diff --git a/pylib/gyp/generator/compile_commands_json.py b/pylib/gyp/generator/compile_commands_json.py
index 276cba0a..900b4395 100644
--- a/pylib/gyp/generator/compile_commands_json.py
+++ b/pylib/gyp/generator/compile_commands_json.py
@@ -42,7 +42,7 @@ def CalculateVariables(default_variables, params):
 
 
 def AddCommandsForTarget(cwd, target, params, per_config_commands):
-    output_dir = params["generator_flags"]["output_dir"]
+    output_dir = params["generator_flags"].get("output_dir", "out")
     for configuration_name, configuration in target["configurations"].items():
         builddir_name = os.path.join(output_dir, configuration_name)
 
@@ -110,7 +110,7 @@ def GenerateOutput(target_list, target_dicts, data, params):
         cwd = os.path.dirname(build_file)
         AddCommandsForTarget(cwd, target, params, per_config_commands)
 
-    output_dir = params["generator_flags"]["output_dir"]
+    output_dir = params["generator_flags"].get("output_dir", "out")
     for configuration_name, commands in per_config_commands.items():
         filename = os.path.join(output_dir, configuration_name, "compile_commands.json")
         gyp.common.EnsureDirExists(filename)