diff --git a/backend/internal/session_manager/manager.go b/backend/internal/session_manager/manager.go
index e840fdc06..c0119587f 100644
--- a/backend/internal/session_manager/manager.go
+++ b/backend/internal/session_manager/manager.go
@@ -1160,7 +1160,8 @@ Before editing, identify which repository owns the task and keep changes scoped
 }
 
 func workspaceRepoList(repos []domain.WorkspaceRepoRecord) string {
-	lines := []string{fmt.Sprintf("- %s: .", domain.RootWorkspaceRepoName)}
+	lines := make([]string, 0, 1+len(repos))
+	lines = append(lines, fmt.Sprintf("- %s: .", domain.RootWorkspaceRepoName))
 	for _, repo := range repos {
 		lines = append(lines, fmt.Sprintf("- %s: %s", repo.Name, repo.RelativePath))
 	}