When you change a transaction's category in the web app, Lunch Money can automatically create a rule for that payee if the "Auto-create rule when updating category" setting is enabled. The developer API's PUT /transactions/{id} endpoint doesn't do this today, even when the setting is on.

Please add an opt-in request parameter on the transaction update endpoint (something like auto_create_rules: true) that, when passed, triggers the same rule-creation behavior the web app uses: it matches on the payee's bank-feed name, uses the new category as the rule's action, and respects the existing account-level setting (so if you've turned the setting off, the flag is a no-op).

Adding this functionality with a new request body property should preserve the existing behavior by default.