diff --git a/src/Lean/Elab/Frontend.lean b/src/Lean/Elab/Frontend.lean
index c2b85a511e..fbffcb803e 100644
--- a/src/Lean/Elab/Frontend.lean
+++ b/src/Lean/Elab/Frontend.lean
@@ -94,10 +94,10 @@ def getPrintMessageEndPos (opts : Options) : Bool :=
   opts.getBool `printMessageEndPos false
 
 @[export lean_run_frontend]
-def runFrontend (input : String) (opts : Options) (fileName : String) (mainModuleName : Name) : IO (Environment × Bool) := do
+def runFrontend (input : String) (opts : Options) (fileName : String) (mainModuleName : Name) (trustLevel : UInt32 := 0) : IO (Environment × Bool) := do
   let inputCtx := Parser.mkInputContext input fileName
   let (header, parserState, messages) ← Parser.parseHeader inputCtx
-  let (env, messages) ← processHeader header opts messages inputCtx
+  let (env, messages) ← processHeader header opts messages inputCtx trustLevel
   let env := env.setMainModule mainModuleName
   let s ← IO.processCommands inputCtx parserState (Command.mkState env messages opts)
   for msg in s.commandState.messages.toList do
diff --git a/src/util/shell.cpp b/src/util/shell.cpp
index 5c1a537e7e..921f9cffce 100644
--- a/src/util/shell.cpp
+++ b/src/util/shell.cpp
@@ -336,10 +336,10 @@ void load_library(std::string path) {
 }
 
 namespace lean {
-extern "C" object * lean_run_frontend(object * input, object * opts, object * filename, object * main_module_name, object * w);
-pair_ref<environment, object_ref> run_new_frontend(std::string const & input, options const & opts, std::string const & file_name, name const & main_module_name) {
+extern "C" object * lean_run_frontend(object * input, object * opts, object * filename, object * main_module_name, uint32_t trust_level, object * w);
+pair_ref<environment, object_ref> run_new_frontend(std::string const & input, options const & opts, std::string const & file_name, name const & main_module_name, uint32_t trust_level) {
     return get_io_result<pair_ref<environment, object_ref>>(
-        lean_run_frontend(mk_string(input), opts.to_obj_arg(), mk_string(file_name), main_module_name.to_obj_arg(), io_mk_world()));
+        lean_run_frontend(mk_string(input), opts.to_obj_arg(), mk_string(file_name), main_module_name.to_obj_arg(), trust_level, io_mk_world()));
 }
 
 /* def workerMain : Options → IO UInt32 */
@@ -647,7 +647,7 @@ extern "C" LEAN_EXPORT int lean_main(int argc, char ** argv) {
 
         if (!main_module_name)
             main_module_name = name("_stdin");
-        pair_ref<environment, object_ref> r = run_new_frontend(contents, opts, mod_fn, *main_module_name);
+        pair_ref<environment, object_ref> r = run_new_frontend(contents, opts, mod_fn, *main_module_name, trust_lvl);
         env = r.fst();
         bool ok = unbox(r.snd().raw());