Implement AI orchestration wedding demo

backend/app/validation/action_validator.py

@@ -0,0 +1,35 @@
+from jsonschema import Draft202012Validator, FormatChecker
+from pydantic import ValidationError
+
+from app.domain.schemas import PlannerDecision, ValidationResult
+from app.ai.tool_registry import ToolRegistry
+
+
+class ActionValidator:
+    def __init__(self, registry: ToolRegistry) -> None:
+        self.registry = registry
+
+    def validate(self, decision: PlannerDecision) -> ValidationResult:
+        if decision.intent == "no_action":
+            return ValidationResult(valid=False, errors=["No actionable intent detected."])
+        if not decision.tool:
+            return ValidationResult(valid=False, errors=["Planner did not select a tool."])
+        tool = self.registry.get(decision.tool)
+        if not tool:
+            return ValidationResult(valid=False, errors=[f"Unknown tool: {decision.tool}"])
+        try:
+            Draft202012Validator(tool.schema, format_checker=FormatChecker()).validate(decision.arguments)
+        except Exception as exc:
+            return ValidationResult(valid=False, errors=[str(exc)])
+        extra = set(decision.arguments) - set(tool.schema.get("properties", {}))
+        if extra:
+            return ValidationResult(valid=False, errors=[f"Hallucinated parameters: {sorted(extra)}"])
+        try:
+            self._validate_dates(decision.arguments)
+        except ValidationError as exc:
+            return ValidationResult(valid=False, errors=[str(exc)])
+        return ValidationResult(valid=True)
+
+    def _validate_dates(self, args: dict) -> None:
+        # JSON Schema catches shape; FastAPI/Pydantic validates API models at execution time.
+        return None