diff --git a/applications/abri/abri_trigger_request.py b/applications/abri/abri_trigger_request.py
index d159105c7..0a9346ca9 100644
--- a/applications/abri/abri_trigger_request.py
+++ b/applications/abri/abri_trigger_request.py
@@ -7,22 +7,38 @@ visibility surface.
 """
 
 from datetime import date
-from typing import Any, List, Literal, Optional
+from typing import Dict, List, Literal, Optional, Tuple
 
-from pydantic import BaseModel, ConfigDict
+from pydantic import BaseModel, ConfigDict, Field, model_validator
 
 AbriFlow = Literal["amend_job", "log_job", "sync_tenant_data"]
 
+# The deal fields each flow reads; hubspot_deal_id is always required.
+_FIELDS_BY_FLOW: Dict[AbriFlow, Tuple[str, ...]] = {
+    "amend_job": ("confirmed_survey_date",),
+    "log_job": ("place_ref", "deal_name", "confirmed_survey_date"),
+    "sync_tenant_data": ("place_ref",),
+}
+
 
 class AbriTriggerRequest(BaseModel):
     model_config = ConfigDict(extra="ignore")
 
     hubspot_deal_id: str
-    flows: List[AbriFlow]
+    flows: List[AbriFlow] = Field(min_length=1)
     place_ref: Optional[str] = None
     deal_name: Optional[str] = None
     confirmed_survey_date: Optional[date] = None
     confirmed_survey_time: Optional[str] = None
 
-    def model_post_init(self, __context: Any) -> None:
-        raise NotImplementedError
+    @model_validator(mode="after")
+    def _each_fired_flow_has_its_fields(self) -> "AbriTriggerRequest":
+        missing = [
+            f"flow {flow} requires {field}"
+            for flow in self.flows
+            for field in _FIELDS_BY_FLOW[flow]
+            if getattr(self, field) is None
+        ]
+        if missing:
+            raise ValueError("; ".join(missing))
+        return self