diff --git a/bin/evening_detective_server b/bin/evening_detective_server
index c08cbe1..0cf2b46 100755
Binary files a/bin/evening_detective_server and b/bin/evening_detective_server differ
diff --git a/internal/app/team_registration.go b/internal/app/team_registration.go
index 83446ec..f3f11bb 100644
--- a/internal/app/team_registration.go
+++ b/internal/app/team_registration.go
@@ -5,6 +5,7 @@ import (
 	"crypto/subtle"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"strconv"
@@ -41,11 +42,16 @@ func TeamRegistrationHandler(token string, register func(context.Context, int, s
 		decoder.DisallowUnknownFields()
 		var registration game_service.Registration
 		if err := decoder.Decode(&registration); err != nil {
-			fail(http.StatusBadRequest, "Некорректный JSON регистрации")
+			fail(http.StatusBadRequest, fmt.Sprintf("Некорректный JSON регистрации: %v", err))
 			return
 		}
-		if err := decoder.Decode(new(any)); err != io.EOF {
-			fail(http.StatusBadRequest, "Ожидается один JSON-объект")
+		var extra any
+		if err := decoder.Decode(&extra); err != io.EOF {
+			if err == nil {
+				fail(http.StatusBadRequest, "Некорректный JSON регистрации: после объекта обнаружены лишние данные")
+			} else {
+				fail(http.StatusBadRequest, fmt.Sprintf("Некорректный JSON регистрации: после объекта обнаружены лишние данные: %v", err))
+			}
 			return
 		}
 		ctx, cancel := context.WithTimeout(r.Context(), 4*time.Second)
diff --git a/internal/app/team_registration_test.go b/internal/app/team_registration_test.go
index e8133d9..7d8ba4a 100644
--- a/internal/app/team_registration_test.go
+++ b/internal/app/team_registration_test.go
@@ -61,6 +61,15 @@ func TestTeamRegistrationHandler(t *testing.T) {
 			if strings.Contains(res.Body.String(), "private database detail") {
 				t.Fatal("private error exposed")
 			}
+			if tc.name == "malformed" && !strings.Contains(res.Body.String(), "unexpected EOF") {
+				t.Fatalf("malformed JSON reason missing: %s", res.Body.String())
+			}
+			if tc.name == "unknown field" && !strings.Contains(res.Body.String(), "unknown field") {
+				t.Fatalf("unknown field reason missing: %s", res.Body.String())
+			}
+			if tc.name == "extra object" && !strings.Contains(res.Body.String(), "лишние данные") {
+				t.Fatalf("extra data reason missing: %s", res.Body.String())
+			}
 		})
 	}
 }