diff --git a/tests/test_api_surface.py b/tests/test_api_surface.py
new file mode 100644
index 0000000..6575e14
--- /dev/null
+++ b/tests/test_api_surface.py
@@ -0,0 +1,73 @@
+"""Przypina powierzchnię API - panel jest osobnym klientem, więc kontrakt musi być stabilny."""
+
+from __future__ import annotations
+
+import tempfile
+import unittest
+
+from zyrarbot.application import Application
+from zyrarbot.settings import Settings
+
+EXPECTED_ENDPOINTS = {
+    ("get", "/api/status"),
+    ("post", "/api/play"),
+    ("post", "/api/play_file"),
+    ("post", "/api/pause"),
+    ("post", "/api/resume"),
+    ("post", "/api/skip"),
+    ("post", "/api/stop"),
+    ("post", "/api/volume"),
+    ("post", "/api/loop"),
+    ("post", "/api/loop_playlist"),
+    ("post", "/api/loop_cycle"),
+    ("post", "/api/jump"),
+    ("post", "/api/remove"),
+    ("post", "/api/reorder"),
+    ("post", "/api/queue/plays"),
+    ("get", "/api/uploads"),
+    ("post", "/api/upload"),
+    ("delete", "/api/uploads/{filename}"),
+    ("post", "/api/connect"),
+    ("post", "/api/disconnect"),
+    ("post", "/api/settings/text_channel"),
+    ("post", "/api/settings/default_plays"),
+}
+
+
+class ApiSurfaceTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        cls._workdir = tempfile.TemporaryDirectory()
+        settings = Settings(
+            discord_token="test",
+            config_dir=f"{cls._workdir.name}/config",
+            uploads_dir=f"{cls._workdir.name}/uploads",
+            static_dir=f"{cls._workdir.name}/static",
+        )
+        cls.spec = Application(settings).api.openapi()
+
+    @classmethod
+    def tearDownClass(cls) -> None:
+        cls._workdir.cleanup()
+
+    def _declared(self) -> set[tuple[str, str]]:
+        return {
+            (method, path)
+            for path, operations in self.spec["paths"].items()
+            for method in operations
+        }
+
+    def test_all_expected_endpoints_are_declared(self):
+        self.assertEqual(set(), EXPECTED_ENDPOINTS - self._declared())
+
+    def test_no_endpoint_added_without_updating_this_test(self):
+        # Panel jest odrębnym klientem - nowa trasa powinna trafić tu świadomie.
+        self.assertEqual(set(), self._declared() - EXPECTED_ENDPOINTS)
+
+    def test_openapi_document_is_well_formed(self):
+        self.assertTrue(self.spec["openapi"].startswith("3."))
+        self.assertIn("ŻyrarBOT", self.spec["info"]["title"])
+
+
+if __name__ == "__main__":
+    unittest.main()