diff --git a/integration-tests/variable_write_test.go b/integration-tests/variable_write_test.go
index b3f5be3b..2a4be8c0 100644
--- a/integration-tests/variable_write_test.go
+++ b/integration-tests/variable_write_test.go
@@ -98,6 +98,23 @@ func TestVariableCreate(t *testing.T) {
 	assertTrimmed(t, "false", f.Run("var:get", "-p", p, "env:TEST", "-l", "p", "-P", "visible_runtime"))
 }
 
+func TestVariableCreateDefaultEnvironment(t *testing.T) {
+	// Regression test for CLI-164: using "-e ." (the default-environment code)
+	// must not fail form validation of the --environment option.
+	s := setupVariableTest(t)
+	s.apiHandler.SetEnvironments([]*mockapi.Environment{s.mainEnv})
+
+	f, p := s.factory, s.projectID
+
+	_, stdErr, err := f.RunCombinedOutput("var:create", "-p", p, "-e", ".", "-l", "e", "env:FOOBAR", "--value", "bar foo")
+	assert.NoError(t, err)
+	assert.Contains(t, stdErr, "Selecting default environment")
+	assert.Contains(t, stdErr, "Creating variable env:FOOBAR on the environment main")
+	assert.NotContains(t, stdErr, "is not one of")
+
+	assertTrimmed(t, "bar foo", f.Run("var:get", "-p", p, "-e", "main", "env:FOOBAR", "-P", "value"))
+}
+
 func TestVariableCreateWithAppScope(t *testing.T) {
 	s := setupVariableTest(t)
 
diff --git a/legacy/src/Command/Variable/VariableCreateCommand.php b/legacy/src/Command/Variable/VariableCreateCommand.php
index 2e2ce2b5..aa425cdb 100644
--- a/legacy/src/Command/Variable/VariableCreateCommand.php
+++ b/legacy/src/Command/Variable/VariableCreateCommand.php
@@ -64,6 +64,14 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         $selection = $this->selector->getSelection($input, new SelectorConfig(envRequired: false));
         $this->selection = $selection;
 
+        // The 'environment' form field validates the --environment option
+        // against the list of environment IDs. Replace the default-environment
+        // placeholder ('.') with the resolved environment ID so validation
+        // succeeds. See CLI-164.
+        if ($selection->hasEnvironment() && $input->getOption('environment') === Selector::DEFAULT_ENVIRONMENT_CODE) {
+            $input->setOption('environment', $selection->getEnvironment()->id);
+        }
+
         // Merge the 'name' argument with the --name option.
         if ($input->getArgument('name')) {
             if ($input->getOption('name')) {