diff --git a/langstream-agents/langstream-agent-http-request/src/main/java/ai/langstream/agents/http/LangServeClient.java b/langstream-agents/langstream-agent-http-request/src/main/java/ai/langstream/agents/http/LangServeClient.java
index c77b4ce96..da1444927 100644
--- a/langstream-agents/langstream-agent-http-request/src/main/java/ai/langstream/agents/http/LangServeClient.java
+++ b/langstream-agents/langstream-agent-http-request/src/main/java/ai/langstream/agents/http/LangServeClient.java
@@ -267,7 +267,7 @@ interface StreamingChunksConsumer {
 
     private String buildBody(Map<String, Object> values) throws IOException {
         Map<String, Object> request = Map.of("input", values);
-        return mapper.writeValueAsString(request);
+        return ObjectMapperFactory.getDefaultMapper().writeValueAsString(request);
     }
 
     public CompletableFuture<String> execute(