Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

CI: mypy type errors resolved (no behavior change). SGLineItem.line_allowances, SGInvoice.tax_lines, SGInvoice.allowances_charges, and SGInvoice.line_items (models/invoice.py) narrow their base class’s field type to a jurisdiction-specific subclass — the intended, documented subclassing pattern (see the root CLAUDE.md’s “Canonical invoice tree” rules) — but list is invariant, so mypy’s structural check flags the narrowing; annotated # type: ignore[assignment] on each, matching the same pattern already used in mcp-cfdi-mx. IRASC5Validator.validate (validators/schematron.py) replaced a bare, unparameterized metadata: dict local with typed locals (rulesets_run: list[str], scope: str) assembled into the returned metadata dict, avoiding dict’s missing type-arguments error. ci.yml’s mypy step has no continue-on-error for this package (unlike most others in the fleet), so these were live CI failures, not documented pre-existing debt.

Resolves all 8 findings from the first SG compliance audit (audit/2026-08-audit-sg.md).

SGInvoice model validator (_require_document_uuid_for_gst_sg) requiring document_uuid (cbc:UUID, BT-SG-003) whenever any tax line/line item/allowance uses a GST category in the new SG_BR108_GST_SG_CATEGORIES constant (BR-108-GST-SG) — SG-SC-1 (HIGH).
SGInvoice model validator (_require_party_uens) requiring both seller.uen and buyer.uen (IRASC5-026/IRASC5-034) — SG-SH-1.
cbc:TaxCurrencyCode="SGD" emission (BR-53 position) whenever currency_code differs from SGD — SG-TC-1.
server.py registers core’s register_peppol_tools with an SG id adapter (scheme 0195, bare UEN) — SG-LC-2.
_INTENTIONAL_OVERRIDES populated in audit/audit_vs_core.py across 13 core modules — SG-AG-1. Audit gate: 0 blocking / 0 warnings.

document_uuid migrated onto core’s own EN16931Invoice.document_uuid field (core >=1.25.0); the SG-specific invoice_uuid field and its manual serializer insertion are removed — SGUBLSerializer no longer builds cbc:UUID itself.
currency_code widened from a fixed "SGD" Literal to any 3-letter ISO 4217 shape (still defaulting to SGD) — SG-TC-1.
server.py’s MCP instructions corrected to match the already-accurate validate_invoice_sg tool docstring (IRAS C5 acceptance layer only, UBL 2.1 XSD structural validation NOT checked) — SG-SC-2.
Core dependency floor bumped to mcp-einvoicing-core>=1.26.0,<2.0.0 (needed for the _build_party UBL 2.1 element-ordering fix).

[Confirmed] Core’s EN16931UBLSerializer._build_party emitted cac:Party children out of UBL 2.1 xsd:sequence order — fixed in mcp-einvoicing-core v1.26.0 (see that package’s changelog). Proved via a new test-only XSD-validation test that SG’s own serializer output is genuinely UBL 2.1-valid once the core fix is applied (SG-SC-3, partial — see below).

SG-SC-3 stays partial. UBL 2.1 XSD structural validation is proven via a test-only regression (tests/fixtures/ubl-2.1/) but is not wired into production validate_invoice_sg or shipped in the wheel: the OASIS UBL 2.1 schema files carry no locally-confirmed redistribution grant, following the same precedent mcp-einvoicing-ae set in v0.2.0 when it removed a bundled peppol-tdd-1.0.0.xsd. Tracked as [NEED: OASIS UBL 2.1 redistribution grant] in context-library/roadmap-2026.md.

Removed unlicensed bundled Peppol/PINT-SG Schematron overlay. PINT-jurisdiction-aligned-rules.xslt and PINT-UBL-validation- preprocessed.xslt (compiled from OpenPeppol’s PINT-jurisdiction-aligned- rules.sch / PINT-UBL-validation-preprocessed.sch) were bundled and shipped in the v0.1.0 wheel with no confirmed redistribution rights — the same absence of license context-library/decisions/peppol-schematron- artifact.md found for mcp-einvoicing-be/mcp-ksef-pl’s Peppol BIS 3.0 overlay. Both files are removed; validate_invoice_sg no longer compiles or ships any OpenPeppol-derived Schematron content.

validate_invoice_sg now runs IRAS’s own C5 acceptance layer only. The CEN EN16931 base ruleset is wired (en16931_base_schematron_validator(), shared with mcp-einvoicing-be/mcp-ksef-pl) but deliberately not activated: SGInvoice’s IRAS GST category codes (SR/ZR/ES33/…) have no sourced crosswalk to the UNCL5305 code list the base ruleset’s BR-CL-17 requires. See EN16931_BASE_UNAVAILABLE_WARNING in every result and [CORE-EN16931-BASE-SG-CROSSWALK-1] in context-library/roadmap-2026.md for what would unblock it.
Known coverage loss: PINT-SG’s own jurisdiction rules (e.g. the invoice_uuid/BR-108-GST-SG requirement) are no longer checked by validate_invoice_sg. This is a real, deliberate reduction in validation coverage, not a defect — see EN16931_BASE_UNAVAILABLE_WARNING and result.metadata["scope"].

First release. PINT-SG v1.4.1 / SG Peppol BIS Billing 3.0 sent-invoice support.

SGInvoice(EN16931Invoice) model (TX2_Annex Annex B Type 1A), SGParty (UEN, validated via TaxIdentifier.validate_sg_uen(), core >=1.24.0), GST category codes narrowed to IRAS Annex E, invoice_uuid (BT-SG-003 jurisdiction extension field), and a business_process/profile matched-pair check (TX2_Annex Annex A/B).
SGUBLSerializer — UBL 2.1 output (GST TaxScheme, UEN, UUID emission).
SGDocumentValidator — PINT-SG Schematron (base + jurisdiction) plus IRAS’s own C5 acceptance layer.
4 MCP tools: generate_invoice_sg, validate_invoice_sg, get_gst_category_codes_sg, get_profile_urn_sg.

Ordering-family models (Order/OrderResponse/etc.).
IRAS Access Point submission client — no publicly available document states an AP’s actual base URL/auth flow.
SG Peppol BIS Billing 3.0 Schematron — ships only raw ISO Schematron source, no pre-compiled XSLT.

See specs/README.md and the monorepo’s context-library/countries/sg.md for full detail and citations.