# tax.adjustments.update

Record reviewed regular-method GST/HST adjustments, instalments, rebates and self-assessments in CAD minor units, with reason, source evidence, revision and the current ledger snapshot. This does not remit tax or file a return.

`POST /api/v1/accounting/tax.adjustments.update`

Permissions: `accounting:read`, `accounting:write` · Roles: admin, finance · Idempotency key required · Send `expectedRevision`

Not available over MCP: Accountants' corrections grant isn't offered over MCP yet: phase 1 is read and comment only.

## Fields

| Field | Type | Required | Notes |
| --- | --- | --- | --- |
| `expectedRevision` | integer | Yes | The record's current revision, from the last time you read it. If someone changed the record since, the request is refused with a conflict so you can reload and check before trying again. 0 to 9007199254740991. |
| `idempotencyKey` | string | Yes | Any unique text you generate once per intended change, so a retried request only happens once. Send it as the Idempotency-Key header instead if you prefer; if you send both they must match. 8–200 characters. |
| `period` | object | Yes | The period to cover. No other fields. |
| `period.from` | string | Yes | The first date to include, as YYYY-MM-DD. |
| `period.to` | string | Yes | The last date to include, as YYYY-MM-DD. |
| `period.kind` | enum | Yes | Which kind of record or job this is. One of: `corporate`, `gst_hst`. |
| `line104Minor` | string | Yes | An amount in cents (the currency's smallest unit), written as a whole-number string such as "1250" for $12.50. Whole number written as a string. |
| `line107Minor` | string | Yes | An amount in cents (the currency's smallest unit), written as a whole-number string such as "1250" for $12.50. Whole number written as a string. |
| `line110Minor` | string | Yes | An amount in cents (the currency's smallest unit), written as a whole-number string such as "1250" for $12.50. Whole number written as a string. |
| `line111Minor` | string | Yes | An amount in cents (the currency's smallest unit), written as a whole-number string such as "1250" for $12.50. Whole number written as a string. |
| `line205Minor` | string | Yes | An amount in cents (the currency's smallest unit), written as a whole-number string such as "1250" for $12.50. Whole number written as a string. |
| `line405Minor` | string | Yes | An amount in cents (the currency's smallest unit), written as a whole-number string such as "1250" for $12.50. Whole number written as a string. |
| `reason` | string | Yes | A short note saying why, kept in the record's history. 3–2000 characters. |
| `snapshotHash` | string | Yes | SHA-256 hash as 64 lowercase hex characters. |
| `evidenceIds` | array of strings (ID) |  | A list of record IDs. at most 20 items. Default `[]`. |

## Example request

```bash
curl https://app.getoatmilk.com/api/v1/accounting/tax.adjustments.update \
  -H "Authorization: Bearer $OATMILK_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
  "expectedRevision": 3,
  "period": {
    "from": "2026-09-01",
    "to": "2026-09-30",
    "kind": "corporate"
  },
  "line104Minor": "1250",
  "line107Minor": "1250",
  "line110Minor": "1250",
  "line111Minor": "1250",
  "line205Minor": "1250",
  "line405Minor": "1250",
  "reason": "Synthetic example from the docs",
  "snapshotHash": "9f2b5c1d7e3a4b6c8d0e2f4a6b8c0d2e4f6a8b0c2d4e6f8a0b2c4d6e8f0a2b4c"
}'
```

Reference page: https://app.getoatmilk.com/docs/api/tax.adjustments.update