diff --git a/mini_agent/llm/anthropic_client.py b/mini_agent/llm/anthropic_client.py
index 5859c8d..a8c3af3 100644
--- a/mini_agent/llm/anthropic_client.py
+++ b/mini_agent/llm/anthropic_client.py
@@ -42,6 +42,7 @@ def __init__(
         self.client = anthropic.AsyncAnthropic(
             base_url=api_base,
             api_key=api_key,
+            default_headers={"Authorization": f"Bearer {api_key}"},
         )
 
     async def _make_api_request(