diff --git a/api/src/opentrons/protocol_engine/types.py b/api/src/opentrons/protocol_engine/types.py
index a7a9e5f0a04..77ab6231b71 100644
--- a/api/src/opentrons/protocol_engine/types.py
+++ b/api/src/opentrons/protocol_engine/types.py
@@ -885,12 +885,14 @@ def from_hw_state(cls, state: HwTipStateType) -> "TipPresenceStatus":
 class RTPBase(BaseModel):
     """Parameters defined in a protocol."""
 
-    displayName: str = Field(..., description="Display string for the parameter.")
-    variableName: str = Field(..., description="Python variable name of the parameter.")
-    description: Optional[str] = Field(
+    displayName: StrictStr = Field(..., description="Display string for the parameter.")
+    variableName: StrictStr = Field(
+        ..., description="Python variable name of the parameter."
+    )
+    description: Optional[StrictStr] = Field(
         None, description="Detailed description of the parameter."
     )
-    suffix: Optional[str] = Field(
+    suffix: Optional[StrictStr] = Field(
         None,
         description="Units (like mL, mm/sec, etc) or a custom suffix for the parameter.",
     )