diff --git a/conan/cli/cli.py b/conan/cli/cli.py
index 5848c39be07..4961c2e4a8e 100644
--- a/conan/cli/cli.py
+++ b/conan/cli/cli.py
@@ -26,6 +26,7 @@ class Cli:
     parsing of parameters and delegates functionality to the conan python api. It can also show the
     help of the tool.
     """
+    _builtin_commands = None  # Caching the builtin commands, no need to load them over and over
 
     def __init__(self, conan_api):
         assert isinstance(conan_api, ConanAPI), \
@@ -35,10 +36,16 @@ def __init__(self, conan_api):
         self._commands = {}
 
     def _add_commands(self):
-        conan_commands_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "commands")
-        for module in pkgutil.iter_modules([conan_commands_path]):
-            module_name = module[1]
-            self._add_command("conan.cli.commands.{}".format(module_name), module_name)
+        if Cli._builtin_commands is None:
+            conan_cmd_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "commands")
+            for module in pkgutil.iter_modules([conan_cmd_path]):
+                module_name = module[1]
+                self._add_command("conan.cli.commands.{}".format(module_name), module_name)
+            Cli._builtin_commands = self._commands.copy()
+        else:
+            self._commands = Cli._builtin_commands.copy()
+            for k, v in self._commands.items():  # Fill groups data too
+                self._groups[v.group].append(k)
 
         custom_commands_path = HomePaths(self._conan_api.cache_folder).custom_commands_path
         if not os.path.isdir(custom_commands_path):
diff --git a/conans/test/integration/package_id/test_default_package_id.py b/conans/test/integration/package_id/test_default_package_id.py
index 323c8b48bf7..879befe242c 100644
--- a/conans/test/integration/package_id/test_default_package_id.py
+++ b/conans/test/integration/package_id/test_default_package_id.py
@@ -21,7 +21,7 @@ def test_default_package_id_options(typedep, typeconsumer, different_id):
     """ test that some consumer package ids are changed when the dependency change one of its
     options
     """
-    c = TestClient()
+    c = TestClient(light=True)
     dep = GenConanfile("dep", "0.1").with_option("myopt", [True, False]) \
         .with_package_type(typedep).with_class_attribute('implements = ["auto_shared_fpic", "auto_header_only"]')
     consumer = GenConanfile("consumer", "0.1").with_requires("dep/0.1")\
@@ -62,7 +62,7 @@ def test_default_package_id_options(typedep, typeconsumer, different_id):
 def test_default_package_id_versions(typedep, versiondep, typeconsumer, different_id):
     """ test that some consumer package ids are changed when the dependency changes its version
     """
-    c = TestClient()
+    c = TestClient(light=True)
     dep = GenConanfile("dep").with_package_type(typedep)
     consumer = GenConanfile("consumer", "0.1").with_requires("dep/[>0.0]") \
         .with_package_type(typeconsumer)
diff --git a/conans/test/utils/tools.py b/conans/test/utils/tools.py
index 700224c16f4..c1fd1c01057 100644
--- a/conans/test/utils/tools.py
+++ b/conans/test/utils/tools.py
@@ -373,7 +373,7 @@ class TestClient(object):
 
     def __init__(self, cache_folder=None, current_folder=None, servers=None, inputs=None,
                  requester_class=None, path_with_spaces=True,
-                 default_server_user=None):
+                 default_server_user=None, light=False):
         """
         current_folder: Current execution folder
         servers: dict of {remote_name: TestServer}
@@ -423,7 +423,11 @@ def __init__(self, cache_folder=None, current_folder=None, servers=None, inputs=
         self.inputs = inputs or []
 
         # create default profile
-        text = default_profiles[platform.system()]
+        if light:
+            text = "[settings]\nos=Linux"  # Needed at least build-os
+            save(self.cache.settings_path, "os: [Linux]")
+        else:
+            text = default_profiles[platform.system()]
         save(self.cache.default_profile_path, text)
 
     def load(self, filename):