diff --git a/strix/core/execution.py b/strix/core/execution.py
index 508eccfe..5997e3db 100644
--- a/strix/core/execution.py
+++ b/strix/core/execution.py
@@ -184,9 +184,7 @@ def _is_transient_model_error(exc: BaseException) -> bool:
         return True
     code = _model_error_status_code(exc)
     if code is not None:
-        import litellm
-
-        return bool(litellm._should_retry(code))
+        return code >= 400 and code not in (401, 402, 403, 404)
     return isinstance(exc, APIError)
 
 
diff --git a/tests/test_execution_transient_retry.py b/tests/test_execution_transient_retry.py
index 57b26db3..f0276932 100644
--- a/tests/test_execution_transient_retry.py
+++ b/tests/test_execution_transient_retry.py
@@ -79,12 +79,13 @@ def test_content_guardrail_is_not_retried() -> None:
     assert execution._is_transient_model_error(guardrail) is False
 
 
-def test_client_errors_are_not_transient() -> None:
+def test_client_errors_are_transient() -> None:
     bad_request = BadRequestError(
         "bad", response=httpx.Response(400, request=_request()), body=None
     )
-    assert execution._is_transient_model_error(bad_request) is False
-    assert execution._is_transient_model_error(_status_error(404)) is False
+    assert execution._is_transient_model_error(bad_request) is True
+    for status in (401, 402, 403, 404):
+        assert execution._is_transient_model_error(_status_error(status)) is False
     assert execution._is_transient_model_error(ValueError("nope")) is False
 
 
@@ -167,11 +168,8 @@ async def test_run_cycle_gives_up_after_max_retries(
 async def test_run_cycle_does_not_retry_permanent_error(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
-    bad_request = BadRequestError(
-        "bad", response=httpx.Response(400, request=_request()), body=None
-    )
-    streams = [_FakeStream(exc=bad_request), _FakeStream()]
-    with pytest.raises(BadRequestError):
+    streams = [_FakeStream(exc=ValueError("nope")), _FakeStream()]
+    with pytest.raises(ValueError, match="nope"):
         await _run_once(monkeypatch, streams)