diff --git a/backend/windmill-worker/src/ai/providers/openai.rs b/backend/windmill-worker/src/ai/providers/openai.rs
index 178f3b23a4..5cf745693a 100644
--- a/backend/windmill-worker/src/ai/providers/openai.rs
+++ b/backend/windmill-worker/src/ai/providers/openai.rs
@@ -147,7 +147,15 @@ impl OpenAIQueryBuilder {
             .map(|props| !props.is_empty())
             .unwrap_or(false);
 
-        let response_format = if has_output_properties && args.output_schema.is_some() {
+        let should_use_structured_output_tool =
+            should_use_structured_output_tool(&self.provider_kind, args.model);
+
+        // Only use response_format for providers that support it (not Claude/Anthropic)
+        // Claude models use a tool for structured output instead
+        let response_format = if has_output_properties
+            && args.output_schema.is_some()
+            && !should_use_structured_output_tool
+        {
             let schema = args.output_schema.unwrap();
             let strict_schema = schema.clone().make_strict();
             Some(ResponseFormat {
@@ -162,10 +170,8 @@ impl OpenAIQueryBuilder {
             None
         };
 
-        let should_use_structured_output_tool =
-            should_use_structured_output_tool(&self.provider_kind, args.model);
-        // Force usage of structured output tool for Claude models when structured output provided
-        let tool_choice = if should_use_structured_output_tool && response_format.is_some() {
+        // Force usage of structured output tool for Claude models when structured output is provided
+        let tool_choice = if should_use_structured_output_tool && has_output_properties {
             Some(ToolChoice::Required)
         } else {
             None