diff --git a/http.go b/http.go
index d8cfc1f..af5e70f 100644
--- a/http.go
+++ b/http.go
@@ -16,6 +16,8 @@ import (
 // and use CopyTo() instead.
 type Request struct {
 	// Request header
+	//
+	// Copying Header by value is forbidden. Use pointer to Header instead.
 	Header RequestHeader
 
 	body []byte
@@ -36,6 +38,8 @@ type Request struct {
 // and use CopyTo() instead.
 type Response struct {
 	// Response header
+	//
+	// Copying Header by value is forbidden. Use pointer to Header instead.
 	Header ResponseHeader
 
 	body []byte
diff --git a/server.go b/server.go
index 28e3674..395ed25 100644
--- a/server.go
+++ b/server.go
@@ -219,9 +219,13 @@ func TimeoutHandler(h RequestHandler, timeout time.Duration, msg string) Request
 // before return.
 type RequestCtx struct {
 	// Incoming request.
+	//
+	// Copying Request by value is forbidden. Use pointer to Request instead.
 	Request Request
 
 	// Outgoing response.
+	//
+	// Copying Response by value is forbidden. Use pointer to Response instead.
 	Response Response
 
 	id uint64