Add OcrResponse schema and tighten invoice validation

- Adds OcrResponse Pydantic schema for OCR branch JSON output.

- Validates invoice_date and due_date as strict ISO 8601 calendar dates.

- Adds field descriptions to InvoiceLineItem for clearer VLM prompts.

- Expands schema tests for dates, decimal coercion, negatives, and line_items_sum().

src/odoo_ocr/schemas/__init__.py

@@ -1,12 +1,13 @@
 """Pydantic schemas for the Odoo OCR pipeline."""
 
-from .document import DocumentClass, ProcessingContext
+from .document import DocumentClass, OcrResponse, ProcessingContext
 from .invoice import ExtractedInvoice, InvoiceLineItem
 from .review import ReviewIssue, ReviewResult
 from .vlm import VLMResponse
 
 __all__ = [
     "DocumentClass",
+    "OcrResponse",
     "ProcessingContext",
     "ExtractedInvoice",
     "InvoiceLineItem",

src/odoo_ocr/schemas/document.py

@@ -6,7 +6,7 @@ from enum import StrEnum
 from pathlib import Path
 from typing import Any
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
 
 
 class DocumentClass(StrEnum):
@@ -26,6 +26,18 @@ class ClassificationResult(BaseModel):
     reasoning: str = ""
 
 
+class OcrResponse(BaseModel):
+    """Output of the OCR branch models.
+
+    The OCR system prompt instructs the model to return a JSON object with a
+    single ``text`` field containing the full page OCR output.
+    """
+
+    model_config = ConfigDict(str_strip_whitespace=True)
+
+    text: str
+
+
 class ProcessingContext(BaseModel):
     """Mutable-ish context passed through pipeline stages.
 

src/odoo_ocr/schemas/invoice.py

@@ -2,10 +2,28 @@
 
 from __future__ import annotations
 
+import re
+from datetime import date
 from decimal import Decimal
 from typing import Any
 
-from pydantic import BaseModel, ConfigDict, Field, field_validator
+from pydantic import BaseModel, ConfigDict, Field, ValidationInfo, field_validator
+
+_ISO_DATE_RE = re.compile(r"^\d{4}-\d{2}-\d{2}$")
+
+
+def _validate_iso_date(value: Any, field_name: str | None) -> str | None:
+    if value is None:
+        return None
+    text = str(value).strip()
+    label = field_name or "date"
+    if not _ISO_DATE_RE.match(text):
+        raise ValueError(f"{label} must be an ISO 8601 date (YYYY-MM-DD), got: {value!r}")
+    try:
+        date.fromisoformat(text)
+    except ValueError as exc:
+        raise ValueError(f"{label} is not a valid calendar date: {value!r}") from exc
+    return text
 
 
 class InvoiceLineItem(BaseModel):
@@ -13,11 +31,19 @@ class InvoiceLineItem(BaseModel):
 
     model_config = ConfigDict(str_strip_whitespace=True)
 
-    description: str
-    quantity: Decimal = Field(default=Decimal("1"), ge=Decimal("0"))
-    unit_price: Decimal = Field(default=Decimal("0"), ge=Decimal("0"))
-    total_price: Decimal = Field(default=Decimal("0"), ge=Decimal("0"))
-    tax_rate: Decimal = Field(default=Decimal("0"), ge=Decimal("0"))
+    description: str = Field(description="Description of the product or service.")
+    quantity: Decimal = Field(
+        default=Decimal("1"), ge=Decimal("0"), description="Quantity invoiced."
+    )
+    unit_price: Decimal = Field(
+        default=Decimal("0"), ge=Decimal("0"), description="Price per unit before tax."
+    )
+    total_price: Decimal = Field(
+        default=Decimal("0"), ge=Decimal("0"), description="Line total before tax."
+    )
+    tax_rate: Decimal = Field(
+        default=Decimal("0"), ge=Decimal("0"), description="Tax rate as a percentage, e.g. 20 for 20%."
+    )
 
     @field_validator("quantity", "unit_price", "total_price", "tax_rate", mode="before")
     @classmethod
@@ -47,6 +73,11 @@ class ExtractedInvoice(BaseModel):
     iban: str | None = None
     raw_ocr_text: str = ""
 
+    @field_validator("invoice_date", "due_date", mode="before")
+    @classmethod
+    def _validate_dates(cls, value: Any, info: ValidationInfo) -> str | None:
+        return _validate_iso_date(value, info.field_name)
+
     @field_validator("subtotal", "tax_total", "total", mode="before")
     @classmethod
     def _coerce_decimal(cls, value: Any) -> Decimal:

tests/test_schemas.py

@@ -0,0 +1,84 @@
+"""Tests for invoice schema validation."""
+
+from __future__ import annotations
+
+from decimal import Decimal
+
+import pytest
+from pydantic import ValidationError
+
+from odoo_ocr.schemas import ExtractedInvoice, InvoiceLineItem
+
+
+def test_accepts_valid_iso_dates() -> None:
+    invoice = ExtractedInvoice(
+        vendor_name="A",
+        invoice_number="1",
+        invoice_date="2024-01-01",
+        due_date="2024-02-01",
+    )
+    assert invoice.invoice_date == "2024-01-01"
+    assert invoice.due_date == "2024-02-01"
+
+
+def test_rejects_non_iso_date_format() -> None:
+    with pytest.raises(ValidationError, match="ISO 8601"):
+        ExtractedInvoice(
+            vendor_name="A",
+            invoice_number="1",
+            invoice_date="May 1, 2024",
+        )
+
+
+def test_rejects_invalid_calendar_date() -> None:
+    with pytest.raises(ValidationError, match="not a valid calendar date"):
+        ExtractedInvoice(
+            vendor_name="A",
+            invoice_number="1",
+            invoice_date="2024-02-30",
+        )
+
+
+def test_due_date_optional() -> None:
+    invoice = ExtractedInvoice(
+        vendor_name="A",
+        invoice_number="1",
+        invoice_date="2024-01-01",
+    )
+    assert invoice.due_date is None
+
+
+def test_invoice_line_item_decimal_coercion() -> None:
+    line = InvoiceLineItem(
+        description="Widgets",
+        quantity="2",
+        unit_price="10.5",
+        total_price="21.0",
+        tax_rate="20",
+    )
+    assert line.quantity == Decimal("2")
+    assert line.unit_price == Decimal("10.5")
+    assert line.total_price == Decimal("21.0")
+    assert line.tax_rate == Decimal("20")
+
+
+def test_invoice_line_item_rejects_negative_values() -> None:
+    with pytest.raises(ValidationError):
+        InvoiceLineItem(description="X", quantity=-1)
+    with pytest.raises(ValidationError):
+        InvoiceLineItem(description="X", unit_price=-1)
+    with pytest.raises(ValidationError):
+        InvoiceLineItem(description="X", tax_rate=-5)
+
+
+def test_line_items_sum() -> None:
+    invoice = ExtractedInvoice(
+        vendor_name="A",
+        invoice_number="1",
+        invoice_date="2024-01-01",
+        line_items=[
+            InvoiceLineItem(description="X", total_price=Decimal("100")),
+            InvoiceLineItem(description="Y", total_price=Decimal("50.50")),
+        ],
+    )
+    assert invoice.line_items_sum() == Decimal("150.50")