diff --git a/agents/core-logic/agent.py b/agents/core-logic/agent.py
index 8979047..86e0f10 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-Key": _MCP_SECRET.strip(),
+        "X-MCP-Secret": _MCP_SECRET.strip(),
         "Content-Type": "application/json",
     }
 
diff --git a/agents/core-logic/root_agent.py b/agents/core-logic/root_agent.py
index b8fc38d..be10601 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-Key": _MCP_SECRET.strip(),
+        "X-MCP-Secret": _MCP_SECRET.strip(),
         "Content-Type": "application/json",
     }