diff --git a/src/mcp/server/lowlevel/server.py b/src/mcp/server/lowlevel/server.py
index 3fc2d497..7c516964 100644
--- a/src/mcp/server/lowlevel/server.py
+++ b/src/mcp/server/lowlevel/server.py
@@ -499,7 +499,7 @@ class Server(Generic[LifespanResultT, RequestT]):
 
         def decorator(
             func: Callable[
-                ...,
+                [str, dict[str, Any]],
                 Awaitable[
                     UnstructuredContent
                     | StructuredContent