diff --git a/backend/internal/service/gateway_service.go b/backend/internal/service/gateway_service.go
index d8e72859f9..7004891623 100644
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -1436,11 +1436,11 @@ func (s *GatewayService) buildOAuthMetadataUserIDFromBody(
 // accountID 恒存在，故 seed 永不为空 —— 输出始终是确定性 UUID，而非随机值。
 func buildStableSessionSeed(accountID int64, clientDiscriminator, firstUserText string) string {
 	var b strings.Builder
-	b.WriteString(strconv.FormatInt(accountID, 10))
-	b.WriteString("::")
-	b.WriteString(clientDiscriminator)
-	b.WriteString("::")
-	b.WriteString(firstUserText)
+	_, _ = b.WriteString(strconv.FormatInt(accountID, 10))
+	_, _ = b.WriteString("::")
+	_, _ = b.WriteString(clientDiscriminator)
+	_, _ = b.WriteString("::")
+	_, _ = b.WriteString(firstUserText)
 	return b.String()
 }
 
diff --git a/backend/internal/service/openai_codex_transform_additions_test.go b/backend/internal/service/openai_codex_transform_additions_test.go
index 6f5026edf0..fee4551346 100644
--- a/backend/internal/service/openai_codex_transform_additions_test.go
+++ b/backend/internal/service/openai_codex_transform_additions_test.go
@@ -53,7 +53,7 @@ func TestApplyCodexClientMetadata(t *testing.T) {
 	// 既有 client_metadata（如 turn metadata）保留，仅补 installation 键
 	body3 := map[string]any{"client_metadata": map[string]any{"x-codex-turn-metadata": "t"}}
 	require.True(t, applyCodexClientMetadata(body3, acc))
-	cm3 := body3["client_metadata"].(map[string]any)
+	cm3, _ := body3["client_metadata"].(map[string]any)
 	require.Equal(t, "t", cm3["x-codex-turn-metadata"])
 	require.Equal(t, "dev-xyz", cm3["x-codex-installation-id"])
 }
diff --git a/backend/internal/service/openai_gateway_service.go b/backend/internal/service/openai_gateway_service.go
index 7bf17aeeb9..1cb19ea727 100644
--- a/backend/internal/service/openai_gateway_service.go
+++ b/backend/internal/service/openai_gateway_service.go
@@ -45,7 +45,7 @@ const (
 	// 与真实 Codex CLI 的 User-Agent 结构对齐：
 	// {originator}/{version} ({OS} {OS_version}; {arch}) {terminal}
 	// 旧值 "codex_cli_rs/0.125.0" 缺少 OS/架构/终端后缀，易被上游指纹识别为非官方客户端。
-	codexCLIUserAgent      = "codex_cli_rs/0.125.0 (Ubuntu 22.4.0; x86_64) xterm-256color"
+	codexCLIUserAgent = "codex_cli_rs/0.125.0 (Ubuntu 22.4.0; x86_64) xterm-256color"
 	// codex_cli_only 拒绝时单个请求头日志长度上限（字符）
 	codexCLIOnlyHeaderValueMaxBytes = 256