diff --git a/src/Types/ResumeSessionConfig.php b/src/Types/ResumeSessionConfig.php
index 7efe478..6a86fcd 100644
--- a/src/Types/ResumeSessionConfig.php
+++ b/src/Types/ResumeSessionConfig.php
@@ -14,6 +14,11 @@
 readonly class ResumeSessionConfig implements Arrayable
 {
     public function __construct(
+        /**
+         * Client name to identify the application using the SDK.
+         * Included in the User-Agent header for API requests.
+         */
+        public ?string $clientName = null,
         /**
          * Model to use for this session.
          */
@@ -146,6 +151,7 @@ public static function fromArray(array $data): self
         }
 
         return new self(
+            clientName: $data['clientName'] ?? null,
             model: $data['model'] ?? null,
             reasoningEffort: $data['reasoningEffort'] ?? null,
             configDir: $data['configDir'] ?? null,
@@ -194,6 +200,7 @@ public function toArray(): array
             : $this->hooks;
 
         return array_filter([
+            'clientName' => $this->clientName,
             'model' => $this->model,
             'reasoningEffort' => $reasoningEffort,
             'configDir' => $this->configDir,
diff --git a/src/Types/SessionConfig.php b/src/Types/SessionConfig.php
index 25a3f2b..14756d2 100644
--- a/src/Types/SessionConfig.php
+++ b/src/Types/SessionConfig.php
@@ -19,6 +19,11 @@ public function __construct(
          * If not provided, server will generate one.
          */
         public ?string $sessionId = null,
+        /**
+         * Client name to identify the application using the SDK.
+         * Included in the User-Agent header for API requests.
+         */
+        public ?string $clientName = null,
         /**
          * Model to use for this session.
          */
@@ -145,6 +150,7 @@ public static function fromArray(array $data): self
 
         return new self(
             sessionId: $data['sessionId'] ?? null,
+            clientName: $data['clientName'] ?? null,
             model: $data['model'] ?? null,
             reasoningEffort: $data['reasoningEffort'] ?? null,
             configDir: $data['configDir'] ?? null,
@@ -193,6 +199,7 @@ public function toArray(): array
 
         return array_filter([
             'sessionId' => $this->sessionId,
+            'clientName' => $this->clientName,
             'model' => $this->model,
             'reasoningEffort' => $reasoningEffort,
             'configDir' => $this->configDir,
diff --git a/tests/Unit/Types/ResumeSessionConfigTest.php b/tests/Unit/Types/ResumeSessionConfigTest.php
index 1291714..64decc1 100644
--- a/tests/Unit/Types/ResumeSessionConfigTest.php
+++ b/tests/Unit/Types/ResumeSessionConfigTest.php
@@ -16,6 +16,7 @@
         $preToolUseHook = fn () => null;
 
         $config = ResumeSessionConfig::fromArray([
+            'clientName' => 'my-app',
             'model' => 'claude-opus-4.6',
             'reasoningEffort' => ReasoningEffort::XHIGH,
             'configDir' => './src',
@@ -38,6 +39,7 @@
         ]);
 
         expect($config->tools)->toBe([['name' => 'test_tool']])
+            ->and($config->clientName)->toBe('my-app')
             ->and($config->model)->toBe('claude-opus-4.6')
             ->and($config->reasoningEffort)->toBe(ReasoningEffort::XHIGH)
             ->and($config->systemMessage->content)->toBe('Instructions')
@@ -96,6 +98,7 @@
         $preToolUseHook = fn () => null;
 
         $config = new ResumeSessionConfig(
+            clientName: 'my-app',
             model: 'claude-opus-4.6',
             reasoningEffort: ReasoningEffort::XHIGH,
             configDir: './src',
@@ -120,6 +123,7 @@
         $array = $config->toArray();
 
         expect($array['tools'])->toBe([['name' => 'tool1']])
+            ->and($array['clientName'])->toBe('my-app')
             ->and($array['provider'])->toBe(['baseUrl' => 'https://api.test.com'])
             ->and($array['onPermissionRequest'])->toBe($handler)
             ->and($array['onUserInputRequest'])->toBe($userInputHandler)
diff --git a/tests/Unit/Types/SessionConfigTest.php b/tests/Unit/Types/SessionConfigTest.php
index bae29e3..eaee2fa 100644
--- a/tests/Unit/Types/SessionConfigTest.php
+++ b/tests/Unit/Types/SessionConfigTest.php
@@ -17,6 +17,7 @@
 
         $config = SessionConfig::fromArray([
             'sessionId' => 'test-session-id',
+            'clientName' => 'my-app',
             'model' => 'claude-sonnet-4.5',
             'configDir' => '/tmp/config',
             'tools' => [['name' => 'test_tool']],
@@ -37,6 +38,7 @@
         ]);
 
         expect($config->sessionId)->toBe('test-session-id')
+            ->and($config->clientName)->toBe('my-app')
             ->and($config->model)->toBe('claude-sonnet-4.5')
             ->and($config->configDir)->toBe('/tmp/config')
             ->and($config->tools)->toBe([['name' => 'test_tool']])
@@ -63,6 +65,7 @@
         $config = SessionConfig::fromArray([]);
 
         expect($config->sessionId)->toBeNull()
+            ->and($config->clientName)->toBeNull()
             ->and($config->model)->toBeNull()
             ->and($config->configDir)->toBeNull()
             ->and($config->tools)->toBeNull()
@@ -107,6 +110,7 @@
 
         $config = new SessionConfig(
             sessionId: 'session-123',
+            clientName: 'my-app',
             model: 'gpt-4',
             configDir: '/config',
             tools: [['name' => 'tool1']],
@@ -129,6 +133,7 @@
         $array = $config->toArray();
 
         expect($array['sessionId'])->toBe('session-123')
+            ->and($array['clientName'])->toBe('my-app')
             ->and($array['model'])->toBe('gpt-4')
             ->and($array['configDir'])->toBe('/config')
             ->and($array['tools'])->toBe([['name' => 'tool1']])