Let me start by listing the documents to get the case inputs.

There are three documents: payroll, contract, amendment. Let me read all three in parallel since they're independent.

Payroll record: gross_pay = 3807.00, payroll_month = 2026-04, allowed_deduction = 181.70.

Contract: gross_pay = 3807.01 — differs from payroll gross_pay (3807.00). So there's a conflict per R7.4.

Amendment: gross_pay = 3807.00, approved = true, effective_month = 2026-06. Payroll month is 2026-04. The amendment's effective month (2026-06) is later than the payroll month (2026-04), so it does NOT resolve the conflict. Per R9: "It resolves a contract conflict only if it is approved, its effective month is no later than the payroll month, and its amount equals the payroll record's gross pay."

Here: approved = true ✓, amount equals payroll gross pay (3807.00 = 3807.00) ✓, but effective_month 2026-06 > payroll month 2026-04 ✗. So the amendment is future — it does not resolve the conflict.

Therefore, per R7.4: return decision "clarify", reason_code "CONFLICTING_GROSS_PAY", citing R7 and R9.

Wait — but before that, I should check the order of checks in R7:
1. Missing gross_pay — present, so no.
2. Missing payroll_month — present, so no.
3. Month without a reference row — 2026-04 is in 2026, which is covered. But should I check lookup_reference? The conflict check is #4. The month 2026-04 is covered by 2026 rows, so there is a reference row. I could verify with lookup_reference, but since the conflict resolves to clarify, I don't need to compute. However, to be thorough, the order of checks: check #3 (month without reference row) comes before #4 (conflicting gross pay). 2026-04 is covered by the reference table (only 2026 is covered). So check #3 passes, and check #4 triggers.

Actually, should I call lookup_reference to confirm 2026-04 has a row? The rules say "Only 2026 is covered." 2026-04 is within 2026, so a reference row exists. The clarification is due to the conflicting gross pay, not the month. I don't strictly need the reference row for a clarify answer. But being careful: the check order matters. Since the month is in 2026, there is a reference row (first-half covers Jan–Jun presumably). I could call lookup_reference("first-half") to confirm, but it's not needed for the clarify output. Actually, let me think about whether the conflict check might be resolved differently.

R9: amendment resolves conflict only if approved AND effective_month ≤ payroll_month AND amount equals payroll gross pay. Here effective_month 2026-06 > 2026-04. So it's a future amendment — does not resolve. Per R7.4: "If optional contract_gross_pay is present and differs from gross_pay, neither source takes precedence unless an approved amendment resolves it under R9. Otherwise return decision: clarify and reason_code: CONFLICTING_GROSS_PAY, citing R7 and R9."

So the answer: clarify, CONFLICTING_GROSS_PAY, clauses R7 and R9.

The clarification should include a short explanation naming the unresolved blocker and asking for its resolution.

Fields for clarify: decision, reason_code, clauses. Optional explanation string. Do not include calculated monetary fields.

Let me also double check: the amendment amount equals the payroll record's gross pay (3807.00). Yes. But effective month is 2026-06, which is after payroll month 2026-04. So it fails the effective-month condition. "A draft, future, or different-amount amendment does not resolve a conflict." This is a future amendment.

So the answer:

{
  "decision": "clarify",
  "reason_code": "CONFLICTING_GROSS_PAY",
  "clauses": ["R7", "R9"],
  "explanation": "..."
}

Should I call lookup_reference to verify the month is covered? The check order in R7 puts month-without-reference-row (check 3) before conflict (check 4). Since 2026-04 is in 2026 and "Only 2026 is covered," there is a reference row. I'm confident. But to be safe and demonstrate diligence, I could call lookup_reference("first-half") — 2026-04 is in the first half. It's not strictly necessary for the clarify decision, and the instructions say to use lookup_reference for reference rows. Since I'm not calculating, I don't need it. However, confirming check #3 passes before check #4 seems prudent. Let me call lookup_reference("first-half") to confirm 2026-04 has a row. That's a cheap verification.

Actually, the instruction says "Reference rows are available only through lookup_reference." Since my decision doesn't depend on the reference values, I could skip. But the check order requires confirming a reference row exists for the month before reaching check 4. Let me do it to be rigorous.

2026-04 falls within 2026-01 through 2026-06 (first half), so a reference row exists — check #3 passes.

Now check #4: contract_gross_pay (3807.01) differs from gross_pay (3807.00). The amendment is approved and its amount (3807.00) equals the payroll gross pay, but its effective_month (2026-06) is later than the payroll month (2026-04). Under R9, a future amendment does not resolve the conflict. Therefore, per R7.4, return clarify with CONFLICTING_GROSS_PAY, citing R7 and R9.

Output JSON without Markdown fences, no surrounding prose. Wait — the system prompt says "Return one JSON object without Markdown fences or surrounding prose." So my final answer must be just the JSON object.

Fields: decision, reason_code, clauses, plus optional explanation. No monetary fields.

Let me start by listing the documents to see what case inputs exist.

There are three documents: payroll, contract, and amendment. Let me read all three. They're independent reads, so I can do them in parallel.

Let me analyze:

- Payroll record: gross_pay = 3807.00, payroll_month = 2026-04, allowed_deduction = 181.70
- Contract: gross_pay = 3807.01
- Amendment: gross_pay = 3807.00, approved = true, effective_month = 2026-06

R7 check order:
1. Missing gross_pay? No, it's present (3807.00).
2. Missing payroll_month? No, present (2026-04).
3. Month without reference row? 2026-04 is in 2026, which is covered. Need to check the reference row via lookup_reference.
4. Conflicting gross_pay? contract_gross_pay = 3807.01 differs from gross_pay = 3807.00. An amendment is present: approved = true, but effective_month = 2026-06, which is AFTER the payroll month 2026-04. R9: amendment resolves conflict only if approved, effective month no later than payroll month, and amount equals payroll record's gross pay. Here effective month 2026-06 > 2026-04, so it does NOT resolve the conflict. Therefore decision: clarify, reason_code: CONFLICTING_GROSS_PAY, citing R7 and R9.

Wait — but should I check the reference row first? The order in R7 is 1-4. Step 3 says a month without a reference row → NO_APPLICABLE_REFERENCE. 2026-04 is covered (only 2026 is covered). But I should verify via lookup_reference that 2026-04 has a row. Actually, the check order matters: step 4 comes after step 3. Since 2026-04 is within 2026, there should be a reference row. Let me verify with lookup_reference anyway to be thorough — actually, the conflict resolution at step 4 doesn't depend on the reference row. But to be safe, I should confirm the month has a reference row before returning CONFLICTING_GROSS_PAY, because if the month had no row, step 3 would take precedence.

Let me look up the reference for 2026-04. April is in the first half (first-half vs second-half — presumably first half = Jan-Jun, second half = Jul-Dec). Let me call lookup_reference with "first-half".

Actually, do I need to? The conflict check is step 4 and the month check is step 3. Since 2026-04 is in 2026, it's covered. But to be rigorous, I should confirm the row exists. Let me call lookup_reference first-half to confirm 2026-04 has a row.

Hmm, but the answer is clarify regardless — I don't need monetary fields. But the citation for CONFLICTING_GROSS_PAY is R7 and R9. If the month lacked a row, it'd be NO_APPLICABLE_REFERENCE (R1, R7). Since 2026-04 is in 2026 and only 2026 is covered, the row exists. Still, verifying is cheap and safe. Let me do the lookup to confirm.

Also note: the amendment's amount (3807.00) equals the payroll record's gross pay (3807.00), and it's approved, but its effective month (2026-06) is later than the payroll month (2026-04). So it fails the "effective month no later than payroll month" condition. Therefore it does not resolve the conflict → CONFLICTING_GROSS_PAY.

Let me verify the reference row exists for 2026-04 with lookup_reference first-half.

The first-half reference covers 2026-01 through 2026-06, so 2026-04 has a reference row. Step 3 passes.

Step 4: contract_gross_pay = 3807.01 differs from gross_pay = 3807.00. The amendment is approved and its amount equals the payroll gross pay (3807.00), but its effective_month is 2026-06, which is later than the payroll month 2026-04. Per R9, the amendment resolves the conflict only if approved AND effective month ≤ payroll month AND amount equals payroll gross pay. The effective month condition fails, so the conflict is unresolved.

Therefore: decision "clarify", reason_code "CONFLICTING_GROSS_PAY", citing R7 and R9. No monetary fields. Include a short explanation naming the unresolved blocker and asking for its resolution.

Per the rules: "For clarification include a short explanation naming the unresolved blocker and asking for its resolution." Also "Missing required values include explicit null" — but that applies to missing gross_pay/payroll_month cases. Here the required values are present; the issue is a conflict. I shouldn't include monetary fields.

Allowed answer fields for clarify: decision, reason_code, clauses, plus optional explanation. So:

{
  "decision": "clarify",
  "reason_code": "CONFLICTING_GROSS_PAY",
  "clauses": ["R7", "R9"],
  "explanation": "..."
}

The explanation: The payroll record's gross pay (3807.00 LCR) conflicts with the contract gross pay (3807.01 LCR). The amendment is approved and matches the payroll amount, but its effective month (2026-06) is later than the payroll month (2026-04), so under R9 it cannot resolve the conflict. An approved amendment effective no later than 2026-04 with amount 3807.00 is needed to resolve it.

I should not include monetary fields for clarify. Should I mention amounts in the explanation? That's fine as prose.

Return one JSON object without Markdown fences.

Let me start by listing the documents to get the case inputs.

There's a payroll record, a contract, and an amendment. Let me read all three.

Let me analyze:

- Payroll record: gross_pay = 3807.00, payroll_month = 2026-04, allowed_deduction = 181.70
- Contract: gross_pay = 3807.01 (conflicts with payroll gross_pay 3807.00)
- Amendment: gross_pay = 3807.00, approved = true, effective_month = 2026-06

Per R9: An amendment resolves a contract conflict only if:
1. Approved: yes (true)
2. Effective month no later than payroll month: 2026-06 vs payroll month 2026-04. 2026-06 is AFTER 2026-04. So the amendment is future relative to the payroll month. It does NOT resolve the conflict.
3. Amount equals payroll record's gross pay: 3807.00 = 3807.00 (yes)

Since the amendment's effective month (2026-06) is later than the payroll month (2026-04), it does not resolve the conflict. Per R7 item 4: If optional contract_gross_pay is present and differs from gross_pay, neither source takes precedence unless an approved amendment resolves it under R9. Otherwise return decision: "clarify" with reason_code: "CONFLICTING_GROSS_PAY", citing R7 and R9.

So the answer is clarify with CONFLICTING_GROSS_PAY.

Wait — but should I check the reference row first? The order in R7:
1. Missing gross_pay — no, present.
2. Missing payroll_month — no, present.
3. Month without a reference row — 2026-04 is covered (only 2026 covered). Let me verify via lookup_reference. Actually, the check order says month without a reference row comes before the contract conflict check. 2026-04 should have a row. But do I need to look it up? The conflict check happens regardless. Actually, since the conflict is unresolved, we return clarify before calculating. But the order matters: check 3 (NO_APPLICABLE_REFERENCE) comes before check 4 (CONFLICTING_GROSS_PAY). Since 2026-04 is in 2026, it has a reference row, so we proceed to check 4, which fails → clarify CONFLICTING_GROSS_PAY.

I don't strictly need lookup_reference for the clarify answer, but to be thorough in confirming 2026-04 has a row, I could look it up. The instructions say reference rows are available only through lookup_reference. For a clarify answer, I don't need the rates. But checking that the month is covered matters for the ordering. R1 says only 2026 is covered, and 2026-04 is in 2026. I could do a lookup to confirm the row exists. Let me do the second-half lookup since 2026-04 is in the second half? Wait — first-half vs second-half. 2026-04 — April. Is April first half or second half of the year? First half would be Jan–Jun, second half Jul–Dec. Hmm, but the lookup_reference enum is "first-half" and "second-half" — this likely refers to halves of the year. April is in the first half (Jan–Jun). Let me look up first-half to confirm the row for 2026-04 exists.

Actually, for the clarify answer, I don't need the numbers. But confirming the row exists ensures the correct ordering of clarification reasons. Let me do it to be safe.

The amendment: approved=true, amount matches payroll gross (3807.00), but effective_month 2026-06 > payroll month 2026-04. So it's a "future" amendment relative to the payroll month and does not resolve the conflict. Per R9: "A draft, future, or different-amount amendment does not resolve a conflict."

So decision: clarify, reason_code: CONFLICTING_GROSS_PAY, clauses: R7, R9.

Should I include an explanation? Yes, optional explanation string is permitted. For clarification include a short explanation naming the unresolved blocker and asking for its resolution.

Fields for clarify: decision, reason_code, clauses. Optional explanation.

Let me do the lookup_reference first-half to confirm 2026-04 is covered (so the conflict check is the operative blocker).

The first-half lookup shows months ["2026-01", "2026-06"]. Hmm, 2026-04 is not in that list. Let me check the second-half too. Wait — "first-half" and "second-half" might refer to halves of the month? Or the year? The months listed are "2026-01" and "2026-06" — that's odd. Maybe first-half covers months 2026-01 through 2026-06 (Jan–Jun), and the listed months are just endpoints? Or maybe the schedule has two rows: one covering 2026-01 to 2026-05 and another 2026-06 to 2026-12? Let me check second-half.

So:
- First-half: months 2026-01 through 2026-06 (the list shows ["2026-01", "2026-06"], likely the range endpoints).
- Second-half: months 2026-07 through 2026-12.

Payroll month 2026-04 falls in the first-half range (2026-01 to 2026-06). So there IS a reference row for 2026-04. Good — check 3 passes.

Now check 4: contract_gross_pay = 3807.01 differs from payroll gross_pay = 3807.00. The amendment is approved and its amount (3807.00) equals the payroll record's gross pay, but its effective_month is 2026-06, which is later than the payroll month 2026-04. Per R9, an amendment resolves a conflict only if approved, effective month ≤ payroll month, and amount equals payroll gross. Here the effective month (2026-06) is after the payroll month (2026-04), so it's a "future" amendment and does not resolve the conflict.

Therefore: decision = "clarify", reason_code = "CONFLICTING_GROSS_PAY", clauses = ["R7", "R9"].

No monetary fields should be returned. Include a short explanation naming the unresolved blocker and asking for its resolution.

The amendment is otherwise qualifying (approved: true, amount matches 3807.00), but it takes effect 2026-06, two months after the April payroll month, so it cannot resolve the contract-vs-payroll conflict for April.

Output JSON without markdown fences, no surrounding prose. Fields: decision, reason_code, clauses, explanation.