diff --git a/ai/backend-context.md b/ai/backend-context.md
index dd69678..34729b2 100644
--- a/ai/backend-context.md
+++ b/ai/backend-context.md
@@ -20,6 +20,9 @@ intentionally omitted here - update this section as entities land.
   - Do not write unit tests for concrete repository implementations
     (e.g. `Postgres*Repository`). They are exercised by e2e tests.
     Use cases are tested with fake repositories.
+  - Do not write reflection-only contract tests for repository interface
+    method names, parameter counts, parameter names, or type hints. PHP
+    interfaces already enforce those signatures; test behavior instead.
   - Repository methods that find records by a foreign key should accept
     the related entity, not a raw id (e.g. `findBySet(Set $set)`, not
     `findBySetId(int $setId)`).
diff --git a/backend/tests/Unit/Element/ElementRepositoryContractTest.php b/backend/tests/Unit/Element/ElementRepositoryContractTest.php
deleted file mode 100644
index 84e5bb9..0000000
--- a/backend/tests/Unit/Element/ElementRepositoryContractTest.php
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-
-namespace Tests\Unit\Element;
-
-use App\Element\Element;
-use App\Element\ElementRepository;
-use ReflectionMethod;
-use Tests\TestCase;
-
-class ElementRepositoryContractTest extends TestCase
-{
-    public function testUpdateAcceptsOnlyElement(): void
-    {
-        $method = new ReflectionMethod(ElementRepository::class, 'update');
-        $parameters = $method->getParameters();
-
-        $this->assertCount(1, $parameters);
-        $this->assertSame('element', $parameters[0]->getName());
-        $this->assertSame(
-            Element::class,
-            $parameters[0]->getType()->getName(),
-        );
-    }
-}