assertEquals(LlmException.ERROR_AUTH, exception.getErrorCode());
        assertSame(cause, exception.getCause());
    }

    @Test
    public void test_errorCodeConstants() {
        assertEquals("rate_limit", LlmException.ERROR_RATE_LIMIT);
        assertEquals("auth_error", LlmException.ERROR_AUTH);
        assertEquals("service_unavailable", LlmException.ERROR_SERVICE_UNAVAILABLE);