diff --git a/agents/core-logic/agent.py b/agents/core-logic/agent.py
index a31a226..46c6c8d 100644
--- a/agents/core-logic/agent.py
+++ b/agents/core-logic/agent.py
@@ -88,7 +88,7 @@ def _identity_token() -> str:
 
 def _mcp_headers() -> dict:
     return {
-        "X-MCP-Secret": _MCP_SECRET,
+        "X-MCP-Key": _MCP_SECRET,
         "Content-Type": "application/json",
     }
 
diff --git a/agents/core-logic/root_agent.py b/agents/core-logic/root_agent.py
index 8dea654..573bfbb 100644
--- a/agents/core-logic/root_agent.py
+++ b/agents/core-logic/root_agent.py
@@ -73,7 +73,7 @@ def _identity_token() -> str:
 
 def _mcp_headers() -> dict:
     return {
-        "X-MCP-Secret": _MCP_SECRET,
+        "X-MCP-Key": _MCP_SECRET,
         "Content-Type": "application/json",
     }