diff --git a/bin/cfg b/bin/cfg
index 2ce253f..3c7c0ef 100755
--- a/bin/cfg
+++ b/bin/cfg
@@ -22,59 +22,9 @@ foreach ($autoloadFiles as $autoloadFile) {
 	}
 }
 
-// Pre-parse site options so they can be passed after positional args.
-// The input helper library does not handle this case reliably.
-$preparsedSiteOptions = [];
-$rawArgv = $_SERVER['argv'] ?? $GLOBALS['argv'] ?? null;
-if (is_array($rawArgv) && !empty($rawArgv)) {
-	$filteredArgv = [$rawArgv[0]];
-	for ($idx = 1; $idx < count($rawArgv); $idx++) {
-		$arg = $rawArgv[$idx];
-
-		if ($arg === '-s' || $arg === '--site') {
-			$preparsedSiteOptions[] = [
-				'name' => 'site',
-				'value' => $rawArgv[$idx + 1] ?? '',
-			];
-			if (isset($rawArgv[$idx + 1])) $idx++;
-			continue;
-		}
-		if (str_starts_with($arg, '--site=')) {
-			$preparsedSiteOptions[] = [
-				'name' => 'site',
-				'value' => substr($arg, strlen('--site=')),
-			];
-			continue;
-		}
-
-		if ($arg === '--directory-name' || $arg === '--directoryName') {
-			$preparsedSiteOptions[] = [
-				'name' => 'directoryName',
-				'value' => $rawArgv[$idx + 1] ?? '',
-			];
-			if (isset($rawArgv[$idx + 1])) $idx++;
-			continue;
-		}
-		if (str_starts_with($arg, '--directory-name=')) {
-			$preparsedSiteOptions[] = [
-				'name' => 'directoryName',
-				'value' => substr($arg, strlen('--directory-name=')),
-			];
-			continue;
-		}
-		if (str_starts_with($arg, '--directoryName=')) {
-			$preparsedSiteOptions[] = [
-				'name' => 'directoryName',
-				'value' => substr($arg, strlen('--directoryName=')),
-			];
-			continue;
-		}
-
-		$filteredArgv[] = $arg;
-	}
-
-	$_SERVER['argv'] = $filteredArgv;
-	$GLOBALS['argv'] = $filteredArgv;
+function verboseLog(bool $enabled, string $message): void
+{
+	if ($enabled) fwrite(STDERR, "[verbose] $message".PHP_EOL);
 }
 
 $version = '0.4';
@@ -90,15 +40,55 @@ $collection = (new Input\InputCollection())
 		->description('Display help text')
 	) // }}}
 
-	->add( Input\InputTypeFactory::build('LongOption')->name('in')->short('i') // {{{
-		->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
-		->description('Path to a json data file to to read')
+	->add( Input\InputTypeFactory::build('LongOption')->name('verbose')->short('v') // {{{
+		->flags(AbstractInputType::FLAG_OPTIONAL)
+		->description('Print debug details to STDERR')
 	) // }}}
 
-	->add( Input\InputTypeFactory::build('LongOption')->name('out')->short('o') // {{{
-		->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
-		->description('Path to a json file to to write to')
-	) // }}}
+	->add( Input\InputTypeFactory::build('LongOption')->name('in')->short('i') // {{{
+			->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
+			->description('Path to a JSON data file to read (for write)')
+			->validator(new Input\Validator(
+				function (AbstractInputType $input, AbstractInputHandler $context)
+				{
+					$path = $context->find('in');
+					if ($path === null || $path === '') {
+						return null;
+					}
+
+					if (!is_readable($path))
+					{
+						throw new \Exception("Input file is not readable: $path");
+					}
+
+					$content = file_get_contents($path);
+					if ($content === false)
+					{
+						throw new \Exception("Can not read input file: $path");
+					}
+
+					try
+					{
+						$data = json_decode($content, true, 512, JSON_THROW_ON_ERROR);
+					}
+					catch (\JsonException $ex)
+					{
+						throw new \Exception(sprintf(
+							'Input JSON is invalid (%s): %s',
+							(string)$ex->getCode(),
+							$ex->getMessage()
+						));
+					}
+
+					if (!is_array($data))
+					{
+						throw new \Exception('Input JSON must decode to an object/array');
+					}
+
+					return $data;
+				}
+			))
+		) // }}}
 
 	->add( Input\InputTypeFactory::build('LongOption')->name('mode')->short('m') // {{{
 		->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
@@ -115,15 +105,59 @@ $collection = (new Input\InputCollection())
 		->description('Path where the config/ directory of the package conf files is located, defaults to the working dir')
 	) // }}}
 
-	->add( Input\InputTypeFactory::build('LongOption')->name('site')->short('s') // {{{
-		->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
-		->description('Site/instance directory below config/ (target: config/<site>/<prefix>.conf.php), e.g. owner_xyz')
-	) // }}}
+	->add( Input\InputTypeFactory::build('LongOption')->name('siteDir')->short('s') // {{{
+			->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
+			->description('Site/instance directory below config/. Accepts owner_xyz or config/owner_xyz')
+			->validator(new Input\Validator(
+				function (AbstractInputType $input, AbstractInputHandler $context)
+				{
+					$siteInput = $context->find('siteDir');
+					if ($siteInput === null || $siteInput === false) {
+						return null;
+					}
 
-	->add( Input\InputTypeFactory::build('LongOption')->name('directoryName') // {{{
-		->flags(AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_VALUE_REQUIRED)
-		->description('Alias for --site. Accepts owner_xyz or config/owner_xyz (also supports --directory-name)')
-	) // }}}
+					$siteInput = trim((string)$siteInput);
+					$appPath = $context->find('appPath');
+					if (!$appPath) {
+						$appPath = getcwd().'/';
+					}
+					$appPath = rtrim($appPath, '/').'/';
+
+					// Accept both "owner_xyz" and "config/owner_xyz" and normalize to site key.
+					if (str_starts_with($siteInput, $appPath.'config/'))
+					{
+						$siteInput = substr($siteInput, strlen($appPath.'config/'));
+					}
+					elseif (str_starts_with($siteInput, 'config/'))
+					{
+						$siteInput = substr($siteInput, strlen('config/'));
+					}
+
+					$siteInput = trim($siteInput, '/');
+					if ($siteInput === '')
+					{
+						throw new \Exception('Option --siteDir is empty.');
+					}
+
+					// Block directory traversal and hidden-dot segments.
+					if (str_contains($siteInput, '..') || preg_match('~(^|/)\.(?:/|$)~', $siteInput))
+					{
+						throw new \Exception("Invalid directory in --siteDir: '$siteInput'.");
+					}
+
+					// Allow only predictable path segments for instance directories.
+					foreach (explode('/', $siteInput) as $part)
+					{
+						if ($part === '' || !preg_match('/^[A-Za-z0-9._-]+$/', $part))
+						{
+							throw new \Exception("Invalid directory name segment '$part' in --siteDir.");
+						}
+					}
+
+					return $siteInput;
+				}
+			))
+		) // }}}
 
 	->add( Input\InputTypeFactory::build('Argument')->name('action') // {{{
 		->flags(AbstractInputType::FLAG_REQUIRED)
@@ -167,18 +201,30 @@ $collection = (new Input\InputCollection())
 		->description(
 			'the settings you want to work on. With action "write" you can pass the value to set as JSON after an equal sign.'
 		)
-		->validator(new Input\Validator(
-			function (AbstractInputType $input, AbstractInputHandler $context)
-			{
-				$setting = $context->find('setting');
-				$action = $context->find('action');
-				
+			->validator(new Input\Validator(
+				function (AbstractInputType $input, AbstractInputHandler $context)
+				{
+					$setting = $context->find('setting');
+						$action = $context->find('action');
+						$inputPayload = $context->find('in');
+
+						if ($action === 'write')
+						{
+							if (($setting !== null && $setting !== '') && $inputPayload) {
+								throw new \Exception('Please use either SETTING or --in, not both.');
+							}
+						}
+	
+					if ($setting === null || $setting === '') {
+						return ['key' => '', 'value' => null];
+					}
+
 				$setting = explode('=', $setting);
 				$settings['key'] = $setting[0];
 				if ($action === 'write')
 				{
-					$value = $setting[1];
-					if (! (isset($value) || $context->find('data'))) {
+					$value = $setting[1] ?? null;
+					if (! (isset($value) || $context->find('in'))) {
 						throw new \Exception('You need a value to write');
 					}
 					$specialValues = [ 'true', 'false', 'null' ];
@@ -204,28 +250,50 @@ $collection = (new Input\InputCollection())
 $usage = Cli\manpage( basename(__FILE__), $version,
 	'read write settings',
 	$collection, Colour::FG_GREEN, Colour::FG_WHITE,
-	[
-		'Examples' =>
-			 'cfg write myCEESV \'auth:projectId="218523"\''
-			 .PHP_EOL
-			 .'# writes local config: config/myCEESV.conf.php'
-			 .PHP_EOL
-			 .'cfg write myCEESV \'auth:projectId="218523"\' --directory-name=owner_xyz'
-			 .PHP_EOL
-			 .'# writes instance config: config/owner_xyz/myCEESV.conf.php'
-			 .PHP_EOL
-			 .'cfg show myCEESV auth:projectId --site=owner_xyz'
-			 .PHP_EOL
-			 .'# reads merged config including config/owner_xyz/myCEESV.conf.php'
-			 .PHP_EOL
-	]
+		[
+			'Examples' =>
+				'Basic usage:'
+				.PHP_EOL
+				 .'cfg show VeruA db:host'
+				 .PHP_EOL
+				 .'cfg write VeruA \'db:host="newHost"\''
+				 .PHP_EOL
+				 .PHP_EOL
+				.'Advance usage:'
+            	 .PHP_EOL
+				 .'cfg write prefix \'module:enabled=true\''
+				 .PHP_EOL
+				 .PHP_EOL
+				 .'#Site specific write:'
+				 .PHP_EOL
+				 .'cfg write prefix \'module:enabled=true\' --siteDir=owner_xyz'
+				 .PHP_EOL
+				 .PHP_EOL
+				 .'#Batch write from JSON file:'
+				 .PHP_EOL
+				 .'cfg write prefix --siteDir=owner_xyz -i /tmp/extension.json'
+				 .PHP_EOL
+				 .PHP_EOL
+				 .'#Batch write from JSON string:'
+				 .PHP_EOL
+				 .'cfg write prefix \'module={"enabled":true,"timeout":30,"label":"example"}\' --siteDir=owner_xyz'
+				 .PHP_EOL
+				 .PHP_EOL
+				 .'#Read merged value for a site:'
+				 .PHP_EOL
+				 .'cfg show prefix module:enabled --siteDir=owner_xyz'
+				 .PHP_EOL
+		]
 ).PHP_EOL;
 
 // Get the supplied input. Passing the collection will make the handler bind values
 // and validate the input according to our collection
-try {
+try
+{
 	$argv = Input\InputHandlerFactory::build('Argv', $collection);
-} catch (\Exception $ex) {
+}
+catch (\Exception $ex)
+{
 	echo $usage;
 
 	if (isset($argv[1])) {
@@ -247,27 +315,11 @@ if ($argv->find( 'help' ) || $argv->find('action') == 'help')
 
 
 $prefix = $argv->find('prefix');
-/* 
-echo $argv->find('action').PHP_EOL;
-echo ($prefix).PHP_EOL;
-echo $argv->find('setting')['key'].PHP_EOL;
-echo $argv->find('setting')['value'].PHP_EOL;
- */
-// var_dump($cfg);
+$verbose = (bool)$argv->find('verbose');
 $appPath = $argv->find('appPath');
 if (!$appPath) $appPath = getcwd().'/';
 $appPath = rtrim($appPath, '/').'/';
 
-/* $it = new RecursiveDirectoryIterator($appPath);
-
-foreach(new RecursiveIteratorIterator($it) as $file)
-{
-	$configDir = $file->getPath();
-	if ($file->isDir() && $file->getFilename() == '.' && basename($configDir) == 'config') {
-		echo "found config dir: $configDir\n";
-	}
-}
- */
 $mode = ($argv->find('mode') == '') ? null : $argv->find('mode');
 $cfg = (new Settings([], $mode))->appPath($appPath)->prefix($prefix);
 // pkgPath points to package defaults (e.g. <prefix>.default.conf.php)
@@ -275,70 +327,29 @@ if ($pkgPath = $argv->find('pkgPath')) $cfg->pkgPath(rtrim($pkgPath, '/').'/');
 
 $site = null;
 $siteFlag = 0x01;
-// Only one site selector may be provided to avoid ambiguous targets.
-$providedSiteOptions = [];
-foreach ($preparsedSiteOptions as $option) {
-	$providedSiteOptions[$option['name']][] = $option['value'] ?? '';
-}
-foreach (['site', 'directoryName'] as $optionName) {
-	$parsedValue = $argv->find($optionName);
-	if ($parsedValue !== null && $parsedValue !== '' && $parsedValue !== false) {
-		$providedSiteOptions[$optionName][] = $parsedValue;
-	}
+$site = $argv->find('siteDir');
+if ($site !== null && $site !== false)
+{
+		// Reuse util-settings site resolution: config/<site>/<prefix>.conf.php
+		$cfg->site($site);
+		verboseLog($verbose, "siteDir resolved to '$site'");
 }
 
-if (count($providedSiteOptions) > 1) {
-	fwrite(STDERR, 'Please use only one of --site or --directoryName (alias: --directory-name).'.PHP_EOL);
-	exit(1);
-}
-if (!empty($providedSiteOptions)) {
-	$optionName = array_key_first($providedSiteOptions);
-	$siteInput = trim((string)end($providedSiteOptions[$optionName]));
-
-    if ($optionName === 'directoryName') {
-        // Accept both "owner_xyz" and "config/owner_xyz" and normalize to site key.
-        if (str_starts_with($siteInput, $appPath.'config/')) {
-            $siteInput = substr($siteInput, strlen($appPath.'config/'));
-        } elseif (str_starts_with($siteInput, 'config/')) {
-            $siteInput = substr($siteInput, strlen('config/'));
-        }
-    }
-
-    $siteInput = trim($siteInput, '/');
-    if ($siteInput === '') {
-        fwrite(STDERR, "Option --$optionName is empty.".PHP_EOL);
-        exit(1);
-    }
-    // Block directory traversal and hidden-dot segments.
-    if (str_contains($siteInput, '..') || preg_match('~(^|/)\.(?:/|$)~', $siteInput)) {
-        fwrite(STDERR, "Invalid directory in --$optionName: '$siteInput'.".PHP_EOL);
-        exit(1);
-    }
-    // Allow only predictable path segments for instance directories.
-    foreach (explode('/', $siteInput) as $part) {
-        if ($part === '' || !preg_match('/^[A-Za-z0-9._-]+$/', $part)) {
-            fwrite(STDERR, "Invalid directory name segment '$part' in --$optionName.".PHP_EOL);
-            exit(1);
-        }
-    }
-
-    $site = $siteInput;
-    // Reuse util-settings site resolution: config/<site>/<prefix>.conf.php
-    $cfg->site($site);
-}
-
-try {
+try
+{
 	if (is_readable($cfg->buildFileName('default'))) {
 		$cfg->load();
 	}
 	elseif (is_readable($cfgFile = $cfg->buildFileName())) {
 		$cfg->load(require($cfgFile));
 	}
-} catch (\Throwable $e) {
+}
+catch (\Throwable $e)
+{
 	fwrite(STDERR, "Error: ".$e->getMessage().PHP_EOL);
 	exit(1);
 }
-//var_dump($cfg);
+verboseLog($verbose, 'config bootstrap loaded');
 
 $result = $cfg;
 $settings = $argv->find('setting') ?? $settings;
@@ -363,37 +374,57 @@ if ($result instanceof Settings) $result = $result->toArray();
 switch ($argv->find('action'))
 {
 case 'show':
+	verboseLog($verbose, "show action for prefix '$prefix'");
 	$out = (is_string($result)) ? $result : json_encode($result, JSON_PRETTY_PRINT);
 	echo $out.PHP_EOL;
 	break;
 	
 case 'write':
+	$inputPayload = $argv->find('in');
+	if (!$inputPayload && $settings['key'] === '')
+	{
+		fwrite(STDERR, 'Nothing to write: provide SETTING or --in.'.PHP_EOL);
+		exit(1);
+	}
 	$path = ($settings['key'] !== '') ? explode(':', $settings['key']) : [];
-
-	$setting2write = $settings['value'];
+	verboseLog($verbose, 'write source: '.($inputPayload ? '--in' : 'SETTING'));
+	
+	if ($inputPayload)
+	{
+		$setting2write = $inputPayload;
+	}
+	else
+	{
+		$setting2write = $settings['value'];
+	}
+	verboseLog($verbose, 'write path: '.json_encode($path));
 
 	while ( ! empty($path))
 	{
 		$setting2write = [array_pop($path) => $setting2write];
 	}
 
-	$writeType = ($site !== null) ? $siteFlag : null;
+    $writeType = ($site !== null && $site !== false) ? $siteFlag : null;
 	$file = $cfg->buildFileName($writeType);
+	verboseLog($verbose, "write target: $file");
 	if (is_readable($file))
 	{
 		$setting2write = array_replace_recursive(require($file), $setting2write);
 		copy($file, "$file.bak");
+		verboseLog($verbose, "existing config merged from: $file");
 	}
 
 	$targetDir = dirname($file);
-	if (!is_dir($targetDir) && !mkdir($targetDir, 0775, true) && !is_dir($targetDir)) {
+	if (!is_dir($targetDir) && !mkdir($targetDir, 0775, true) && !is_dir($targetDir))
+	{
 		fwrite(STDERR, "Can not create directory: $targetDir".PHP_EOL);
 		exit(1);
 	}
 
 	$writeCfg = $cfg->create($setting2write);
-//	var_dump($writeCfg->toArray());
-	try {
+	verboseLog($verbose, 'payload prepared for writer');
+	try
+	{
 		(new SettingsWriter($writeCfg, '', $writeType))->write();
 		echo "Written modified settings to: $file".PHP_EOL;
 	}
diff --git a/tests/CfgTest.php b/tests/CfgTest.php
index 79167ea..646bcb2 100644
--- a/tests/CfgTest.php
+++ b/tests/CfgTest.php
@@ -8,6 +8,7 @@ class CfgTest extends TestCase
 {
 	private string $tmpDir;
 
+	/* Lifecycle {{{ */
 	protected function setUp(): void
 	{
 		$this->tmpDir = rtrim(sys_get_temp_dir(), '/').'/util-settings-cfg-'.bin2hex(random_bytes(8));
@@ -15,8 +16,8 @@ class CfgTest extends TestCase
 		mkdir($this->tmpDir.'/config', 0775, true);
 
 		file_put_contents(
-			$this->tmpDir.'/config/myCEESV.default.conf.php',
-			"<?php return [\n\t'mode' => 'prod',\n\t'auth' => [\n\t\t'projectId' => '',\n\t\t'clientId' => '',\n\t],\n];\n"
+			$this->tmpDir.'/config/Extension.default.conf.php',
+			"<?php return [\n\t'mode' => 'prod',\n\t'module' => [\n\t\t'code' => '',\n\t\t'label' => '',\n\t\t'flags' => [\n\t\t\t'enabled' => false,\n\t\t],\n\t],\n\t'feature' => [\n\t\t'endpoint' => '',\n\t],\n];\n"
 		);
 	}
 
@@ -24,261 +25,390 @@ class CfgTest extends TestCase
 	{
 		$this->removeDir($this->tmpDir);
 	}
+	/* }}} */
 
+	/* Write Flow {{{ */
 	public function testWriteWithoutDirectoryNameUsesLocalConfigFile(): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
+		$result = $this->runWrite([
+			'module:code="X100"',
 		]);
 
-		$this->assertSame(0, $result['code'], $result['output']);
+		$this->assertCfgSuccess($result);
 
-		$localFile = $this->tmpDir.'/config/myCEESV.conf.php';
+		$localFile = $this->tmpDir.'/config/Extension.conf.php';
 		$this->assertFileExists($localFile);
 
 		$cfg = require $localFile;
-		$this->assertSame('218523', $cfg['auth']['projectId']);
+		$this->assertSame('X100', $cfg['module']['code']);
 	}
 
 	public function testWriteWithoutModeFallsBackToDefaultMode(): void
 	{
 		file_put_contents(
-			$this->tmpDir.'/config/myCEESV.default.conf.php',
-			"<?php return [\n\t'auth' => [\n\t\t'projectId' => '',\n\t],\n];\n"
+			$this->tmpDir.'/config/Extension.default.conf.php',
+			"<?php return [\n\t'module' => [\n\t\t'code' => '',\n\t],\n];\n"
 		);
 
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
+		$result = $this->runWrite([
+			'module:code="X100"',
 		]);
 
-		$this->assertSame(0, $result['code'], $result['output']);
-		$this->assertFileExists($this->tmpDir.'/config/myCEESV.conf.php');
+		$this->assertCfgSuccess($result);
+		$this->assertFileExists($this->tmpDir.'/config/Extension.conf.php');
 	}
 
-	public function testWriteWithDirectoryNameCreatesAndWritesSiteConfig(): void
+	public function testWriteWithInputFileWritesMultipleSettings(): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name',
-			'owner_xyz',
+		$inFile = $this->createJsonInputFile([
+			'module' => [
+				'code' => 'X100',
+				'label' => 'demo-module',
+			],
+			'feature' => [
+				'endpoint' => 'https://example.invalid/v1/resource',
+			],
 		]);
 
-		$this->assertSame(0, $result['code'], $result['output']);
+		$result = $this->runWrite([
+			'--siteDir=owner_xyz',
+			'-i',
+			$inFile,
+		]);
 
-		$siteFile = $this->tmpDir.'/config/owner_xyz/myCEESV.conf.php';
+		$this->assertCfgSuccess($result);
+		$cfg = $this->loadWrittenConfig('owner_xyz');
+		$this->assertSame('X100', $cfg['module']['code']);
+		$this->assertSame('demo-module', $cfg['module']['label']);
+		$this->assertSame('https://example.invalid/v1/resource', $cfg['feature']['endpoint']);
+	}
+
+	public function testWriteAcceptsJsonStringValueInSetting(): void
+	{
+		$result = $this->runWrite([
+			'module={"code":"X100","label":"demo-module"}',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgSuccess($result);
+		$cfg = $this->loadWrittenConfig('owner_xyz');
+		$this->assertSame('X100', $cfg['module']['code']);
+		$this->assertSame('demo-module', $cfg['module']['label']);
+	}
+
+	public function testWriteSupportsNestedPathWithColonNotation(): void
+	{
+		$result = $this->runWrite([
+			'module:flags:enabled=true',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgSuccess($result);
+		$cfg = $this->loadWrittenConfig('owner_xyz');
+		$this->assertTrue($cfg['module']['flags']['enabled']);
+	}
+
+	public function testWriteCoercesSimpleStringValueToJsonString(): void
+	{
+		$result = $this->runWrite([
+			'module:code=X100',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgSuccess($result);
+		$cfg = $this->loadWrittenConfig('owner_xyz');
+		$this->assertSame('X100', $cfg['module']['code']);
+	}
+
+	public function testWriteRejectsInvalidJsonStringValue(): void
+	{
+		$result = $this->runWrite([
+			'module={"code":',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgFailure($result, 'The value does not appear to be a valid JSON string.');
+	}
+
+	public function testWriteWithSiteDirCreatesAndWritesSiteConfig(): void
+	{
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgSuccess($result);
+
+		$siteFile = $this->tmpDir.'/config/owner_xyz/Extension.conf.php';
 		$this->assertFileExists($siteFile);
-		$this->assertFileDoesNotExist($this->tmpDir.'/config/myCEESV.conf.php');
+		$this->assertFileDoesNotExist($this->tmpDir.'/config/Extension.conf.php');
 
 		$cfg = require $siteFile;
-		$this->assertSame('218523', $cfg['auth']['projectId']);
+		$this->assertSame('X100', $cfg['module']['code']);
 	}
 
-	public function testWriteWithDirectoryNameMergesIntoExistingSiteConfig(): void
+	public function testWriteWithSiteDirMergesIntoExistingSiteConfig(): void
 	{
-		$firstWrite = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name',
-			'owner_xyz',
+		$firstWrite = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir=owner_xyz',
 		]);
-		$this->assertSame(0, $firstWrite['code'], $firstWrite['output']);
+		$this->assertCfgSuccess($firstWrite);
 
-		$secondWrite = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:clientId="service-9999-qual@myceesv.ch"',
-			'--directory-name',
-			'owner_xyz',
+		$secondWrite = $this->runWrite([
+			'module:label="demo-module"',
+			'--siteDir=owner_xyz',
 		]);
-		$this->assertSame(0, $secondWrite['code'], $secondWrite['output']);
+		$this->assertCfgSuccess($secondWrite);
 
-		$siteFile = $this->tmpDir.'/config/owner_xyz/myCEESV.conf.php';
-		$cfg = require $siteFile;
+		$cfg = $this->loadWrittenConfig('owner_xyz');
 
-		$this->assertSame('218523', $cfg['auth']['projectId']);
-		$this->assertSame('service-9999-qual@myceesv.ch', $cfg['auth']['clientId']);
+		$this->assertSame('X100', $cfg['module']['code']);
+		$this->assertSame('demo-module', $cfg['module']['label']);
 	}
 
-	public function testWriteWithDirectoryNameUsingConfigPrefixIsNormalized(): void
+	public function testWriteWithSiteDirUsingConfigPrefixIsNormalized(): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name=config/owner_xyz',
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir=config/owner_xyz',
 		]);
 
-		$this->assertSame(0, $result['code'], $result['output']);
-		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/myCEESV.conf.php');
-		$this->assertFileDoesNotExist($this->tmpDir.'/config/config/owner_xyz/myCEESV.conf.php');
+		$this->assertCfgSuccess($result);
+		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/Extension.conf.php');
+		$this->assertFileDoesNotExist($this->tmpDir.'/config/config/owner_xyz/Extension.conf.php');
 	}
 
-	public function testWriteWithSiteOptionWritesToSiteConfig(): void
+	public function testWriteWithSiteDirUsingAbsoluteConfigPrefixIsNormalized(): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--site=owner_xyz',
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir='.$this->tmpDir.'/config/owner_xyz',
 		]);
 
-		$this->assertSame(0, $result['code'], $result['output']);
-		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/myCEESV.conf.php');
+		$this->assertCfgSuccess($result);
+		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/Extension.conf.php');
 	}
 
-	public function testWriteWithDirectoryNameCamelCaseOptionWritesToSiteConfig(): void
+	public function testWriteWithNestedSiteDirWritesToNestedSiteConfig(): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directoryName=owner_xyz',
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir=owner_xyz/sub_a',
 		]);
 
-		$this->assertSame(0, $result['code'], $result['output']);
-		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/myCEESV.conf.php');
+		$this->assertCfgSuccess($result);
+		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/sub_a/Extension.conf.php');
+	}
+
+	public function testWriteWithSiteDirWritesToSiteConfig(): void
+	{
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgSuccess($result);
+		$this->assertFileExists($this->tmpDir.'/config/owner_xyz/Extension.conf.php');
 	}
 
 	public function testWriteToExistingSiteConfigCreatesBackup(): void
 	{
-		$firstWrite = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="first"',
-			'--directory-name=owner_xyz',
+		$firstWrite = $this->runWrite([
+			'module:code="first"',
+			'--siteDir=owner_xyz',
 		]);
-		$this->assertSame(0, $firstWrite['code'], $firstWrite['output']);
+		$this->assertCfgSuccess($firstWrite);
 
-		$secondWrite = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="second"',
-			'--directory-name=owner_xyz',
+		$secondWrite = $this->runWrite([
+			'module:code="second"',
+			'--siteDir=owner_xyz',
 		]);
-		$this->assertSame(0, $secondWrite['code'], $secondWrite['output']);
+		$this->assertCfgSuccess($secondWrite);
 
-		$siteFile = $this->tmpDir.'/config/owner_xyz/myCEESV.conf.php';
+		$siteFile = $this->tmpDir.'/config/owner_xyz/Extension.conf.php';
 		$backupFile = $siteFile.'.bak';
 		$this->assertFileExists($backupFile);
 
 		$current = require $siteFile;
 		$backup = require $backupFile;
-		$this->assertSame('second', $current['auth']['projectId']);
-		$this->assertSame('first', $backup['auth']['projectId']);
+		$this->assertSame('second', $current['module']['code']);
+		$this->assertSame('first', $backup['module']['code']);
 	}
+	/* }}} */
 
+	/* Show Flow {{{ */
 	public function testShowWithSiteReturnsSiteSpecificValue(): void
 	{
-		$this->runCfg([
+		$this->runWrite([
+			'module:code="X100"',
+			'--siteDir=owner_xyz',
+		]);
+
+		$show = $this->runShow([
+			'module:code',
+			'--siteDir=owner_xyz',
+		]);
+
+		$this->assertCfgSuccess($show);
+		$this->assertStringContainsString('X100', $show['output']);
+	}
+	/* }}} */
+
+	/* Validation {{{ */
+	public function testInvalidActionReturnsError(): void
+	{
+		$result = $this->runCfg([
+			'-a',
+			$this->tmpDir,
+			'delete',
+			'Extension',
+		]);
+
+		$this->assertCfgFailure($result, "'delete' not found");
+	}
+
+	public function testSiteDirRejectsEmptyValue(): void
+	{
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir=',
+		]);
+
+		$this->assertCfgFailure($result, 'a value is required for --siteDir');
+	}
+
+	/**
+	 * @dataProvider siteDirValidationDataProvider
+	 */
+	public function testSiteDirValidation(string $siteDir, string $expectedMessage): void
+	{
+		$result = $this->runWrite([
+			'module:code="X100"',
+			'--siteDir='.$siteDir,
+		]);
+
+		$this->assertCfgFailure($result, $expectedMessage);
+	}
+
+	/**
+	 * @dataProvider inputFileValidationDataProvider
+	 */
+	public function testInputFileValidation(?string $fileContents, string $pathSuffix, string $expectedMessage): void
+	{
+		$inFile = $this->tmpDir.'/'.$pathSuffix;
+		if ($fileContents !== null) {
+			file_put_contents($inFile, $fileContents);
+		}
+
+		$result = $this->runWrite([
+			'-i',
+			$inFile,
+		]);
+
+		$this->assertCfgFailure($result, $expectedMessage);
+	}
+
+	/**
+	 * @dataProvider writePayloadSourceValidationDataProvider
+	 */
+	public function testWritePayloadSourceValidation(array $extraArgs, string $expectedMessage): void
+	{
+		$inFile = $this->createJsonInputFile(['module' => ['code' => 'X100']]);
+
+		$args = array_merge(
+			[
+				'-a',
+				$this->tmpDir,
+				'write',
+				'Extension',
+			],
+			array_map(
+				fn (string $arg): string => $arg === '__INPUT_FILE__' ? $inFile : $arg,
+				$extraArgs
+			)
+		);
+
+		$result = $this->runCfg($args);
+
+		$this->assertCfgFailure($result, $expectedMessage);
+	}
+
+	public function siteDirValidationDataProvider(): array
+	{
+		return [
+			'traversal' => ['../owner_xyz', 'Invalid directory in --siteDir'],
+			'invalid segment' => ['owner xyz', "Invalid directory name segment 'owner xyz' in --siteDir."],
+			'hidden dot segment' => ['owner_xyz/./secret', "Invalid directory in --siteDir: 'owner_xyz/./secret'."],
+			'config root only' => ['config/', 'Option --siteDir is empty.'],
+		];
+	}
+
+	public function inputFileValidationDataProvider(): array
+	{
+		return [
+			'missing file' => [null, 'missing.json', 'Input file is not readable'],
+			'invalid json' => ['{"module":', 'invalid.json', 'Input JSON is invalid'],
+			'scalar json' => ['true', 'scalar.json', 'Input JSON must decode to an object/array'],
+		];
+	}
+
+	public function writePayloadSourceValidationDataProvider(): array
+	{
+		return [
+			'missing payload source' => [[], 'Nothing to write: provide SETTING or --in.'],
+			'both payload sources' => [['module:code="x"', '-i', '__INPUT_FILE__'], 'Please use either SETTING or --in, not both.'],
+		];
+	}
+	/* }}} */
+
+	/* Helpers {{{ */
+	private function runWrite(array $args): array
+	{
+		return $this->runCfg(array_merge([
 			'-a',
 			$this->tmpDir,
 			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name=owner_xyz',
-		]);
+			'Extension',
+		], $args));
+	}
 
-		$show = $this->runCfg([
+	private function runShow(array $args): array
+	{
+		return $this->runCfg(array_merge([
 			'-a',
 			$this->tmpDir,
 			'show',
-			'myCEESV',
-			'auth:projectId',
-			'--site=owner_xyz',
-		]);
-
-		$this->assertSame(0, $show['code'], $show['output']);
-		$this->assertStringContainsString('218523', $show['output']);
+			'Extension',
+		], $args));
 	}
 
-	public function testDirectoryNameRejectsTraversal(): void
+	private function createJsonInputFile(array $contents, string $name = 'extension-in.json'): string
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name=../owner_xyz',
-		]);
+		$path = $this->tmpDir.'/'.$name;
+		file_put_contents($path, json_encode($contents, JSON_PRETTY_PRINT));
 
-		$this->assertSame(1, $result['code']);
-		$this->assertStringContainsString('Invalid directory in --directoryName', $result['output']);
+		return $path;
 	}
 
-	public function testDirectoryNameRejectsInvalidSegment(): void
+	private function loadWrittenConfig(?string $siteDir = null): array
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name=owner xyz',
-		]);
+		$path = $siteDir === null
+			? $this->tmpDir.'/config/Extension.conf.php'
+			: $this->tmpDir.'/config/'.$siteDir.'/Extension.conf.php';
 
-		$this->assertSame(1, $result['code']);
-		$this->assertStringContainsString("Invalid directory name segment 'owner xyz' in --directoryName.", $result['output']);
+		return require $path;
 	}
 
-	public function testDirectoryNameRejectsEmptyValue(): void
+	private function assertCfgSuccess(array $result): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--directory-name=',
-		]);
-
-		$this->assertSame(1, $result['code']);
-		$this->assertStringContainsString('Option --directoryName is empty.', $result['output']);
+		$this->assertSame(0, $result['code'], $result['output']);
 	}
 
-	public function testUsingSiteAndDirectoryNameTogetherReturnsError(): void
+	private function assertCfgFailure(array $result, string $message): void
 	{
-		$result = $this->runCfg([
-			'-a',
-			$this->tmpDir,
-			'write',
-			'myCEESV',
-			'auth:projectId="218523"',
-			'--site',
-			'owner_xyz',
-			'--directory-name',
-			'owner_xyz',
-		]);
-
-		$this->assertSame(1, $result['code']);
-		$this->assertStringContainsString('Please use only one of --site or --directoryName (alias: --directory-name).', $result['output']);
+		$this->assertSame(1, $result['code'], $result['output']);
+		$this->assertStringContainsString($message, $result['output']);
 	}
 
 	private function runCfg(array $args): array
@@ -323,4 +453,5 @@ class CfgTest extends TestCase
 
 		rmdir($dir);
 	}
+	/* }}} */
 }
diff --git a/tests/SettingsTest.php b/tests/SettingsTest.php
index ae70ef7..09f311c 100644
--- a/tests/SettingsTest.php
+++ b/tests/SettingsTest.php
@@ -224,17 +224,17 @@ class SettingsTest extends TestCase
 	public function testBuildFileNameWithPrefixAndSite(): void
 	{
 		$cfg = new Settings();
-		$cfg->appPath('./')->prefix('myCEESV')->site('owner_xyz');
+		$cfg->appPath('./')->prefix('Extension')->site('owner_xyz');
 
-		$this->assertEquals('./config/owner_xyz/myCEESV.conf.php', $cfg->buildFileName(0x01));
+		$this->assertEquals('./config/owner_xyz/Extension.conf.php', $cfg->buildFileName(0x01));
 	}
 
 	public function testBuildFileNameWithPrefixAndNestedSite(): void
 	{
 		$cfg = new Settings();
-		$cfg->appPath('./')->prefix('myCEESV')->site('owner_xyz/sub_a');
+		$cfg->appPath('./')->prefix('Extension')->site('owner_xyz/sub_a');
 
-		$this->assertEquals('./config/owner_xyz/sub_a/myCEESV.conf.php', $cfg->buildFileName(0x01));
+		$this->assertEquals('./config/owner_xyz/sub_a/Extension.conf.php', $cfg->buildFileName(0x01));
 	}
 	
 	public function fileNameData()