diff --git a/R/model.R b/R/model.R
index f55c23be..7f298b11 100644
--- a/R/model.R
+++ b/R/model.R
@@ -634,6 +634,8 @@ compile <- function(quiet = TRUE,
   }
   stancflags_standalone <- c("--standalone-functions", stancflags_val, stancflags_combined)
   self$functions$hpp_code <- get_standalone_hpp(temp_stan_file, stancflags_standalone)
+  private$model_methods_env_ <- new.env()
+  private$model_methods_env_$hpp_code_ <- get_standalone_hpp(temp_stan_file, c(stancflags_val, stancflags_combined))
   self$functions$external <- !is.null(user_header)
   self$functions$existing_exe <- FALSE
 
@@ -720,10 +722,8 @@ compile <- function(quiet = TRUE,
   private$precompile_cpp_options_ <- NULL
   private$precompile_stanc_options_ <- NULL
   private$precompile_include_paths_ <- NULL
-  private$model_methods_env_ <- new.env()
 
   if(!dry_run) {
-    suppressWarnings(private$model_methods_env_$hpp_code_ <- readLines(private$hpp_file_, warn = FALSE))
     if (compile_model_methods) {
       expose_model_methods(env = private$model_methods_env_,
                             verbose = !quiet,
diff --git a/R/utils.R b/R/utils.R
index a2f1fc43..00fe3fae 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -800,6 +800,10 @@ create_skeleton <- function(param_metadata, model_variables,
 }
 
 get_standalone_hpp <- function(stan_file, stancflags) {
+  name <- strip_ext(basename(stan_file))
+  path <- dirname(stan_file)
+  hpp_path <- file.path(path, paste0(name, ".hpp"))
+
   status <- withr::with_path(
       c(
         toolchain_PATH_env_var(),
@@ -807,16 +811,12 @@ get_standalone_hpp <- function(stan_file, stancflags) {
       ),
       wsl_compatible_run(
         command = stanc_cmd(),
-        args = c(stan_file,
-                stancflags),
+        args = c(paste0("--o=", hpp_path), stancflags, stan_file),
         wd = cmdstan_path(),
         error_on_status = FALSE
       )
     )
   if (status$status == 0) {
-    name <- strip_ext(basename(stan_file))
-    path <- dirname(stan_file)
-    hpp_path <- file.path(path, paste0(name, ".hpp"))
     hpp <- suppressWarnings(readLines(hpp_path, warn = FALSE))
     unlink(hpp_path)
     hpp