diff --git a/.aiignore b/.aiignore
index 38f7c569..df178378 100644
--- a/.aiignore
+++ b/.aiignore
@@ -4,3 +4,6 @@
 # cache and debug
 var/cache/
 var/xdebug-profile/
+
+# secret
+.env
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index 0fd60494..b1b1596c 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -14,8 +14,9 @@ Type of Change
 Please delete options that are not relevant:
 
 - [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] Improvements (non-breaking changes such as refactoring, performance optimization, etc.)
 - [ ] New feature (non-breaking change which adds functionality)
-- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] Breaking change (bug fix, new feature, dependency upgrade, etc.)
 - [ ] Documentation update
 - [ ] Other (please specify):
 
diff --git a/AGENTS.md b/AGENTS.md
index 4c43d9b8..77692075 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -43,20 +43,20 @@ Directory Structure
 
 ### Examples
 
-- `examples`: samples how to use `DefinitionGeneratorFacade` and `TransferGeneratorFacade`
+- `examples`: samples on how to use `DefinitionGeneratorFacade` and `TransferGeneratorFacade`
 
 ### Source
 
 - `src`: code source
 - `src/Command`: Symfony console commands to generate definition and transfer object files
 - `src/DefinitionGenerator`: definition generator module
-- `src/Dependency`: wrapper over 3-part dependencies
+- `src/Dependency`: wrapper over third-party dependencies
 - `src/Generated`: directory where generated transfer objects are saved
   * should not contain any custom-written code
-  * each transfer object generator run will overwrite all the files in the directory
+  * each transfer object generator run overwrites all the files in the directory
   * can be used across modules
-- `src/Generated/_tmp`: temporary directory includes newly generated transfer objects before they are finally moved to the `src/Generated`
-  * in case of an unexpected error, the directory might not be deleted
+- `src/Generated/_tmp`: temporary directory including newly generated transfer objects before they are finally moved to the `src/Generated`
+  * in case of an unexpected error, the directory might not be deleted.
 - `src/Shared`: contains code shared across modules
   * can be used across modules
 - `src/Transfer`: transfer object module
@@ -100,7 +100,7 @@ Code Style
 
 ### Tests
 
-- tests classes should be a `final`
+- test classes should be `final`
 - tests should have at least one test group
 
 Module Structure
@@ -108,12 +108,12 @@ Module Structure
 
 #### Facade
 
-- each module should have a facade class with an interface
-- the facade class and interface name should include the module name with `Facade` suffix
-- the facade is used for communication between modules
-- the facade used factories
-- the facade should not include any business logic
-- the facade `public` methods should have specification doc-block
+- each module should have a facade class with an interface.
+- the facade class and interface name should include the module name with `Facade` suffix.
+- the facade is used for communication between modules.
+- the facade uses factories.
+- the facade should not include any business logic.
+- the facade `public` methods should have a specification doc-block.
 
 ### Factory
 
@@ -129,26 +129,34 @@ Module Structure
 Unit and Integration Tests
 --------------------------
 
-- tests should follow a similar structure to the existing ones
-- separate test implementation by comment sections: "Arrange", "Act", "Assert" (optionally with "Expect")
-- use `setUp` method to initialize the tested object's stubs and mocks
-- use `PHPUnit` attributes
-- use [PHP generator](https://www.php.net/manual/en/class.generator.php) for the data providers
+- tests should follow a similar structure to the existing ones.
+- separate test implementation by comment sections: "Arrange", "Act", "Assert" (optionally with "Expect").
+- use `setUp` method to initialize the tested object's stubs and mocks.
+- use `PHPUnit` attributes.
+- use [PHP generator](https://www.php.net/manual/en/class.generator.php) for the data providers.
+
+How To Install Project
+----------------------
+
+The project is installed by running the following command:
+```console
+docker/sdk install
+```
 
 How To Build/Start/Stop Docker Environment
 -------------------------------------------
 
-Docker Environment can be built by running the following command:
+Docker Environment is built by running the following command:
 ```console
 docker/sdk build
 ```
 
-Docker Environment can be started by running the following command:
+Docker Environment is started by running the following command:
 ```console
 docker/sdk start
 ```
 
-Docker Environment can be stopped by running the following command:
+Docker Environment is stopped by running the following command:
 ```console
 docker/sdk stop
 ```
@@ -156,7 +164,7 @@ docker/sdk stop
 How to Run PHP Script
 ---------------------
 
-The PHP script can be run by command:
+The PHP script runs by command:
 ```console
 docker/sdk cli [path-to-script]
 ```
@@ -169,7 +177,7 @@ docker/sdk cli ./examples/try-transfer-generator.php
 How to Generate Internal Transfer Objects
 -----------------------------------------
 
-The all project transfer objects (generator's, examples, tests) can be generated with the following command:
+All project transfer objects (generator's, examples, tests) can be generated with the following command:
 ```console
 docker/sdk to-generate-bulk
 ```
@@ -182,29 +190,29 @@ docker/sdk to-generate
 How to Generate Transfer Objects By Configuration File
 ------------------------------------------------------
 
-Transfer Objects can be generated by configuration file path, relative from the project's root, by running the following command:
+Transfer objects can be generated by a configuration file path, relative from the project's root, by running the following command:
 ```console
 docker/sdk to-generate [path-to-configuration-file]
 ```
 
-How To Run PHPUnit Tests
+How to Run PHPUnit Tests
 ------------------------
 
-### All Tests
+### How to Run All Tests
 
 All tests can be run with the following command:
 ```console
 docker/sdk phpunit
 ```
 
-### Specific Group
+### How to Run Test Group
 
 A test group can be run with the following command:
 ```console
 docker/sdk phpunit-group <group>
 ```
 
-### Specific Test Case
+### How to Run Test Case
 
 A test case can be run with the following command:
 ```console
@@ -217,26 +225,54 @@ can be run with the following command:
 docker/sdk phpunit 'Picamator\\Tests\\Unit\\TransferObject\\Command\\Helper\\InputNormalizerTest'
 ```
 
-How To Run PHPStan
+How to Run PHPStan
 ------------------
 
-PHPStan can be run with the following command:
+For all project's files, PHPStan can be run with the following command:
 ```console
 docker/sdk phpstan
 ```
 
-How To Run PHP CodeSniffer
+For the specific file:
+```console
+docker/sdk phpstan <file-path>
+```
+
+How to Run PHP CodeSniffer
 --------------------------
 
-PHP CodeSniffer can be run with the following command:
+For all project's files, PHP CodeSniffer can be run with the following command:
 ```console
 docker/sdk phpcs
 ```
 
-How To Run Composer
+For the specific file:
+```console
+docker/sdk phpcs <file-path>
+```
+
+How to Run PHP Code Beautifier and Fixer
+----------------------------------------
+
+For all project's files, PHP Code Beautifier and Fixer can be run with the following command:
+```console
+docker/sdk phpcbf
+```
+
+For the specific file:
+```console
+docker/sdk phpcbf <file-path>
+```
+
+How to Run Composer
 -------------------
 
-PHPStan can be run with the following command:
+Composer can be run with the following command:
 ```console
 docker/sdk composer
 ```
+
+The command supports multiple arguments, for example:
+```console
+docker/sdk composer install
+```
diff --git a/docker/sdk b/docker/sdk
index 882a8978..826798dd 100755
--- a/docker/sdk
+++ b/docker/sdk
@@ -12,7 +12,7 @@ function wrap_in_yellow() {
 
 # function to print a command/option with its description
 function print_command() {
-  printf "  %-35s %s\n" "$(wrap_in_yellow "$1")" "$2"
+  printf "  %-40s %s\n" "$(wrap_in_yellow "$1")" "$2"
 }
 
 # function to print an example with its description
@@ -30,7 +30,7 @@ function show_usage() {
   echo
   echo "Options:"
   print_command "-x" "Enable Xdebug (debug, coverage)"
-  print_command "-p" "Enable Xdebug (profiler)"
+  print_command "-p" "Enable Xdebug (profile)"
   echo
   echo "Commands:"
   print_command "install" "Install development environment"
@@ -39,20 +39,20 @@ function show_usage() {
   print_command "stop" "Stop Docker containers"
   print_command "cli [script]" "Open container shell or execute PHP script"
   print_command "composer <cmd>" "Run composer command"
-  print_command "phpstan" "Run PHPStan"
+  print_command "phpstan [file]" "Run PHPStan for all project's files or for specified one"
   print_command "phpunit [filter]" "Run PHPUnit tests"
-  print_command "phpunit-group <g>" "Run PHPUnit tests by group"
-  print_command "phpcs" "Run PHP CodeSniffer"
-  print_command "phpcbf" "Run PHP Code Beautifier and Fixer"
+  print_command "phpunit-group [group]" "Run PHPUnit tests by group"
+  print_command "phpcs [file]" "Run PHP CodeSniffer for all project's files or for specified one"
+  print_command "phpcbf [file]" "Run PHP Code Beautifier and Fixer for all project's files or for specified one"
   print_command "hook-install" "Install CaptainHook"
-  print_command "hook <cmd>" "Run CaptainHook command"
-  print_command "to-generate [c]" "Generate transfer objects"
-  print_command "to-generate-bulk [b]" "Generate bulk transfer objects"
-  print_command "df-generate" "Generate definitions"
+  print_command "hook [cmd]" "Run CaptainHook command"
+  print_command "to-generate [config]" "Generate Transfer Objects from YML definitions"
+  print_command "to-generate-bulk [bulk]" "Generate Transfer Objects in bulk from a config list"
+  print_command "df-generate" "Generate definition files from JSON blueprints"
   echo
   echo "Examples:"
   print_example "$0 -x start" "Start containers (Xdebug: debug, coverage)"
-  print_example "$0 -p start" "Start containers (Xdebug: profiler)"
+  print_example "$0 -p start" "Start containers (Xdebug: profile)"
   print_example "$0 composer install" "Run composer install inside container"
 }
 
@@ -91,7 +91,7 @@ case $1 in
     if [ "$XDEBUG_MODE" == "" ]; then
       docker compose up -d --remove-orphans
     else
-      XDEBUG_MODE={$XDEBUG_MODE} docker compose up -d --remove-orphans
+      XDEBUG_MODE=${XDEBUG_MODE} docker compose up -d --remove-orphans
     fi
     ;;
   stop)
@@ -108,7 +108,7 @@ case $1 in
     $DOCKER_EXEC composer "${@:2}"
     ;;
   phpstan)
-    $DOCKER_EXEC composer phpstan
+    $DOCKER_EXEC composer phpstan "${@:2}"
     ;;
   phpunit)
     if [ -n "$2" ]; then
@@ -118,13 +118,13 @@ case $1 in
     fi
     ;;
   phpunit-group)
-    $DOCKER_EXEC composer phpunit-group "$2"
+    $DOCKER_EXEC composer phpunit-group "${@:2}"
     ;;
   phpcs)
-    $DOCKER_EXEC composer phpcs
+    $DOCKER_EXEC composer phpcs "${@:2}"
     ;;
   phpcbf)
-    $DOCKER_EXEC composer phpcbf
+    $DOCKER_EXEC composer phpcbf "${@:2}"
     ;;
   hook-install)
     $DOCKER_EXEC composer captainhook install --only-enabled --run-mode=docker --run-exec="docker exec -i $DOCKER_CONTAINER_NAME"
diff --git a/src/Transfer/AbstractTransfer.php b/src/Transfer/AbstractTransfer.php
index 4250425a..1b21b514 100644
--- a/src/Transfer/AbstractTransfer.php
+++ b/src/Transfer/AbstractTransfer.php
@@ -13,7 +13,10 @@
  */
 abstract class AbstractTransfer implements TransferInterface
 {
-    use AttributeTrait;
+    use AttributeTrait {
+        getInitiatorAttribute as private;
+        getTransformerAttribute as private;
+    }
 
     /**
      * @var int<0, max>
@@ -115,6 +118,10 @@ final public function toArray(): array
             $index = $metaData[$propertyName];
             $value = $this->_data[$index];
 
+            if ($value === null) {
+                continue;
+            }
+
             $data[$propertyName] = $this->getTransformerAttribute($constantName)->toArray($value);
             unset($metaData[$propertyName]);
         }
diff --git a/src/Transfer/Attribute/AttributeTrait.php b/src/Transfer/Attribute/AttributeTrait.php
index 6239f3c1..57ecb11b 100644
--- a/src/Transfer/Attribute/AttributeTrait.php
+++ b/src/Transfer/Attribute/AttributeTrait.php
@@ -17,7 +17,7 @@ trait AttributeTrait
      */
     private static array $_attributeCache = [];
 
-    final protected function getInitiatorAttribute(string $constantName): InitiatorAttributeInterface
+    protected function getInitiatorAttribute(string $constantName): InitiatorAttributeInterface
     {
         /** @var \ReflectionAttribute<InitiatorAttributeInterface> $reflectionAttribute */
         $reflectionAttribute = $this->getConstantReflection(
@@ -34,7 +34,7 @@ final protected function getInitiatorAttribute(string $constantName): InitiatorA
     /**
      * @throws \Picamator\TransferObject\Transfer\Exception\AttributeTransferException
      */
-    final protected function getTransformerAttribute(string $constantName): TransformerAttributeInterface
+    protected function getTransformerAttribute(string $constantName): TransformerAttributeInterface
     {
         /** @var \ReflectionAttribute<TransformerAttributeInterface> $reflectionAttribute */
         $reflectionAttribute = $this->getConstantReflection(
diff --git a/src/Transfer/Attribute/Transformer/DateTimeTransformerAttribute.php b/src/Transfer/Attribute/Transformer/DateTimeTransformerAttribute.php
index 9795a9ee..626cf846 100644
--- a/src/Transfer/Attribute/Transformer/DateTimeTransformerAttribute.php
+++ b/src/Transfer/Attribute/Transformer/DateTimeTransformerAttribute.php
@@ -45,10 +45,10 @@ public function fromArray(mixed $data): DateTimeInterface
     }
 
     /**
-     * @param DateTimeInterface|null $data
+     * @param DateTimeInterface $data
      */
-    public function toArray(mixed $data): ?string
+    public function toArray(mixed $data): string
     {
-        return $data?->format(self::DATE_TIME_FORMAT);
+        return $data->format(self::DATE_TIME_FORMAT);
     }
 }
diff --git a/src/Transfer/Attribute/Transformer/EnumTransformerAttribute.php b/src/Transfer/Attribute/Transformer/EnumTransformerAttribute.php
index 8a01d1c0..c444bde9 100644
--- a/src/Transfer/Attribute/Transformer/EnumTransformerAttribute.php
+++ b/src/Transfer/Attribute/Transformer/EnumTransformerAttribute.php
@@ -35,11 +35,11 @@ public function fromArray(mixed $data): ?BackedEnum
     }
 
     /**
-     * @param BackedEnum|null $data
+     * @param BackedEnum $data
      */
-    public function toArray(mixed $data): string|int|null
+    public function toArray(mixed $data): string|int
     {
-        return $data?->value;
+        return $data->value;
     }
 
     /**
diff --git a/src/Transfer/Attribute/Transformer/NumberTransformerAttribute.php b/src/Transfer/Attribute/Transformer/NumberTransformerAttribute.php
index 18ae171b..5e216a81 100644
--- a/src/Transfer/Attribute/Transformer/NumberTransformerAttribute.php
+++ b/src/Transfer/Attribute/Transformer/NumberTransformerAttribute.php
@@ -40,10 +40,10 @@ public function fromArray(mixed $data): Number
     }
 
     /**
-     * @param \BcMath\Number|null $data
+     * @param \BcMath\Number $data
      */
-    public function toArray(mixed $data): ?string
+    public function toArray(mixed $data): string
     {
-        return $data?->__toString();
+        return $data->__toString();
     }
 }
diff --git a/src/Transfer/Attribute/Transformer/TransferTransformerAttribute.php b/src/Transfer/Attribute/Transformer/TransferTransformerAttribute.php
index 4acb6797..c29f13d1 100644
--- a/src/Transfer/Attribute/Transformer/TransferTransformerAttribute.php
+++ b/src/Transfer/Attribute/Transformer/TransferTransformerAttribute.php
@@ -28,12 +28,12 @@ public function fromArray(mixed $data): TransferInterface
     }
 
     /**
-     * @param \Picamator\TransferObject\Transfer\TransferInterface|null $data
+     * @param \Picamator\TransferObject\Transfer\TransferInterface $data
      *
-     * @return array<int|string,mixed>|null
+     * @return array<int|string,mixed>
      */
-    public function toArray(mixed $data): ?array
+    public function toArray(mixed $data): array
     {
-        return $data?->toArray();
+        return $data->toArray();
     }
 }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/AbstractPropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/AbstractPropertyExpander.php
index 9481cec4..dd1e8e15 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/AbstractPropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/AbstractPropertyExpander.php
@@ -8,12 +8,31 @@
 
 abstract class AbstractPropertyExpander implements PropertyExpanderInterface
 {
-    use PropertyExpanderTrait;
+    private ?PropertyExpanderInterface $nextExpander = null;
+
+    public function setNextExpander(PropertyExpanderInterface $expander): PropertyExpanderInterface
+    {
+        $this->nextExpander = $expander;
+
+        return $expander;
+    }
+
+    public function expandPropertyTransfer(array $propertyType, DefinitionPropertyTransfer $propertyTransfer): void
+    {
+        $matchedType = $this->matchType($propertyType);
+        if ($matchedType !== null) {
+            $this->handleExpander($matchedType, $propertyTransfer);
+        }
+
+        $this->nextExpander?->expandPropertyTransfer($propertyType, $propertyTransfer);
+    }
 
     /**
      * @param array<string,string|array<int,string>|null> $propertyType
+     *
+     * @return string|array<string, string|array<int,string>|null>|null
      */
-    abstract protected function matchType(array $propertyType): ?string;
+    abstract protected function matchType(array $propertyType): string|array|null;
 
-    abstract protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void;
+    abstract protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void;
 }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/AttributesPropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/AttributesPropertyExpander.php
index 1cbc30c6..665acd49 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/AttributesPropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/AttributesPropertyExpander.php
@@ -8,10 +8,8 @@
 use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
 use Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander\Builder\NamespaceBuilderInterface;
 
-final class AttributesPropertyExpander implements PropertyExpanderInterface
+final class AttributesPropertyExpander extends AbstractPropertyExpander implements PropertyExpanderInterface
 {
-    use PropertyExpanderTrait;
-
     private const string ATTRIBUTES_KEY = 'attributes';
 
     private const string ATTRIBUTES_REGEX = '#^(?<namespace>[^()]+)\s*(?<arguments>.*)$#';
@@ -37,7 +35,7 @@ protected function matchType(array $propertyType): ?array
     /**
      * @param array<int,string> $matchedType
      */
-    protected function handleExpander(array $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         foreach ($matchedType as $attribute) {
             $attributeTransfer = $this->getAttributeTransfer($attribute);
diff --git a/src/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilder.php b/src/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilder.php
index 6cc5e07a..99c58932 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilder.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilder.php
@@ -8,8 +8,11 @@
 
 readonly class AttributesNamespaceBuilder implements NamespaceBuilderInterface
 {
-    protected const array SHORTCUT_MAP = [
-        'sf-assert:' => 'Symfony\Component\Validator\Constraints\\',
+    /**
+     * @var array<string, string>
+     */
+    protected const array SHORTCUT_PATTERN_MAP = [
+        '#^(?<shortcut>sf-assert:\s*)(?<className>.+)$#' => 'Symfony\Component\Validator\Constraints\\',
     ];
 
     public function __construct(
@@ -24,17 +27,14 @@ public function createNamespaceTransfer(string $namespace): DefinitionNamespaceT
         return $this->namespaceBuilder->createNamespaceTransfer($namespace);
     }
 
-    public static function renderShortcut(string $namespace): string
+    private function renderShortcut(string $namespace): string
     {
-        foreach (static::SHORTCUT_MAP as $shortcut => $fullName) {
-            if (!str_starts_with($namespace, $shortcut)) {
+        foreach (static::SHORTCUT_PATTERN_MAP as $pattern => $replacement) {
+            if (preg_match($pattern, $namespace, $matches) !== 1) {
                 continue;
             }
 
-            /** @var string $fullName */
-            $namespace = str_replace($shortcut, $fullName, $namespace);
-
-            return str_replace(' ', '', $namespace);
+            return $replacement . $matches['className'];
         }
 
         return $namespace;
diff --git a/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php
index 0ff456e9..fa26276b 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php
@@ -24,7 +24,10 @@ protected function matchType(array $propertyType): ?string
         return $matchType;
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         $propertyTransfer->collectionType = $this->typeBuilder->createPrefixTypeTransfer($matchedType);
         $propertyTransfer->isRequired = true;
diff --git a/src/TransferGenerator/Definition/Parser/Expander/DateTimeTypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/DateTimeTypePropertyExpander.php
index b9135216..7e43025a 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/DateTimeTypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/DateTimeTypePropertyExpander.php
@@ -24,7 +24,10 @@ protected function matchType(array $propertyType): ?string
         return $matchType;
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         $propertyTransfer->dateTimeType = $this->typeBuilder->createTypeTransfer($matchedType);
     }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/EnumTypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/EnumTypePropertyExpander.php
index e07a7a2d..b8177501 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/EnumTypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/EnumTypePropertyExpander.php
@@ -24,7 +24,10 @@ protected function matchType(array $propertyType): ?string
         return $matchType;
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         $propertyTransfer->enumType = $this->typeBuilder->createTypeTransfer($matchedType);
     }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/NumberTypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/NumberTypePropertyExpander.php
index d5dc4ee8..4140a4d6 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/NumberTypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/NumberTypePropertyExpander.php
@@ -24,7 +24,10 @@ protected function matchType(array $propertyType): ?string
         return $matchType;
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         $propertyTransfer->numberType = $this->typeBuilder->createTypeTransfer($matchedType);
     }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/PropertyExpanderTrait.php b/src/TransferGenerator/Definition/Parser/Expander/PropertyExpanderTrait.php
deleted file mode 100644
index fb92cadb..00000000
--- a/src/TransferGenerator/Definition/Parser/Expander/PropertyExpanderTrait.php
+++ /dev/null
@@ -1,29 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander;
-
-use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
-
-trait PropertyExpanderTrait
-{
-    private ?PropertyExpanderInterface $nextExpander = null;
-
-    public function setNextExpander(PropertyExpanderInterface $expander): PropertyExpanderInterface
-    {
-        $this->nextExpander = $expander;
-
-        return $expander;
-    }
-
-    public function expandPropertyTransfer(array $propertyType, DefinitionPropertyTransfer $propertyTransfer): void
-    {
-        $matchedType = $this->matchType($propertyType);
-        if ($matchedType !== null) {
-            $this->handleExpander($matchedType, $propertyTransfer);
-        }
-
-        $this->nextExpander?->expandPropertyTransfer($propertyType, $propertyTransfer);
-    }
-}
diff --git a/src/TransferGenerator/Definition/Parser/Expander/ProtectedPropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/ProtectedPropertyExpander.php
index 098c905c..045c4a04 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/ProtectedPropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/ProtectedPropertyExpander.php
@@ -15,7 +15,10 @@ protected function matchType(array $propertyType): string
         return array_key_exists(self::PROTECTED_KEY, $propertyType) ? '1' : '0';
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         $propertyTransfer->isProtected = $matchedType === '1';
     }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/RequiredPropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/RequiredPropertyExpander.php
index 2334b9f6..ef7655a4 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/RequiredPropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/RequiredPropertyExpander.php
@@ -15,7 +15,10 @@ protected function matchType(array $propertyType): string
         return array_key_exists(self::REQUIRED_KEY, $propertyType) ? '1' : '0';
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         if (!$this->isNullableAllowed($propertyTransfer)) {
             $propertyTransfer->isRequired = true;
@@ -33,11 +36,6 @@ private function isNullableAllowed(DefinitionPropertyTransfer $propertyTransfer)
             return false;
         }
 
-        // phpcs:disable SlevomatCodingStandard.ControlStructures.UselessIfConditionWithReturn
-        if ($propertyTransfer->collectionType !== null) {
-            return false;
-        }
-
-        return true;
+        return $propertyTransfer->collectionType === null;
     }
 }
diff --git a/src/TransferGenerator/Definition/Parser/Expander/TypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/TypePropertyExpander.php
index 90d94817..17b8f54f 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/TypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/TypePropertyExpander.php
@@ -29,7 +29,10 @@ protected function matchType(array $propertyType): ?string
         return $matchType;
     }
 
-    protected function handleExpander(string $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
+    /**
+     * @param string $matchedType
+     */
+    protected function handleExpander(mixed $matchedType, DefinitionPropertyTransfer $propertyTransfer): void
     {
         $builtInTypeTransfer = $this->getBuiltInTypeTransfer($matchedType);
         if ($builtInTypeTransfer !== null) {
diff --git a/src/TransferGenerator/Definition/Reader/DefinitionReader.php b/src/TransferGenerator/Definition/Reader/DefinitionReader.php
index 6e50852c..b0142957 100644
--- a/src/TransferGenerator/Definition/Reader/DefinitionReader.php
+++ b/src/TransferGenerator/Definition/Reader/DefinitionReader.php
@@ -38,8 +38,9 @@ public function getDefinitions(): Generator
 
                 yield from $contentGenerator;
 
-                /** @phpstan-ignore assignOp.invalid */
-                $count += $contentGenerator->getReturn();
+                /** @var int $contentGeneratorReturn */
+                $contentGeneratorReturn = $contentGenerator->getReturn();
+                $count += $contentGeneratorReturn;
             }
         } catch (FinderException | TransferGeneratorDefinitionException | YmlParserException $e) {
             yield $this->createErrorDefinitionTransfer($e, fileName: $fileName ?? '');
diff --git a/src/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpander.php b/src/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpander.php
index 68b07dd2..b4d3842f 100644
--- a/src/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpander.php
+++ b/src/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpander.php
@@ -9,9 +9,9 @@
 
 final class MetaConstantsTemplateExpander extends AbstractTemplateExpander
 {
-    private const string META_CONSTANT_SNAKE_CASE_REGEX = '#(?<!^)[A-Z]#';
+    private const string META_CONSTANT_SNAKE_CASE_REGEX = '#(?<!^)(?<![A-Z])[A-Z]|(?<!^)[A-Z](?=[a-z])#';
 
-    private const string META_CONSTANT_ONLY_UPPER_CASE_REGEX = '#^[A-Z_]+$#';
+    private const string META_CONSTANT_ONLY_UPPER_CASE_REGEX = '#^[A-Z\d_]+$#';
 
     /**
      * phpcs:disable SlevomatCodingStandard.Functions.UnusedParameter
diff --git a/src/TransferGenerator/Generator/Render/Template/Helper/IterableHelperTrait.php b/src/TransferGenerator/Generator/Render/Template/Helper/IterableHelperTrait.php
index ffb19da4..e21712a5 100644
--- a/src/TransferGenerator/Generator/Render/Template/Helper/IterableHelperTrait.php
+++ b/src/TransferGenerator/Generator/Render/Template/Helper/IterableHelperTrait.php
@@ -11,11 +11,11 @@ trait IterableHelperTrait
      */
     final protected function renderIterable(iterable $iterable, string $template): string
     {
-        $rendered = '';
+        $renderedIterable = '';
         foreach ($iterable as $item) {
-            $rendered .= sprintf($template, $item);
+            $renderedIterable .= sprintf($template, $item);
         }
 
-        return rtrim($rendered, PHP_EOL);
+        return rtrim($renderedIterable, PHP_EOL);
     }
 }
diff --git a/src/TransferGenerator/Generator/Render/Template/Helper/TemplateHelper.php b/src/TransferGenerator/Generator/Render/Template/Helper/TemplateHelper.php
index d8be83a5..00f9de05 100644
--- a/src/TransferGenerator/Generator/Render/Template/Helper/TemplateHelper.php
+++ b/src/TransferGenerator/Generator/Render/Template/Helper/TemplateHelper.php
@@ -36,43 +36,41 @@ public function renderImports(): string
 
     public function renderMetaAttributes(string $property): string
     {
-        if (!$this->templateTransfer->metaAttributes->offsetExists($property)) {
+        $metaAttributes = $this->templateTransfer->metaAttributes[$property] ?? null;
+        if ($metaAttributes === null) {
             return '';
         }
 
-        $metaAttributes = $this->renderIterable(
-            /** @phpstan-ignore argument.type */
-            iterable: $this->templateTransfer->metaAttributes[$property],
+        $renderedMetaAttributes = $this->renderIterable(
+            iterable: $metaAttributes,
             template: self::META_ATTRIBUTE_TEMPLATE,
         );
 
-        return PHP_EOL . $metaAttributes;
+        return PHP_EOL . $renderedMetaAttributes;
     }
 
     public function renderDocBlock(string $property): string
     {
-        if (!$this->templateTransfer->docBlocks->offsetExists($property)) {
+        $docBlocks = $this->templateTransfer->docBlocks[$property] ?? null;
+        if ($docBlocks === null) {
             return '';
         }
 
-        return sprintf(
-            self::DOC_BLOCK_TEMPLATE,
-            $this->templateTransfer->docBlocks[$property],
-        );
+        return sprintf(self::DOC_BLOCK_TEMPLATE, $docBlocks);
     }
 
     public function renderPropertyAttributes(string $property): string
     {
-        if (!$this->templateTransfer->propertyAttributes->offsetExists($property)) {
+        $attributes = $this->templateTransfer->propertyAttributes[$property] ?? null;
+        if ($attributes === null) {
             return '';
         }
 
-        $attributes = $this->renderIterable(
-            /** @phpstan-ignore argument.type */
-            iterable: $this->templateTransfer->propertyAttributes[$property],
+        $renderedAttributes = $this->renderIterable(
+            iterable: $attributes,
             template: self::PROPERTY_ATTRIBUTE_TEMPLATE,
         );
 
-        return PHP_EOL . $attributes;
+        return PHP_EOL . $renderedAttributes;
     }
 }
diff --git a/tests/integration/DefinitionGenerator/Generated/Tagesschau/NewsTransfer.php b/tests/integration/DefinitionGenerator/Generated/Tagesschau/NewsTransfer.php
index 83f7d10c..0c5eeda7 100644
--- a/tests/integration/DefinitionGenerator/Generated/Tagesschau/NewsTransfer.php
+++ b/tests/integration/DefinitionGenerator/Generated/Tagesschau/NewsTransfer.php
@@ -37,7 +37,7 @@ final class NewsTransfer extends AbstractTransfer
         self::REGION_ID_PROP => self::REGION_ID_INDEX,
         self::REGION_IDS_PROP => self::REGION_IDS_INDEX,
         self::RESSORT_PROP => self::RESSORT_INDEX,
-        self::SHARE_U_R_L_PROP => self::SHARE_U_R_L_INDEX,
+        self::SHARE_URL_PROP => self::SHARE_URL_INDEX,
         self::SOPHORA_ID_PROP => self::SOPHORA_ID_INDEX,
         self::TAGS_PROP => self::TAGS_INDEX,
         self::TEASER_IMAGE_PROP => self::TEASER_IMAGE_INDEX,
@@ -200,13 +200,13 @@ final class NewsTransfer extends AbstractTransfer
     }
 
     // shareURL
-    public const string SHARE_U_R_L_PROP = 'shareURL';
-    private const int SHARE_U_R_L_INDEX = 12;
+    public const string SHARE_URL_PROP = 'shareURL';
+    private const int SHARE_URL_INDEX = 12;
 
     public ?string $shareURL {
-        get => $this->getData(self::SHARE_U_R_L_INDEX);
+        get => $this->getData(self::SHARE_URL_INDEX);
         set {
-            $this->setData(self::SHARE_U_R_L_INDEX, $value);
+            $this->setData(self::SHARE_URL_INDEX, $value);
         }
     }
 
diff --git a/tests/integration/Transfer/Generated/SymfonyAttributeTransfer.php b/tests/integration/Transfer/Generated/SymfonyAttributeTransfer.php
index 30e41cdc..1c9e60dc 100644
--- a/tests/integration/Transfer/Generated/SymfonyAttributeTransfer.php
+++ b/tests/integration/Transfer/Generated/SymfonyAttributeTransfer.php
@@ -5,7 +5,7 @@
 namespace Picamator\Tests\Integration\TransferObject\Transfer\Generated;
 
 use Picamator\TransferObject\Transfer\AbstractTransfer;
-use Symfony\Component\Validator\Constraints\IsTrue;
+use Symfony\Component\Validator\Constraints\Length;
 use Symfony\Component\Validator\Constraints\NotBlank;
 
 /**
@@ -29,9 +29,9 @@ final class SymfonyAttributeTransfer extends AbstractTransfer
     public const string I_AM_ASSERT_PROP = 'iAmAssert';
     private const int I_AM_ASSERT_INDEX = 0;
 
-    #[IsTrue]
     #[NotBlank]
-    public ?bool $iAmAssert {
+    #[Length(min: 50)]
+    public string $iAmAssert {
         get => $this->getData(self::I_AM_ASSERT_INDEX);
         set {
             $this->setData(self::I_AM_ASSERT_INDEX, $value);
diff --git a/tests/integration/Transfer/TransferTest.php b/tests/integration/Transfer/TransferTest.php
index 76b988d6..339103ea 100644
--- a/tests/integration/Transfer/TransferTest.php
+++ b/tests/integration/Transfer/TransferTest.php
@@ -477,6 +477,7 @@ public function testSymfonyAssertAttribute(): void
     {
         // Arrange
         $symfonyAttributeTransfer = new SymfonyAttributeTransfer();
+        $symfonyAttributeTransfer->iAmAssert = 'Short text';
 
         $validator = Validation::createValidatorBuilder()
             ->enableAttributeMapping()
@@ -487,7 +488,10 @@ public function testSymfonyAssertAttribute(): void
 
         // Assert
         $this->assertCount(1, $actual, 'Expected one error message');
-        $this->assertSame('This value should not be blank.', $actual[0]?->getMessage());
+
+        /** @var string $message */
+        $message = $actual[0]?->getMessage() ?? '';
+        $this->assertStringStartsWith('This value is too short.', $message);
     }
 
     #[TestDox('Reserved constant should not collide with transfer')]
diff --git a/tests/integration/Transfer/data/config/definition/symfony-attributes.transfer.yml b/tests/integration/Transfer/data/config/definition/symfony-attributes.transfer.yml
index 5af37595..fbbfc6db 100644
--- a/tests/integration/Transfer/data/config/definition/symfony-attributes.transfer.yml
+++ b/tests/integration/Transfer/data/config/definition/symfony-attributes.transfer.yml
@@ -1,7 +1,8 @@
 # $schema: ./../../../../../../schema/definition.schema.json
 SymfonyAttribute:
   iAmAssert:
-    type: bool
+    type: string
+    required:
     attributes:
-      - "sf-assert: IsTrue"
       - "sf-assert:NotBlank"
+      - "sf-assert:Length(min: 50)"
diff --git a/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilderTest.php b/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilderTest.php
new file mode 100644
index 00000000..7b876c18
--- /dev/null
+++ b/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/AttributesNamespaceBuilderTest.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Tests\Unit\TransferObject\TransferGenerator\Definition\Parser\Expander\Builder;
+
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\TestDox;
+use PHPUnit\Framework\Attributes\TestWith;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Picamator\TransferObject\Generated\DefinitionNamespaceTransfer;
+use Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander\Builder\AttributesNamespaceBuilder;
+use Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander\Builder\NamespaceBuilderInterface;
+
+#[Group('transfer-generator')]
+final class AttributesNamespaceBuilderTest extends TestCase
+{
+    private NamespaceBuilderInterface $builder;
+
+    private NamespaceBuilderInterface&MockObject $namespaceBuilderMock;
+
+    protected function setUp(): void
+    {
+        $this->namespaceBuilderMock = $this->createMock(NamespaceBuilderInterface::class);
+
+        $this->builder = new AttributesNamespaceBuilder($this->namespaceBuilderMock);
+    }
+
+    #[TestDox('Create Attribute Namespace replacing shortcuts $namespace to $expected')]
+    #[TestWith(['sf-assert:NotBlank', 'Symfony\Component\Validator\Constraints\NotBlank'])]
+    #[TestWith(['sf-assert:  NotBlank', 'Symfony\Component\Validator\Constraints\NotBlank'])]
+    #[TestWith(['NotBlank', 'NotBlank'])]
+    public function testCreateNamespaceTransfer(string $namespace, string $expected): void
+    {
+        // Arrange
+        $namespaceTransfer = new DefinitionNamespaceTransfer();
+
+        // Expect
+        $this->namespaceBuilderMock->expects($this->once())
+            ->method('createNamespaceTransfer')
+            ->with($expected)
+            ->willReturn($namespaceTransfer)
+            ->seal();
+
+        // Act
+        $this->builder->createNamespaceTransfer($namespace);
+    }
+}
diff --git a/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/NamespaceBuilderTest.php b/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/NamespaceBuilderTest.php
index a43ba157..972a2511 100644
--- a/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/NamespaceBuilderTest.php
+++ b/tests/unit/TransferGenerator/Definition/Parser/Expander/Builder/NamespaceBuilderTest.php
@@ -26,9 +26,9 @@ protected function setUp(): void
     /**
      * @param array<string,mixed> $expected
      */
-    #[DataProvider('definitionNamespaceDataProvider')]
-    #[TestDoxFormatter('definitionNamespaceTestDoxFormatter')]
-    public function testCreateDefinitionNamespaceTransfer(string $namespace, array $expected): void
+    #[DataProvider('namespaceDataProvider')]
+    #[TestDoxFormatter('namespaceTestDoxFormatter')]
+    public function testCreateNamespaceTransfer(string $namespace, array $expected): void
     {
         // Act
         $actual = $this->builder->createNamespaceTransfer($namespace);
@@ -40,7 +40,7 @@ public function testCreateDefinitionNamespaceTransfer(string $namespace, array $
     /**
      * @param array<string,mixed> $expected
      */
-    public static function definitionNamespaceTestDoxFormatter(string $namespace, array $expected): string
+    public static function namespaceTestDoxFormatter(string $namespace, array $expected): string
     {
         return sprintf(
             'Definition namespace "%s" expected "%s"',
@@ -52,7 +52,7 @@ public static function definitionNamespaceTestDoxFormatter(string $namespace, ar
     /**
      * @return Generator<string,mixed>
      */
-    public static function definitionNamespaceDataProvider(): Generator
+    public static function namespaceDataProvider(): Generator
     {
         yield 'namespace without alias' => [
             '\Picamator\TransferObject\Generated',
diff --git a/tests/unit/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpanderTest.php b/tests/unit/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpanderTest.php
index 1a3df6be..1e421890 100644
--- a/tests/unit/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpanderTest.php
+++ b/tests/unit/TransferGenerator/Generator/Render/Expander/MetaConstantsTemplateExpanderTest.php
@@ -28,6 +28,12 @@ protected function setUp(): void
     #[TestWith(['UPPERCASE', 'UPPERCASE'])]
     #[TestWith(['UPPER_CASE', 'UPPER_CASE'])]
     #[TestWith(['Mixed_CaSE', 'MIXED_CASE'])]
+    #[TestWith(['snake_case', 'SNAKE_CASE'])]
+    #[TestWith(['PascalCase', 'PASCAL_CASE'])]
+    #[TestWith(['property1', 'PROPERTY1'])]
+    #[TestWith(['HTTPResponse', 'HTTP_RESPONSE'])]
+    #[TestWith(['myAPIKey', 'MY_API_KEY'])]
+    #[TestWith(['XMLHttpRequest', 'XML_HTTP_REQUEST'])]
     public function testExpandTemplateTransfer(string $propertyName, string $expected): void
     {
         // Arrange