diff --git a/src/pyrecest/_backend/capabilities.py b/src/pyrecest/_backend/capabilities.py
index 43bade893..cb545daf5 100644
--- a/src/pyrecest/_backend/capabilities.py
+++ b/src/pyrecest/_backend/capabilities.py
@@ -203,7 +203,9 @@ def get_api_backend_support(api_name: str) -> dict[str, str]:
 
 def iter_api_backend_capabilities() -> tuple[tuple[str, dict[str, str]], ...]:
     """Return public API backend support rows in a stable order."""
-    return tuple(sorted(API_BACKEND_CAPABILITIES.items()))
+    return tuple(
+        (api_name, dict(row)) for api_name, row in sorted(API_BACKEND_CAPABILITIES.items())
+    )
 
 
 def validate_api_backend_capabilities() -> tuple[str, ...]:
diff --git a/tests/test_backend_capabilities.py b/tests/test_backend_capabilities.py
index 3d758e029..8ada79e96 100644
--- a/tests/test_backend_capabilities.py
+++ b/tests/test_backend_capabilities.py
@@ -20,6 +20,15 @@ def test_api_backend_capability_rows_have_valid_support_levels() -> None:
         assert support.get("notes")
 
 
+def test_iter_api_backend_capabilities_returns_row_copies() -> None:
+    api_name, support = iter_api_backend_capabilities()[0]
+    original_notes = API_BACKEND_CAPABILITIES[api_name]["notes"]
+
+    support["notes"] = "mutated by caller"
+
+    assert API_BACKEND_CAPABILITIES[api_name]["notes"] == original_notes
+
+
 def test_cli_backends_reports_machine_readable_capabilities(capsys) -> None:
     assert cli_main(["backends"]) == 0
     payload = json.loads(capsys.readouterr().out)