---
name: "books_depreciate"
area: "books"
title: "Book depreciation"
price: "$0.01"
method: "POST"
url: "https://api.conecto.chat/v1/tools/books_depreciate"
mcp_server: "https://api.conecto.chat/mcp/books"
auth: "Authorization: Bearer <conecto_sk_ key>"
docs_url: "https://conecto.chat/tools/books/books_depreciate"
---

# Book depreciation (`books_depreciate`)

Books the depreciation of every registered asset through a month's end, one entry a month, like Xero's run depreciation; or undoes it after a date.

Book the depreciation of every registered asset through a month's end (default: the end of last month), like Xero's run depreciation: one entry per month, dated its last day, from the month after the last one booked, so running it again books nothing twice. Months in a locked period are refused; catch_up: true books them in the first open month instead. undo_after books the opposite of what was booked for the months after that date, for every asset or the one asset names; undo before changing an asset's cost, life or method.

Price: $0.01 a call. A call that fails costs nothing.

## Use it when

At each month's end before locking it, after registering an asset bought earlier, or before changing an asset's cost, life or method (undo_after).

## Say this to your agent

> Book this year's depreciation through September.

## Inputs

| Name | Type | Required | Description | Allowed values | Default |
|---|---|---|---|---|---|
| `through` | string | no | YYYY-MM-DD (matches ^\\d{4}-\\d{2}-\\d{2}$) |  |  |
| `catch_up` | boolean | no |  |  | `false` |
| `undo_after` | string | no | Undo the months after this date. Matches ^\\d{4}-\\d{2}-\\d{2}$. |  |  |
| `asset` | string | no | Only this asset. 1 to 20 characters. |  |  |

## Example

Written for Hansen & Voss, a restaurant-equipment wholesaler in Hamburg with 60 staff.

MCP: call `books_depreciate` on the MCP server `https://api.conecto.chat/mcp/books` with these arguments:

```json
{
  "through": "2026-09-30"
}
```

REST:

```bash
curl https://api.conecto.chat/v1/tools/books_depreciate \
  -H "Authorization: Bearer $CONECTO_KEY" \
  -H "Content-Type: application/json" \
  -d '{"through": "2026-09-30"}'
```

## Response

```json
{
  "call_id": "5f0c8a2e-3b7d-4c1e-9a64-2d8e1f7b0c93",
  "tool": "books_depreciate",
  "status": "succeeded",
  "replayed": false,
  "cost_usd": "$0.01",
  "balance_usd": "$19.75",
  "result": {
    "through": "2026-09-30",
    "entries": [
      {
        "entry": 3,
        "date": "2026-03-31",
        "total": "500.00",
        "memo": "Depreciation for March 2026: FA-0001"
      },
      {
        "entry": 4,
        "date": "2026-04-30",
        "total": "500.00",
        "memo": "Depreciation for April 2026: FA-0001"
      }
    ],
    "total": "4400.00",
    "assets": [
      {
        "number": "FA-0001",
        "name": "Service van",
        "amount": "3500.00",
        "depreciated_through": "2026-09-30"
      },
      {
        "number": "FA-0002",
        "name": "Combi steamer",
        "amount": "900.00",
        "depreciated_through": "2026-09-30"
      }
    ]
  }
}
```

`result`: through (or undone_after), entries: each entry with its date, total and memo, total, and assets: what each asset got and the month it is depreciated through now.

## Errors

| Code | Status | When | Fix |
|---|---|---|---|
| `no_books` | 409 | The business keeps no books yet. | Set them up with books_setup (base currency, start date). |
| `invalid_input` | 400 | through is after the end of this month, or a date is not like 2026-09-30. | Use the end of this month or earlier. |
| `not_found` | 404 | No asset has that number. | List them with books_list_assets. |
| `period_locked` | 409 | Months to book fall in a locked period. | Pass catch_up: true to book them in the first open month, or unlock with books_lock. |
| `asset_disposed` | 409 | The asset named, or one with depreciation after undo_after, was sold or written off. | Undo the sale with books_dispose_asset undo first. |

The refusals every tool can give (401 key, 402 balance, 429 limits) are on the errors page: https://conecto.chat/docs/errors.md

## Related

- [books_setup](https://conecto.chat/tools/books/books_setup.md): Starts the business's double-entry books (currency, start date, chart of accounts) or changes their settings. $0.001 a call.
- [books_get](https://conecto.chat/tools/books/books_get.md): The books' settings: currency, start date, fiscal year, locked period, roles, payment accounts, taxes, and what is waiting. Free up to 1,000,000 reads a month.
- [books_list_accounts](https://conecto.chat/tools/books/books_list_accounts.md): Every account with its code, type, role and balance on a day. Free up to 1,000,000 reads a month.
- [books_save_accounts](https://conecto.chat/tools/books/books_save_accounts.md): Adds accounts or changes them, matched by code: name, type, description, code, role or archived. $0.001 a call.
- [books_save_tax](https://conecto.chat/tools/books/books_save_tax.md): Adds or changes a tax rate the books use (VAT, GST, sales tax), matched by name. $0.001 a call.
- [books_record_expense](https://conecto.chat/tools/books/books_record_expense.md): Books a cost the business paid, with its tax split off and the receipt attached. $0.01 a call.
- [books_record_entry](https://conecto.chat/tools/books/books_record_entry.md): Books a journal entry of two or more balancing lines, for whatever the other tools do not cover. $0.01 a call.
- [books_attach_receipt](https://conecto.chat/tools/books/books_attach_receipt.md): Attaches a receipt from the file store to an entry that has none. $0.01 a call.
- [books_reverse_entry](https://conecto.chat/tools/books/books_reverse_entry.md): Undoes an entry by booking its mirror image; entries are never edited or deleted. $0.01 a call.
- [books_list_entries](https://conecto.chat/tools/books/books_list_entries.md): Entries, newest first, with their lines, by dates, account, source or text. Free up to 1,000,000 reads a month.
- [books_import_bank](https://conecto.chat/tools/books/books_import_bank.md): Reads a bank statement from the file store (CSV, CAMT.053 or OFX) onto a bank account, skipping lines imported before. Free.
- [books_bank_lines](https://conecto.chat/tools/books/books_bank_lines.md): Imported bank lines (by default the ones still to match), each with up to three suggestions of what it was. Free up to 1,000,000 reads a month.
- [books_match_bank_lines](https://conecto.chat/tools/books/books_match_bank_lines.md): Says what bank lines were: entries already booked, invoices or bills they pay, an account to book them to, or nothing to book. $0.02 per bank line matched.
- [books_save_bank_rule](https://conecto.chat/tools/books/books_save_bank_rule.md): Saves a bank rule, like Xero's: which new bank lines it matches and how they are booked, to one account or split by percent, each part with its own tax. $0.001 a call.
- [books_list_bank_rules](https://conecto.chat/tools/books/books_list_bank_rules.md): Lists the bank rules in the order they are tried, with where they book and how often they were used. Free up to 1,000,000 reads a month.
- [books_apply_bank_rules](https://conecto.chat/tools/books/books_apply_bank_rules.md): Books every new bank line a rule matches, each by the first rule that matches. $0.02 per bank line booked.
- [books_delete_bank_rule](https://conecto.chat/tools/books/books_delete_bank_rule.md): Deletes a bank rule; what it booked stays booked. Free.
- [books_report](https://conecto.chat/tools/books/books_report.md): A report: profit and loss, balance sheet, trial balance, ledger, tax, the VAT or OSS return, the cash flow ahead or a snapshot of the business. Free up to 1,000,000 reads a month.
- [books_save_tracking](https://conecto.chat/tools/books/books_save_tracking.md): Saves a tracking category with its options, like Xero's: a department, a region or a project line that any line of the books can carry. $0.001 a call.
- [books_list_tracking](https://conecto.chat/tools/books/books_list_tracking.md): Lists the tracking categories and their options. Free up to 1,000,000 reads a month.
- [books_save_budget](https://conecto.chat/tools/books/books_save_budget.md): Saves a budget per income and expense account and month, like Xero's budget manager: amounts, monthly or yearly. $0.001 a call.
- [books_list_budgets](https://conecto.chat/tools/books/books_list_budgets.md): Lists the budgets with every line's monthly amounts and total. Free up to 1,000,000 reads a month.
- [books_delete_budget](https://conecto.chat/tools/books/books_delete_budget.md): Deletes a budget; the books don't change. Free.
- [books_repay_claims](https://conecto.chat/tools/books/books_repay_claims.md): Pays someone back for costs they paid with their own money (expense claims), like Xero's, with a SEPA file when asked. $0.01 a call.
- [books_list_claims](https://conecto.chat/tools/books/books_list_claims.md): Lists expense claims: what people paid for the business privately, and what each is owed. Free up to 1,000,000 reads a month.
- [books_save_asset](https://conecto.chat/tools/books/books_save_asset.md): Registers a fixed asset (a van, a machine) and how it depreciates, like Xero's: straight line, declining balance, at once or not at all. $0.001 a call.
- [books_list_assets](https://conecto.chat/tools/books/books_list_assets.md): The fixed asset register: each asset's cost, accumulated depreciation and book value, what a run would book now, and the register held against the books. Free up to 1,000,000 reads a month.
- [books_dispose_asset](https://conecto.chat/tools/books/books_dispose_asset.md): Sells or writes off a fixed asset, like Xero's dispose: depreciation to the day it goes, then its cost, the price and the gain or loss. $0.01 a call.
- [books_delete_asset](https://conecto.chat/tools/books/books_delete_asset.md): Takes an asset registered by mistake out of the register; the books don't change. Free.
- [books_lock](https://conecto.chat/tools/books/books_lock.md): Locks the books through a date, so nothing new is booked on or before it; null unlocks. $0.001 a call.
- [books_close_year](https://conecto.chat/tools/books/books_close_year.md): Closes a fiscal year for good: nothing is booked on or before its last day again, and it can't be undone. $0.001 a call.
- [books_export](https://conecto.chat/tools/books/books_export.md): A CSV of the journal or the accounts, a DATEV Buchungsstapel for a German tax adviser or a French FEC, with a download link. $0.001 a call.