diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 2ae31acf8..c8e1721e3 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -231,9 +231,11 @@ export namespace ProviderTransform {
 
     if (model.api.npm === "@ai-sdk/google" || model.api.npm === "@ai-sdk/google-vertex") {
       result["thinkingConfig"] = {
-        thinkingLevel: "high",
         includeThoughts: true,
       }
+      if (model.api.id.includes("gemini-3")) {
+        result["thinkingConfig"]["thinkingLevel"] = "high"
+      }
     }
 
     if (model.api.id.includes("gpt-5") && !model.api.id.includes("gpt-5-chat")) {