fix(discovery): allow for tools without an input schema

Author: EdouardCourty

src/DependencyInjection/CompilerPass/ToolPass.php

@@ -97,7 +97,7 @@ public function process(ContainerBuilder $container): void
 
             $inputSchemaClassName = $invokeMethodParameter?->getType()?->getName(); // @phpstan-ignore method.notFound
             $inputSchema = $invokeMethodParameter === null
-                ? []
+                ? null
                 : $schemaExtractor->extract($inputSchemaClassName);
 
             $definition->addTag(name: 'mcp_server.tool', attributes: [

src/Service/ToolRegistry.php

@@ -65,7 +65,7 @@ public function getToolsDefinitions(): array
     public function addToolDefinition(
         string $name,
         string $description,
-        array $inputSchema,
+        ?array $inputSchema,
         ?string $inputSchemaClass,
         array $annotations,
     ): void {

src/Tool/ToolDefinition.php

@@ -28,7 +28,7 @@ class ToolDefinition
     public function __construct(
         public string $name,
         public string $description,
-        public array $inputSchema,
+        public ?array $inputSchema,
         #[Ignore]
         public ?string $inputSchemaClass,
         public array $annotations,

tests/Controller/EntrypointControllerTest.php

@@ -151,8 +151,7 @@ public function testToolList(): void
             'openWorldHint' => false,
         ], $tools[0]['annotations']);
 
-        $this->assertArrayHasKey('inputSchema', $tools[1]);
-        $this->assertSame([], $tools[1]['inputSchema']);
+        $this->assertArrayNotHasKey('inputSchema', $tools[1]);
 
         $this->assertArrayHasKey('inputSchema', $tools[2]);
         $this->assertSame([