Supplier outstanding balance (AP outstanding)

# Instructions — Calculating supplier outstanding (AP outstanding)

## ⚠️ Critical rule

The `amount` field of a payable is **always the total invoice amount**, never reduced by partial payments.
`paymentStatus=toPay` includes **partially paid** invoices — do not sum `amount` directly.

**Correct formula**: for each `toPay` payable, the actual outstanding = `amount.amount - sum(allocations[].amount.amount)`

## Step 1 — Retrieve unpaid payables

Call `get_payables` with:
```
filters: { field: "paymentStatus", operator: "=", value: ["toPay"] }
```

Paginate if `hasNextPage=true`.

## Step 2 — For each payable, calculate the true remaining balance

```
For each payable p:
  allocations_sum = sum(p.allocations[i].amount.amount)
  actual_outstanding = p.amount.amount - allocations_sum
  outstanding_decimal = actual_outstanding / 10^p.amount.precision
```

Examples of real cases encountered:
- Payable with allocations `[+11,106, -11,106]` → net = 0 → outstanding = 0 (payment then revision)
- Payable with allocations `[]` → outstanding = total amount → unpaid invoice
- Payable with allocation `[-250,000]` on a credit note of `-300,000` → 50,000 still to apply

## Step 3 — Aggregate in functional currency

**Careful**: amounts are in various currencies. Use `functionalAmount` (in the company's functional currency) for aggregation, not `amount` (invoice currency).

Calculate `functional_outstanding` = `functionalAmount.amount - sum(functional_allocations)`.

## Step 4 — Summary

Display:
- Total outstanding in functional currency
- Number of invoices involved
- Top 5 suppliers by outstanding amount
- Flag payables with complex allocations (revisions, partial credit notes)

## Example prompts

- "What is our total supplier outstanding?"
- "How much do we still owe suppliers this month?"