diff --git a/composer.json b/composer.json
index 50415b2..77dd12f 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     ],
     "require": {
         "php": "^8.2",
-        "papi-ai/papi-core": "^0.14",
+        "papi-ai/papi-core": "^0.15",
         "ext-curl": "*"
     },
     "require-dev": {
diff --git a/src/DeepSeekProvider.php b/src/DeepSeekProvider.php
index 518de6a..f00c3f0 100644
--- a/src/DeepSeekProvider.php
+++ b/src/DeepSeekProvider.php
@@ -15,6 +15,7 @@
 namespace PapiAI\DeepSeek;
 
 use Generator;
+use PapiAI\Core\Contracts\NamedToolSelectableInterface;
 use PapiAI\Core\Contracts\ProviderInterface;
 use PapiAI\Core\Exception\AuthenticationException;
 use PapiAI\Core\Exception\ProviderException;
@@ -43,13 +44,21 @@
  *
  * @see https://api-docs.deepseek.com/
  *
- * @psalm-import-type ChatOptions from ProviderInterface
+ * @psalm-import-type ChatOptions from ProviderInterface *
+ * The neutral `effort` option is accepted and ignored here. DeepSeek does expose reasoning control, as a nested thinking object rather than a flat level, but papi does not map it yet, so the option is accepted and ignored for now. Ignoring it
+ * degrades nothing the caller was promised, which is why it is silent where an unhonourable
+ * `toolChoice` throws.
  */
-class DeepSeekProvider implements ProviderInterface
+class DeepSeekProvider implements ProviderInterface, NamedToolSelectableInterface
 {
     private const API_URL = 'https://api.deepseek.com/chat/completions';
 
+    public const MODEL_DEEPSEEK_V4_FLASH = 'deepseek-v4-flash';
+    public const MODEL_DEEPSEEK_V4_PRO = 'deepseek-v4-pro';
+
+    /** @deprecated Discontinued 24 July 2026; requests fail. Use MODEL_DEEPSEEK_V4_FLASH. */
     public const MODEL_DEEPSEEK_CHAT = 'deepseek-chat';
+    /** @deprecated Discontinued 24 July 2026; requests fail. Use MODEL_DEEPSEEK_V4_FLASH. */
     public const MODEL_DEEPSEEK_REASONER = 'deepseek-reasoner';
 
     /**
@@ -61,7 +70,7 @@ class DeepSeekProvider implements ProviderInterface
      */
     public function __construct(
         private readonly string $apiKey,
-        private readonly string $defaultModel = self::MODEL_DEEPSEEK_CHAT,
+        private readonly string $defaultModel = self::MODEL_DEEPSEEK_V4_FLASH,
         private readonly int $defaultMaxTokens = 4096,
     ) {
     }
diff --git a/tests/Unit/DeepSeekProviderTest.php b/tests/Unit/DeepSeekProviderTest.php
index de97e3a..1069b35 100644
--- a/tests/Unit/DeepSeekProviderTest.php
+++ b/tests/Unit/DeepSeekProviderTest.php
@@ -138,7 +138,7 @@ public function callThrowForStatusCode(int $httpCode, ?array $data): never
 
             $this->provider->chat([Message::user('Hello')]);
 
-            expect($this->provider->lastPayload['model'])->toBe('deepseek-chat');
+            expect($this->provider->lastPayload['model'])->toBe('deepseek-v4-flash');
         });
 
         it('overrides model and options from parameters', function () {
diff --git a/tests/Unit/DeepSeekToolChoiceTest.php b/tests/Unit/DeepSeekToolChoiceTest.php
index 713f173..bf15154 100644
--- a/tests/Unit/DeepSeekToolChoiceTest.php
+++ b/tests/Unit/DeepSeekToolChoiceTest.php
@@ -12,6 +12,8 @@
 
 declare(strict_types=1);
 
+use PapiAI\Core\Contracts\NamedToolSelectableInterface;
+use PapiAI\Core\Contracts\ToolSelectableInterface;
 use PapiAI\Core\Message;
 use PapiAI\DeepSeek\DeepSeekProvider;
 
@@ -67,3 +69,10 @@ protected function request(array $payload): array
         expect($this->provider->lastPayload)->toBe([]);
     });
 });
+
+describe('DeepSeekProvider tool-selection capability', function () {
+    it('declares what it can force, so callers can ask instead of catching', function () {
+        expect(is_subclass_of(DeepSeekProvider::class, NamedToolSelectableInterface::class))->toBeTrue();
+        expect(is_subclass_of(DeepSeekProvider::class, ToolSelectableInterface::class))->toBeTrue();
+    });
+});