A Fortnox user with OSS sales hit the SIE import mapping step and found no
way to map OSS accounts: the momskod picker had no OSS option, 3106-style
labels ("Försäljning varor till annat EU-land, momspliktig") were suggested
as EU-varor (ruta 35), and an OSS revenue account with a sats set leaked into
ruta 05. Skatteverket: "Den försäljning som du redovisar i OSS ska du inte
redovisa i den vanliga momsdeklarationen."
- add the 'oss' revenue treatment: allowed for class 3 only, mapped to no
ruta, default rate null (destination-country rate is not a Swedish sats);
explicit 'oss' also overrides static BAS mappings such as 3001
- REVENUE_RUTA becomes a partial map where null = allowed but off the
declaration, so the class gate no longer conflates "no ruta" with
"purchase-only"
- SIE label suggestion: OSS/unionsordningen labels suggest 'oss';
momspliktig EU-varor labels are left for review instead of ruta 35
- AccountVatTreatmentSchema derives from ACCOUNT_VAT_TREATMENTS instead of a
second literal list
- migration widens the class-aware CHECK with 'oss' for class 3 (superset;
NOT VALID + VALIDATE like its predecessor); pg test extended
- sv/en labels; unit tests for resolver, suggestion, declaration exclusion
Per-country VAT rates on invoices and the quarterly EUR/ECB OSS underlag
remain unbuilt (DECISIONS.md).
Claude-Session: https://claude.ai/code/session_01E3QB8GxJ9tS217agHjLRk7
Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Jakob Wennberg
51c815254a