diff --git a/composer.json b/composer.json
index 995b2ec..99fe5cf 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     ],
     "require": {
         "php": "^8.2",
-        "papi-ai/papi-core": "^0.9",
+        "papi-ai/papi-core": "^0.13",
         "ext-curl": "*"
     },
     "require-dev": {
diff --git a/src/DeepSeekProvider.php b/src/DeepSeekProvider.php
index 2c1d335..518de6a 100644
--- a/src/DeepSeekProvider.php
+++ b/src/DeepSeekProvider.php
@@ -24,6 +24,7 @@
 use PapiAI\Core\Role;
 use PapiAI\Core\StreamChunk;
 use PapiAI\Core\ToolCall;
+use PapiAI\Core\ToolChoice;
 use RuntimeException;
 
 /**
@@ -41,6 +42,8 @@
  *   - deepseek-reasoner (reasoning)
  *
  * @see https://api-docs.deepseek.com/
+ *
+ * @psalm-import-type ChatOptions from ProviderInterface
  */
 class DeepSeekProvider implements ProviderInterface
 {
@@ -70,14 +73,7 @@ public function __construct(
      * and parses the response back into a core Response object.
      *
      * @param array<Message> $messages Conversation history as PapiAI Message objects
-     * @param array{
-     *     model?: string,
-     *     tools?: array,
-     *     maxTokens?: int,
-     *     temperature?: float,
-     *     stopSequences?: array<string>,
-     *     outputSchema?: array,
-     * } $options Request options (model, tools, maxTokens, temperature, etc.)
+     * @param ChatOptions     $options  Request options (model, tools, maxTokens, temperature, toolChoice, etc.)
      *
      * @return Response Parsed response containing text, tool calls, usage, and stop reason
      *
@@ -208,6 +204,21 @@ private function buildPayload(array $messages, array $options): array
             $payload['tools'] = $this->convertTools($options['tools']);
         }
 
+        // Forced tool choice (OpenAI-compatible). Validation lives in core and throws before any HTTP call.
+        if (isset($options['toolChoice'])) {
+            $choice = ToolChoice::fromOption($options['toolChoice'], $options['tools'] ?? []);
+
+            if (!empty($options['tools'])) {
+                $payload['tool_choice'] = $choice->toolName !== null
+                    ? ['type' => 'function', 'function' => ['name' => $choice->toolName]]
+                    : match ($choice->mode) {
+                        ToolChoice::NONE => 'none',
+                        ToolChoice::REQUIRED => 'required',
+                        default => 'auto',
+                    };
+            }
+        }
+
         return $payload;
     }
 
diff --git a/tests/Unit/DeepSeekToolChoiceTest.php b/tests/Unit/DeepSeekToolChoiceTest.php
new file mode 100644
index 0000000..713f173
--- /dev/null
+++ b/tests/Unit/DeepSeekToolChoiceTest.php
@@ -0,0 +1,69 @@
+<?php
+
+/*
+ * This file is part of PapiAI,
+ * A simple but powerful PHP library for building AI agents.
+ *
+ * (c) Marcello Duarte <marcello.duarte@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+use PapiAI\Core\Message;
+use PapiAI\DeepSeek\DeepSeekProvider;
+
+/**
+ * Captures the request payload so tool-choice mapping can be asserted without HTTP.
+ */
+class TestableDeepSeekToolChoiceProvider extends DeepSeekProvider
+{
+    public array $lastPayload = [];
+
+    protected function request(array $payload): array
+    {
+        $this->lastPayload = $payload;
+
+        return ['choices' => [['message' => ['role' => 'assistant', 'content' => 'ok'], 'finish_reason' => 'stop']]];
+    }
+}
+
+describe('DeepSeekProvider tool choice', function () {
+    beforeEach(function () {
+        $this->provider = new TestableDeepSeekToolChoiceProvider('test-api-key');
+        $this->tools = [
+            ['name' => 'get_weather', 'description' => 'Weather', 'parameters' => ['type' => 'object']],
+        ];
+    });
+
+    it('maps auto/none/required to the OpenAI-compatible strings', function () {
+        $this->provider->chat([Message::user('hi')], ['tools' => $this->tools, 'toolChoice' => 'auto']);
+        expect($this->provider->lastPayload['tool_choice'])->toBe('auto');
+
+        $this->provider->chat([Message::user('hi')], ['tools' => $this->tools, 'toolChoice' => 'none']);
+        expect($this->provider->lastPayload['tool_choice'])->toBe('none');
+
+        $this->provider->chat([Message::user('hi')], ['tools' => $this->tools, 'toolChoice' => 'required']);
+        expect($this->provider->lastPayload['tool_choice'])->toBe('required');
+    });
+
+    it('maps a specific tool to the function form', function () {
+        $this->provider->chat([Message::user('hi')], ['tools' => $this->tools, 'toolChoice' => ['name' => 'get_weather']]);
+
+        expect($this->provider->lastPayload['tool_choice'])->toBe(['type' => 'function', 'function' => ['name' => 'get_weather']]);
+    });
+
+    it('emits no tool_choice when absent (backward compatible)', function () {
+        $this->provider->chat([Message::user('hi')], ['tools' => $this->tools]);
+
+        expect($this->provider->lastPayload)->not->toHaveKey('tool_choice');
+    });
+
+    it('throws for an unenforceable choice, before any HTTP call', function () {
+        expect(fn () => $this->provider->chat([Message::user('hi')], ['toolChoice' => 'required']))
+            ->toThrow(InvalidArgumentException::class);
+        expect($this->provider->lastPayload)->toBe([]);
+    });
+});