diff --git a/services/wallet-service/internal/service/wallet/usecase/gift/service.go b/services/wallet-service/internal/service/wallet/usecase/gift/service.go
index aede63f9..daf2619f 100644
--- a/services/wallet-service/internal/service/wallet/usecase/gift/service.go
+++ b/services/wallet-service/internal/service/wallet/usecase/gift/service.go
@@ -37,7 +37,10 @@ func (s *Service) DebitRobotGift(ctx context.Context, command ledger.DebitGiftCo
 }
 
 func (s *Service) debitGift(ctx context.Context, command ledger.DebitGiftCommand) (ledger.Receipt, error) {
-	if command.CommandID == "" || command.RoomID == "" || command.SenderUserID <= 0 || command.TargetUserID <= 0 || command.GiftID == "" {
+	roomIDRequired := !command.DirectGift
+	if command.CommandID == "" || (roomIDRequired && command.RoomID == "") || command.SenderUserID <= 0 || command.TargetUserID <= 0 || command.GiftID == "" {
+		// 房间送礼必须带 RoomID，让 Room Cell、账务分录和房间 outbox 能共享同一个业务边界。
+		// 私聊送礼没有房间状态 owner；DirectGift 使用独立 biz_type 和 request hash 隔离幂等，因此允许 RoomID 为空。
 		return ledger.Receipt{}, xerr.New(xerr.InvalidArgument, "billing command is incomplete")
 	}
 	if command.GiftCount <= 0 {
diff --git a/services/wallet-service/internal/service/wallet/usecase/gift/service_test.go b/services/wallet-service/internal/service/wallet/usecase/gift/service_test.go
new file mode 100644
index 00000000..67dab08d
--- /dev/null
+++ b/services/wallet-service/internal/service/wallet/usecase/gift/service_test.go
@@ -0,0 +1,65 @@
+package gift
+
+import (
+	"context"
+	"testing"
+
+	"hyapp/pkg/xerr"
+	"hyapp/services/wallet-service/internal/domain/ledger"
+)
+
+type fakeGiftLedgerStore struct {
+	debitCalls int
+	lastDebit  ledger.DebitGiftCommand
+}
+
+func (f *fakeGiftLedgerStore) DebitGift(_ context.Context, command ledger.DebitGiftCommand) (ledger.Receipt, error) {
+	f.debitCalls++
+	f.lastDebit = command
+	return ledger.Receipt{TransactionID: "tx-direct"}, nil
+}
+
+func (f *fakeGiftLedgerStore) BatchDebitGift(_ context.Context, _ ledger.BatchDebitGiftCommand) (ledger.BatchGiftReceipt, error) {
+	return ledger.BatchGiftReceipt{}, nil
+}
+
+func TestDebitGiftAllowsDirectGiftWithoutRoomID(t *testing.T) {
+	store := &fakeGiftLedgerStore{}
+	svc := New(store)
+
+	_, err := svc.DebitGift(context.Background(), ledger.DebitGiftCommand{
+		AppCode:      "lalu",
+		CommandID:    "cmd-direct-gift",
+		DirectGift:   true,
+		SenderUserID: 10001,
+		TargetUserID: 10002,
+		GiftID:       "rose",
+		GiftCount:    1,
+	})
+	if err != nil {
+		t.Fatalf("direct gift without room_id must reach repository: %v", err)
+	}
+	if store.debitCalls != 1 || !store.lastDebit.DirectGift || store.lastDebit.RoomID != "" {
+		t.Fatalf("direct gift command was not preserved: calls=%d command=%+v", store.debitCalls, store.lastDebit)
+	}
+}
+
+func TestDebitGiftRequiresRoomIDForRoomGift(t *testing.T) {
+	store := &fakeGiftLedgerStore{}
+	svc := New(store)
+
+	_, err := svc.DebitGift(context.Background(), ledger.DebitGiftCommand{
+		AppCode:      "lalu",
+		CommandID:    "cmd-room-gift",
+		SenderUserID: 10001,
+		TargetUserID: 10002,
+		GiftID:       "rose",
+		GiftCount:    1,
+	})
+	if !xerr.IsCode(err, xerr.InvalidArgument) {
+		t.Fatalf("room gift without room_id must be invalid argument, got %v", err)
+	}
+	if store.debitCalls != 0 {
+		t.Fatalf("invalid room gift must not reach repository, calls=%d", store.debitCalls)
+	}
+}