fields and only clauses that directly govern answer." We can include R1-R6? Directly govern calculation. R2 arithmetic, R3 contribution, R4 deduction, R5 tax, R6 net. R1 scope/reference. Yes.

Need final JSON only. Ensure no Markdown fences. Use strings. 

We need answer JSON only. Need compute. Need be careful. We have payroll record gross_pay 1117.86, month 2026-12, allowed_deduction 128.44. Contract gross_pay 1117.86 matches, no conflict. Authoritative schedule second-half applies for 2026-07 through 2026-12. Values:
rate 0.08, cap 4000.00, deduction cap 400.00, free 900.00, upper 3000.00, middle_rate 0.08, upper_rate 0.24.

Need calculate:
gross_pay = 1117.86.
employee_contribution = rate * min(gross, cap). min = 1117.86. 1117.86 * 0.08 = 89.4288. Round half-up to two decimals = 89.43 (since third decimal 8? Let's compute: 1117.86*8/100 = 8942.88/100? Wait 1117.86*0.08 = 89.4288. To two decimals: 89.43 because 89.4288 -> hundredths 2, thousandths 8 -> round up to 89.43). Yes.

allowed_deduction = 128.44. Need check <= deduction cap 400 and <= gross - employee_contribution = 1117.86 - 89.43 = 1028.43. 128.44 <= both. OK.

taxable_pay = gross - employee_contribution - allowed_deduction = 1117.86 - 89.43 - 128.44 = 899.99? Compute 1117.86 - 89.43 = 1028.43. 1028.43 - 128.44 = 899.99. Yes.

Income tax progressive:
Taxable pay 899.99. Free amount 900.00. Taxable pay <= free, so income tax = 0.00. Need round 0.00.

Net pay = gross - employee_contribution - allowed_deduction - income_tax = 1117.86 - 89.43 - 128.44 - 0.00 = 899.99. Wait net pay equals gross minus deductions and tax. Since taxable pay = gross - employee - allowed, and tax zero, net = 899.99. Yes.

Need output decision calculate, currency LCR, fields strings two decimals, clauses. Need include only clauses directly govern answer. R1 through R6? Calculated answers cite R1 through R6. Also R9 only when amendment needed. Here no amendment needed. But contract matches, no R9. Clauses likely ["R1","R2","R3","R4","R5","R6"]. Need maybe mention R1 selecting row, R2 arithmetic, R3 contribution, R4 deduction/taxable, R5 tax, R6 net. That's fine.

Need ensure JSON no markdown. Allowed fields include explanation optional. We can omit explanation. Need exact required fields. Use strings.

Double-check arithmetic and rounding:
Employee contribution: selected rate 0.08 * min(1117.86, 4000.00) = 89.4288 -> round half-up 89.43.
Taxable: 1117.86 - 89.43 - 128.44 = 899.99.
Tax: free 900.00, taxable 899.99, no tax.
Net: 1117.86 - 89.43 - 128.44 = 899.99.

Check R4 says subtract both employee contribution and allowed deduction from gross pay to obtain taxable pay. Employee contribution is rounded. Yes.

Potential subtlety: R2 "Do not round intermediate bracket products separately before summing income tax." Not relevant.

Potential issue: Contract gross_pay present and equals gross_pay. R7 says if optional contract_gross_pay present and differs from gross_pay, conflict. Here same, no conflict. Good.

Potential issue: Authoritative case schedule replaces defaults. We used second-half. Good.

Need output one JSON object. Ensure no markdown fences. Use decimal strings with two decimals.

Clauses: Should cite R1-R6. Maybe R9 not needed. The prompt says "Provide clause references supporting calculation." R6 says calculated answers cite R1 through R6. So include all. Is R2 maybe arithmetic. Yes.

Final JSON:
{
  "decision": "calculate",
  "currency": "LCR",
  "gross_pay": "1117.86",
  "employee_contribution": "89.43",
  "allowed_deduction": "128.44",
  "taxable_pay": "899.99",
  "income_tax": "0.00",
  "net_pay": "899.99",
  "clauses": ["R1","R2","R3","R4","R5","R6"]
}

Need ensure "calculate uses decision, currency, gross_pay, employee_contribution, allowed_deduction, taxable_pay, income_tax, net_pay, clauses" exactly. Good.

Let's final.

We need answer JSON only. Need process. Need follow rules. We have payroll record gross_pay 1117.86, payroll_month 2026-12, allowed_deduction 128.44. Contract gross_pay 1117.86 same. Authoritative schedule supplied. Need select second-half for 2026-12: rate 0.08, cap 4000.00, deduction cap 400.00, free 900.00, upper 3000.00, middle 0.08, upper 0.24.

Need calculate.

Gross = 1117.86. Employee contribution = rate * min(gross, wage cap) = 0.08 * 1117.86 = 89.4288. Round half-up to two decimals = 89.43 (since third decimal 8? 89.4288 -> 89.43). Check R3.

Allowed deduction = 128.44. Must not exceed selected deduction cap 400 or gross pay minus rounded employee contribution = 1117.86 - 89.43 = 1028.43. 128.44 <= both. OK.

Taxable pay = gross - employee contribution - allowed deduction = 1117.86 - 89.43 - 128.44 = let's compute. 1117.86 - 89.43 = 1028.43. 1028.43 - 128.44 = 899.99. Taxable = 899.99.

Income tax progressive: free 900.00. Taxable pay 899.99 <= free, so income tax = 0.00. Need round total = 0.00.

Net pay = gross - employee_contribution - allowed_deduction - income_tax = 1117.86 - 89.43 - 128.44 - 0 = 899.99? Wait net pay equals gross minus deductions. Since taxable pay is 899.99 and tax 0, net = 899.99. Yes.

Need return JSON object with fields decision, currency, gross_pay, employee_contribution, allowed_deduction, taxable_pay, income_tax, net_pay, clauses. Money strings two decimals. Clauses supporting calculation: R1 through R6? Since no amendment needed. Calculated answers cite R1 through R6. The prompt says "Provide clause references supporting calculation." R9 only when amendment needed. Here contract same, no amendment. So clauses ["R1","R2","R3","R4","R5","R6"] maybe. Need exactly required answer fields and only clauses that directly govern answer. The allowed answer fields include calculate uses decision, currency, gross_pay, employee_contribution, allowed_deduction, taxable_pay, income_tax, net_pay, clauses. Optional explanation permitted. We can include no explanation. Need JSON no markdown.

Check if any issue: contract_gross_pay present and equals gross_pay. R7.4 says if optional contract_gross_pay present and differs, conflict; matching contract values require no amendment. So no clarify. Good.

Need maybe cite R1 for selecting row and R3 for contribution, R4 for deduction/taxable, R5 for tax, R6 net. R2 arithmetic. "Calculated answers cite R1 through R6" so include all. Good.

Let's ensure money strings: gross_pay "1117.86"; employee_contribution "89.43"; allowed_deduction "128.44"; taxable_pay "899.99"; income_tax "0.00"; net_pay "899.99".

Double-check contribution: 1117.86 * 0.08 = 89.4288. Round half-up: 89.43. Yes.

Taxable: 1117.86 - 89.43 - 128.44 = 899.99. Tax-free amount 900.00. Taxable is 899.99, so no tax. Net = 1117.86 - 89.43 - 128.44 = 899.99. Yes.

Potential nuance: The authoritative schedule replaces defaults. We used second-half. Good.

Need final only JSON.