List invoices in the accounts-payable ledger, optionally filtered by status or vendor. Returns compact summaries (id, vendor, PO, total, dates, status), sorted by id. Use this first to discover invoice ids. Read-only.

Fetch one invoice with its line items (sku, quantity, unit price in minor units) and any routing decision already recorded. Read-only. Errors with NOT_FOUND if the id is unknown.

Run a three-way match of an invoice against its purchase order and goods receipts. Checks vendor, currency, duplicates, dates, per-line quantity (vs ordered and received, net of already-approved invoices) and unit price, using tolerance rules. Returns an outcome (matched / matched_within_tolerance / exception), the list of findings with severity, and a recommended routing action and reason code. Read-only: it never changes the ledger. Call this before route_exception.

Record a routing decision for an invoice: approve, hold or reject, with a reason code. The server re-runs the match itself and enforces policy: approving an invoice with blocking findings is refused unless reasonCode=MANUAL_OVERRIDE, override=true and a note of 10+ chars (and duplicates can never be approved); reject needs a blocking finding with the same reason code; approved/rejected invoices are final. Idempotent: repeating the identical decision returns changed=false. Prefer "hold" when unsure, it is reversible. Changes the ledger.

Portfolio overview of the ledger: invoice counts and totals per status and currency, how many open (received or on_hold) invoices are past their due date, the oldest open invoice, and a tally of recorded decision reasons. Read-only. Use for "how are we doing" questions.