Follow the advice from reviewer, to keep the request body optional.

Deven Chen · Deven Chen · commit 053e5d853742 · 2025-10-22T09:12:28.000+11:00
diff --git a/specification/cdn/resource-manager/Microsoft.Cdn/Cdn/RuleSet.tsp b/specification/cdn/resource-manager/Microsoft.Cdn/Cdn/RuleSet.tsp
@@ -53,6 +53,7 @@ interface RuleSets {
   @Azure.Core.useFinalStateVia("azure-async-operation")
   create is Azure.ResourceManager.Legacy.CreateOrReplaceAsync<
     RuleSet,
+    OptionalRequestBody = true,
     Response = ArmResponse<RuleSet> | (ArmCreatedResponse<RuleSet> &
       ArmAsyncOperationHeader<FinalResult = RuleSet> &
       ArmLroLocationHeader<FinalResult = RuleSet>) | ErrorResponse
diff --git a/specification/cdn/resource-manager/Microsoft.Cdn/Cdn/stable/2025-12-01/openapi.json b/specification/cdn/resource-manager/Microsoft.Cdn/Cdn/stable/2025-12-01/openapi.json
@@ -6850,7 +6850,7 @@
             "name": "resource",
             "in": "body",
             "description": "Resource create parameters.",
-            "required": true,
+            "required": false,
             "schema": {
               "$ref": "#/definitions/RuleSet"
             }

Original file line number	Diff line number	Diff line change
`@@ -6850,7 +6850,7 @@`
`6850`	`6850`	`"name": "resource",`
`6851`	`6851`	`"in": "body",`
`6852`	`6852`	`"description": "Resource create parameters.",`
`6853`		`- "required": true,`
	`6853`	`+ "required": false,`
`6854`	`6854`	`"schema": {`
`6855`	`6855`	`"$ref": "#/definitions/RuleSet"`
`6856`	`6856`	`}`