diff --git a/mcp/tools.go b/mcp/tools.go
index 51145337..5ee9fedb 100644
--- a/mcp/tools.go
+++ b/mcp/tools.go
@@ -504,7 +504,9 @@ func (r *CallToolResult) UnmarshalJSON(data []byte) error {
 	// Unmarshal Meta
 	if meta, ok := raw["_meta"]; ok {
 		if metaMap, ok := meta.(map[string]any); ok {
-			r.Meta = metaMap
+			r.Meta = &Meta{
+				AdditionalFields: metaMap,
+			}
 		}
 	}
 
diff --git a/server/stdio.go b/server/stdio.go
index 4d567d8c..3fdb09fd 100644
--- a/server/stdio.go
+++ b/server/stdio.go
@@ -2,6 +2,7 @@ package server
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -457,11 +458,18 @@ func (s *StdioServer) writeResponse(
 	response mcp.JSONRPCMessage,
 	writer io.Writer,
 ) error {
-	responseBytes, err := json.Marshal(response)
-	if err != nil {
+	// Create a buffer to write JSON with custom encoding settings
+	var buf bytes.Buffer
+	encoder := json.NewEncoder(&buf)
+	encoder.SetEscapeHTML(false) // Disable HTML escaping, which also prevents Unicode escaping
+	
+	if err := encoder.Encode(response); err != nil {
 		return err
 	}
 
+	// Remove the trailing newline added by Encode() and add our own
+	responseBytes := bytes.TrimSuffix(buf.Bytes(), []byte("\n"))
+	
 	// Write response followed by newline
 	if _, err := fmt.Fprintf(writer, "%s\n", responseBytes); err != nil {
 		return err