Add provider hook for preparing function declarations

src/Providers/OpenAiCompatibleImplementation/AbstractOpenAiCompatibleTextGenerationModel.php

@@ -492,6 +492,7 @@ protected function prepareToolsParam(array $functionDeclarations): array
     {
         $tools = [];
         foreach ($functionDeclarations as $functionDeclaration) {
+            $functionDeclaration = $this->prepareFunctionDeclarationForRequest($functionDeclaration);
             $tools[] = [
                 'type' => 'function',
                 'function' => $functionDeclaration->toArray(),
@@ -501,6 +502,23 @@ protected function prepareToolsParam(array $functionDeclarations): array
         return $tools;
     }
 
+    /**
+     * Prepares a function declaration for the provider request.
+     *
+     * Providers can override this method to adapt a function declaration's
+     * input schema to the compatibility requirements of their API.
+     *
+     * @since n.e.x.t
+     *
+     * @param FunctionDeclaration $functionDeclaration The function declaration.
+     * @return FunctionDeclaration The prepared function declaration.
+     */
+    protected function prepareFunctionDeclarationForRequest(
+        FunctionDeclaration $functionDeclaration
+    ): FunctionDeclaration {
+        return $functionDeclaration;
+    }
+
     /**
      * Prepares the response format parameter for the API request.
      *

tests/unit/Providers/OpenAiCompatibleImplementation/AbstractOpenAiCompatibleTextGenerationModelTest.php

@@ -926,6 +926,44 @@ public function testPrepareToolsParam(): void
         $this->assertEquals($functionDeclaration2->toArray(), $prepared[1]['function']);
     }
 
+    /**
+     * Tests that providers can customize function declarations before serialization.
+     *
+     * @return void
+     */
+    public function testPrepareToolsParamAllowsProviderCustomization(): void
+    {
+        $functionDeclaration = new FunctionDeclaration(
+            'original_name',
+            'Description',
+            ['type' => 'object']
+        );
+        $model = new class (
+            $this->modelMetadata,
+            $this->providerMetadata,
+            $this->mockHttpTransporter,
+            $this->mockRequestAuthentication
+        ) extends MockOpenAiCompatibleTextGenerationModel {
+            /**
+             * {@inheritDoc}
+             */
+            protected function prepareFunctionDeclarationForRequest(
+                FunctionDeclaration $functionDeclaration
+            ): FunctionDeclaration {
+                return new FunctionDeclaration(
+                    $functionDeclaration->getName() . '_prepared',
+                    $functionDeclaration->getDescription(),
+                    $functionDeclaration->getParameters()
+                );
+            }
+        };
+
+        $prepared = $model->exposePrepareToolsParam([$functionDeclaration]);
+
+        $this->assertSame('original_name_prepared', $prepared[0]['function']['name']);
+        $this->assertSame(['type' => 'object'], $prepared[0]['function']['parameters']);
+    }
+
     /**
      * Tests prepareResponseFormatParam() with null schema.
      *