diff --git a/codersdk/parameters.go b/codersdk/parameters.go
index 073efafb63fbb..57df03d56077a 100644
--- a/codersdk/parameters.go
+++ b/codersdk/parameters.go
@@ -72,7 +72,7 @@ type ParameterSchema struct {
 
 	// This is a special array of items provided if the validation condition
 	// explicitly states the value must be one of a set.
-	ValidationContains []string `json:"validation_contains"`
+	ValidationContains []string `json:"validation_contains,omitempty"`
 }
 
 // CreateParameterRequest is used to create a new parameter value for a scope.
diff --git a/site/src/api/typesGenerated.ts b/site/src/api/typesGenerated.ts
index 61415137f3483..bb031235455b7 100644
--- a/site/src/api/typesGenerated.ts
+++ b/site/src/api/typesGenerated.ts
@@ -190,7 +190,7 @@ export interface ParameterSchema {
   readonly validation_condition: string
   readonly validation_type_system: string
   readonly validation_value_type: string
-  readonly validation_contains: string[]
+  readonly validation_contains?: string[]
 }
 
 // From codersdk/provisionerdaemons.go:33:6
diff --git a/site/src/components/ParameterInput/ParameterInput.tsx b/site/src/components/ParameterInput/ParameterInput.tsx
index a12d3c07f012d..638acdac7a35b 100644
--- a/site/src/components/ParameterInput/ParameterInput.tsx
+++ b/site/src/components/ParameterInput/ParameterInput.tsx
@@ -29,7 +29,7 @@ export const ParameterInput: FC<ParameterInputProps> = ({ disabled, onChange, sc
 }
 
 const ParameterField: React.FC<ParameterInputProps> = ({ disabled, onChange, schema }) => {
-  if (schema.validation_contains.length > 0) {
+  if (schema.validation_contains && schema.validation_contains.length > 0) {
     return (
       <RadioGroup
         defaultValue={schema.default_source_value}