diff --git a/internal/transport/interceptors.go b/internal/transport/interceptors.go
index 10f1a01..bbb2f3f 100644
--- a/internal/transport/interceptors.go
+++ b/internal/transport/interceptors.go
@@ -2,6 +2,7 @@ package transport
 
 import (
 	"context"
+	sessionv1 "git.sch9.ru/new_gate/ms-tester/pkg/go/gen/session/v1"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
@@ -15,11 +16,22 @@ func (s *TesterServer) AuthInterceptor() grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
 		reqWithToken, ok := req.(ReqWithToken)
 		if !ok {
-			return nil, status.Errorf(codes.Unknown, "") // FIXME
+			return nil, status.Errorf(codes.Unauthenticated, "") // FIXME
 		}
 
 		token := reqWithToken.GetToken()
 
+		if token == "" {
+			return nil, status.Errorf(codes.Unauthenticated, "") // FIXME
+		}
+
+		userId, err := s.sessionClient.Read(ctx, &sessionv1.ReadSessionRequest{Token: token})
+		if err != nil {
+			return nil, status.Errorf(codes.Unauthenticated, "") // FIXME
+		}
+
+		ctx = context.WithValue(ctx, "user_id", userId)
+
 		return handler(ctx, req)
 	}
 }
diff --git a/internal/transport/server.go b/internal/transport/server.go
index a4fd78b..165fc66 100644
--- a/internal/transport/server.go
+++ b/internal/transport/server.go
@@ -3,6 +3,7 @@ package transport
 import (
 	"context"
 	"git.sch9.ru/new_gate/ms-tester/internal/models"
+	sessionv1 "git.sch9.ru/new_gate/ms-tester/pkg/go/gen/session/v1"
 	testerv1 "git.sch9.ru/new_gate/ms-tester/pkg/go/gen/tester/v1"
 	"go.uber.org/zap"
 	"google.golang.org/protobuf/types/known/timestamppb"
@@ -18,22 +19,39 @@ type ProblemService interface {
 	DeleteProblem(ctx context.Context, id int32) error
 }
 
+type SessionClient interface {
+	Read(ctx context.Context,
+		in *sessionv1.ReadSessionRequest,
+		opts ...grpc.CallOption,
+	) (*sessionv1.ReadSessionResponse, error)
+}
+
 type TesterServer struct {
 	testerv1.UnimplementedTesterServiceServer
 	problemService ProblemService
 
-	gRPCServer *grpc.Server
+	sessionClient SessionClient
+
+	grpcServer *grpc.Server
 	logger     *zap.Logger
 }
 
-func NewTesterServer(problemService ProblemService, gRPCServer *grpc.Server, logger *zap.Logger) *TesterServer {
+func NewTesterServer(
+	problemService ProblemService,
+	sessionServer SessionClient,
+	logger *zap.Logger,
+) *TesterServer {
 	server := &TesterServer{
 		problemService: problemService,
-		gRPCServer:     gRPCServer,
+		sessionClient:  sessionServer,
 		logger:         logger,
 	}
 
-	testerv1.RegisterTesterServiceServer(gRPCServer, server)
+	grpcServer := grpc.NewServer(
+		grpc.UnaryInterceptor(server.AuthInterceptor()),
+	)
+
+	testerv1.RegisterTesterServiceServer(grpcServer, server)
 
 	return server
 }