## 1. Agree period and date basis

Read source-invoices.json and filing-rules.md only. Restate period, date basis, inclusion, deduplication and missing-value rules. Index all 8 ids/sources. Do not read real email, connect Sheets, pay or upload material.

Expected: Eight source records with clear boundaries.
Check: IN07 is excluded by October invoice date, not email timing.

## 2. Extract fields without repairing unknown values

Extract source_id, vendor, invoice number, date, amount string, currency, paid/void state, source and gaps for 8 extracts. Keep unknowns null. Infer no FX, tax or illegible digit. Save extracted.json before reading answers.

Expected: Structured source-preserving records.
Check: IN05 amount remains null; IN04/IN06 do not become valid paid receipts.

## 3. Find duplicates and retain every original

Identify duplicate candidates with primary record, duplicate sources, matching fields and evidence. Link IN02 to IN01 while retaining both. Flag same-key amount/date conflicts. Delete no attachments or originals. Save dedupe.csv.

Expected: A duplicate relation excluding IN02 from totals.
Check: All 8 originals remain; retained-file and unique-total counts differ.

## 4. Reconcile by currency and account for exceptions

Total eligible unique records by currency using minor units. Return ids, count, total per currency and separate unpaid, review, void, outside-period, duplicate queues. No FX or mixed-currency total; unknown is not 0. Account for all 8 inputs.

Expected: CNY 150.00, USD 20.00; 3 paid and 5 other outcomes.
Check: No combined 170; all queues reconcile to 8 inputs.

## 5. Review CSV before deciding on an append

Produce a local register CSV with formula-triggering text escaped and original values traceable. Only after later approval of a specific sheet/range, check keys, append confirmed new records in raw-value mode, record range and read back. Without tools return CSV; no Drive upload, history edits or payments.

Expected: A local register; actual append evidence only if later authorized.
Check: Reruns do not duplicate invoices; a file is not claimed as an online write.

## 6. Keep review queues and handle late arrivals

Draft an invoice-register Skill with month boundaries, fields, deduplication, currency arithmetic, gaps, outputs, review and revisions. Default local files. Propose monthly Routine only with late-arrival rules. Do not automatically authorize writes, uploads, payments, external delivery or Bot contact.

Expected: A reusable method and review queue.
Check: Reruns/backfills are recorded without overwriting originals or confirmed history.