diff --git a/src/Server/Http/Controllers/OAuthRegisterController.php b/src/Server/Http/Controllers/OAuthRegisterController.php
index 00bf28fd6..b5115b654 100644
--- a/src/Server/Http/Controllers/OAuthRegisterController.php
+++ b/src/Server/Http/Controllers/OAuthRegisterController.php
@@ -21,8 +21,8 @@ class OAuthRegisterController
     public function __invoke(Request $request): JsonResponse
     {
         $validator = Validator::make($request->all(), [
-            'client_name' => ['nullable', 'string', 'min:1', 'max:255', 'required_without:name'],
-            'name' => ['nullable', 'string', 'min:1', 'max:255', 'required_without:client_name'],
+            'client_name' => ['nullable', 'string', 'min:1', 'max:255'],
+            'name' => ['nullable', 'string', 'min:1', 'max:255'],
             'redirect_uris' => ['required', 'array', 'min:1'],
             'redirect_uris.*' => ['required', 'string', function (string $attribute, $value, $fail): void {
                 if (! $this->isValidRedirectUri($value)) {
@@ -76,7 +76,7 @@ public function __invoke(Request $request): JsonResponse
         );
 
         $client = $clients->createAuthorizationCodeGrantClient(
-            name: $validated['client_name'] ?? $validated['name'],
+            name: $this->resolveClientName($validated),
             redirectUris: $validated['redirect_uris'],
             confidential: false,
             enableDeviceFlow: false,
@@ -92,6 +92,18 @@ public function __invoke(Request $request): JsonResponse
         ], 201);
     }
 
+    /**
+     * Resolve the client name, falling back to the redirect host or a default.
+     *
+     * @param  array<string, mixed>  $validated
+     */
+    protected function resolveClientName(array $validated): string
+    {
+        return $validated['client_name']
+            ?? $validated['name']
+            ?? (parse_url((string) ($validated['redirect_uris'][0] ?? ''), PHP_URL_HOST) ?: 'MCP Client');
+    }
+
     protected function isValidRedirectUri(string $value): bool
     {
         $scheme = parse_url($value, PHP_URL_SCHEME);
diff --git a/tests/Unit/Server/RegistrarTest.php b/tests/Unit/Server/RegistrarTest.php
index 666c83205..4919262e5 100644
--- a/tests/Unit/Server/RegistrarTest.php
+++ b/tests/Unit/Server/RegistrarTest.php
@@ -221,7 +221,7 @@ function ensureMockClientRepository(): void
     ]);
 });
 
-it('requires an oauth client name for registration', function (): void {
+it('falls back to the redirect host when no client name is provided', function (): void {
     $clientRepository = new class
     {
         public ?string $capturedName = null;
@@ -244,7 +244,25 @@ public function createAuthorizationCodeGrantClient(string $name, array $redirect
     $this->app->instance(ClientRepository::class, $clientRepository);
 
     $response = $this->postJson('/oauth/register', [
-        'redirect_uris' => ['http://localhost:3000/callback'],
+        'redirect_uris' => ['https://example.com/callback'],
+    ]);
+
+    $response->assertStatus(201);
+
+    expect($clientRepository->capturedName)->toBe('example.com');
+});
+
+it('returns invalid_client_metadata when client metadata is invalid', function (): void {
+    ensureMockClientRepository();
+
+    $registrar = new Registrar;
+    $registrar->oauthRoutes();
+
+    $this->app->instance(ClientRepository::class, new ClientRepository);
+
+    $response = $this->postJson('/oauth/register', [
+        'client_name' => str_repeat('a', 256),
+        'redirect_uris' => ['https://example.com/callback'],
     ]);
 
     $response->assertStatus(400);
@@ -253,6 +271,38 @@ public function createAuthorizationCodeGrantClient(string $name, array $redirect
     ]);
 });
 
+it('preserves a falsy client name for oauth registration', function (): void {
+    $clientRepository = new class
+    {
+        public ?string $capturedName = null;
+
+        public function createAuthorizationCodeGrantClient(string $name, array $redirectUris, bool $confidential = true, $user = null, bool $enableDeviceFlow = false)
+        {
+            $this->capturedName = $name;
+
+            return (object) [
+                'id' => 'test-client-id',
+                'grant_types' => ['authorization_code'],
+                'redirect_uris' => $redirectUris,
+            ];
+        }
+    };
+
+    $registrar = new Registrar;
+    $registrar->oauthRoutes();
+
+    $this->app->instance(ClientRepository::class, $clientRepository);
+
+    $response = $this->postJson('/oauth/register', [
+        'client_name' => '0',
+        'redirect_uris' => ['https://example.com/callback'],
+    ]);
+
+    $response->assertStatus(201);
+
+    expect($clientRepository->capturedName)->toBe('0');
+});
+
 it('falls back to the legacy name field for oauth registration', function (): void {
     $clientRepository = new class
     {
@@ -699,7 +749,7 @@ public function createAuthorizationCodeGrantClient(string $name, array $redirect
     $this->app->instance(ClientRepository::class, new ClientRepository);
 
     $response = $this->post('/oauth/register', [
-        'redirect_uris' => ['http://localhost:3000/callback'],
+        'redirect_uris' => ['not-a-valid-url'],
     ], ['Accept' => '*/*']);
 
     $response->assertStatus(400);