diff --git a/src/mcp/client/session.py b/src/mcp/client/session.py
index c1cc5b5fc..49545ad90 100644
--- a/src/mcp/client/session.py
+++ b/src/mcp/client/session.py
@@ -219,7 +219,7 @@ async def unsubscribe_resource(self, uri: AnyUrl) -> types.EmptyResult:
         )
 
     async def call_tool(
-        self, name: str, arguments: dict | None = None
+        self, name: str, arguments: dict[str, Any] | None = None
     ) -> types.CallToolResult:
         """Send a tools/call request."""
         return await self.send_request(
diff --git a/src/mcp/server/fastmcp/tools/base.py b/src/mcp/server/fastmcp/tools/base.py
index a8751a5f1..28afc211e 100644
--- a/src/mcp/server/fastmcp/tools/base.py
+++ b/src/mcp/server/fastmcp/tools/base.py
@@ -68,7 +68,9 @@ def from_function(
             context_kwarg=context_kwarg,
         )
 
-    async def run(self, arguments: dict, context: "Context | None" = None) -> Any:
+    async def run(
+        self, arguments: dict[str, Any], context: "Context | None" = None
+    ) -> Any:
         """Run the tool with arguments."""
         try:
             return await self.fn_metadata.call_fn_with_arg_validation(
diff --git a/src/mcp/server/fastmcp/tools/tool_manager.py b/src/mcp/server/fastmcp/tools/tool_manager.py
index 807c26b0c..57528f0d3 100644
--- a/src/mcp/server/fastmcp/tools/tool_manager.py
+++ b/src/mcp/server/fastmcp/tools/tool_manager.py
@@ -43,7 +43,7 @@ def add_tool(
         return tool
 
     async def call_tool(
-        self, name: str, arguments: dict, context: "Context | None" = None
+        self, name: str, arguments: dict[str, Any], context: "Context | None" = None
     ) -> Any:
         """Call a tool by name with arguments."""
         tool = self.get_tool(name)