diff --git a/lib/model_context_protocol/transports/stdio.rb b/lib/model_context_protocol/transports/stdio.rb
index 1c158d0f..f72508b4 100644
--- a/lib/model_context_protocol/transports/stdio.rb
+++ b/lib/model_context_protocol/transports/stdio.rb
@@ -9,6 +9,8 @@ class StdioTransport < Transport
       def initialize(server)
         @server = server
         @open = false
+        $stdin.set_encoding("UTF-8")
+        $stdout.set_encoding("UTF-8")
         super
       end