diff --git a/open-sse/executors/default.js b/open-sse/executors/default.js
index db5a290a..1297c351 100644
--- a/open-sse/executors/default.js
+++ b/open-sse/executors/default.js
@@ -13,6 +13,13 @@ export class DefaultExecutor extends BaseExecutor {
 
   transformRequest(model, body) {
     const transformed = this.applyJsonSchemaFallback(body);
+
+    if (transformed && typeof transformed === "object") {
+      if (this.provider === "cerebras" || this.provider === "mistral") {
+        delete transformed.client_metadata;
+      }
+    }
+
     return injectReasoningContent({ provider: this.provider, model, body: transformed });
   }