diff --git a/server/server.go b/server/server.go
index 3ffe286..88fed09 100644
--- a/server/server.go
+++ b/server/server.go
@@ -168,6 +168,9 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	r.Header.Set("X-Request-Id", rid)
 	w.Header().Set("X-Request-Id", rid)
 
+	// http://www.gnuterrypratchett.com/
+	w.Header().Set("X-Clacks-Overhead", "GNU Terry Pratchett")
+
 	if strings.HasSuffix(r.Host, ".onion") {
 		w.Header().Add("DNT", "1")
 	}