diff --git a/core/llm/autodetect.ts b/core/llm/autodetect.ts
index 2bf3b10e16d..d9a49c1cd65 100644
--- a/core/llm/autodetect.ts
+++ b/core/llm/autodetect.ts
@@ -144,7 +144,11 @@ function modelSupportsReasoning(
   if (!model) {
     return false;
   }
-  if ("anthropic" === model.underlyingProviderName) {
+  if (
+    model.model.includes("claude") &&
+    !model.model.includes("-3-") &&
+    !model.model.includes("-3.5-")
+  ) {
     return true;
   }
   if (model.model.includes("deepseek-r")) {