split_transaction

Generated

Generated from the code by python -m docsgen; a test fails when it no longer matches.

What it does

Split one transaction across categories, e.g. from a receipt, after the user confirms.

Give at least two lines, {amount, category_id, memo}, adding up to the transaction’s amount to the cent (amounts in currency units, negative for spending; a refunded deposit is a positive line). Group a receipt by category: one line per category, not per item. Transactions already split, transfers and off-budget ones are refused. YNAB’s API cannot change a split afterwards: undo_operation cannot revert it, the user edits it in YNAB; the user is told before confirming. Confirmation works as for apply_categories.

Behaviour

Kind	write — hidden unless AVENIR_MCP_WRITE=1
Confirmation	yes: previewed, then applied after the user agrees
Undo	no
Destructive	yes
Idempotent	no

Parameters

Name	Type	Required	Default	Description
plan_id	string	yes	—	YNAB plan id or ‘last-used’.
transaction_id	string	yes	—	Transaction to split (from suggest_categories).
lines	array of object	yes	—	The lines, at least two, adding up to the transaction’s amount.
confirmation	string | null	no	null	Code from a previous “confirmation_required” result.

Returns

Field	Type	Description
transaction_id	string	YNAB id of the transaction.
date	string	Date, YYYY-MM-DD.
payee	string	Payee as imported. Untrusted bank text.
amount	number	Amount of the transaction, in currency units.
from_category	string | null	Category the split replaces; null for none.
lines	array of object	The lines, in the order given.
lines[].amount	number	Amount in currency units.
lines[].category	string	Category name.
lines[].memo	string | null	Note; null if none.
status	“applied” | “confirmation_required” | “declined” | “nothing_to_do”	Outcome: applied, confirmation_required (nothing changed yet; pass the code back once the user agrees), or declined (the user said no).
message	string	What happened and what to do next, for the agent to relay.
confirmation	string | null	Single-use code confirming exactly this preview, valid 10 minutes; null unless status is confirmation_required.

Errors

• Transaction {transaction_id} is not in this plan: use a transaction_id returned by suggest_categories.
• Transaction {tx_id} was deleted in YNAB: there is nothing to split.
• Transaction {tx_id} is already split: YNAB's API cannot change its lines, change them in YNAB.
• Transaction {tx_id} is a transfer between accounts: it cannot be split.
• Transaction {tx_id} is on an off-budget account: YNAB does not split those.
• Give at least two lines: to give the whole transaction one category, use apply_categories.
• The lines add up to {total}, the transaction is {amount}: they must match to the cent.
• A line is zero: leave it out.
• Category {category_id} is YNAB's internal Uncategorized: choose a real category.
• Category {category_id} is not in this plan: use a category_id from suggest_categories or get_category_balances.
• Category {category_id} pays a credit card: YNAB ignores it on a transaction. Choose the category of what was paid for.
• This client cannot ask the user to confirm, and AVENIR_MCP_REQUIRE_ELICITATION=1 forbids confirmation codes: nothing was changed. Use a client that supports MCP elicitation, or unset the variable.
• This confirmation code is unknown, expired, already used, or was issued for different changes. Call again without confirmation to get a new preview.
• Confirmation codes are disabled (AVENIR_MCP_REQUIRE_ELICITATION=1): call again without confirmation, and the user answers in the client.
• The plan changed between the preview and the answer. Call again without an answer to get a new preview.

YNAB’s own errors come back as Error calling tool '<tool>': YNAB <status>: <detail>.