When it comes to Android devices, it's common for various phone makers to put their own software over Google's clean version of Android.

If you swipe through one of Samsung's Galaxy phones, for example, you're likely to come across some of Samsung's apps and its own Galaxy app store.

Now, however, it seem that Google wants its partners to put its own apps and services at the forefront of most Android phones.

Amir Efrati at The Information says he has obtained confidential documents the reveal Google has been upping its requirements for partners that want to build Android phones.

In particular, the documents suggest Google wants its partners to place more of its apps on Android phones and feature them in more prominent places.

One reason for this change is that Google wants the Android experience to be more consistent across devices, Efrati reports. This means Google would turn down certain customizations proposed by phone makers, and Efrati notes that "there have been frequent fights about that, particularly between Google and Samsung."

This wouldn't be too surprising — Samsung is known for adding its own TouchWiz software to its Android devices. The company also emphasizes its own software features and apps when promoting its new phones.

While Samsung is one of Google's biggest partners, its also its most formidable rival when it comes to the smartphone space. Samsung's incredibly popular Galaxy phones compete directly with Google's Nexus devices and other smartphones, such as Motorola's, that use near-stock versions of Android.

The Samsung Galaxy S5 Steve Kovach/Business Insider Google's partners are reportedly saying the company is "tightening the screws" on these Android contracts, known as Mobile Application Distribution Agreements, according to Efrati.

But many of these manufacturers feel as if they don't have a choice since other operating systems such as Windows Phone, Tizen, and Firefox OS have limited reach. Android currently commands an overwhelming 85% of the global smartphone market as of July 2014, according to Strategy Analytics.

As part of the updated contract, Google is requiring one of its partners to increase the number of Google-made apps from nine in 2011 to 20 in 2014. This year's agreement also required that there must be a Google search widget on the default home screen of the phone along with an icon for the Google Play store and a Google icon that houses 13 apps included "Google Chrome, Google Maps, Google Drive, YouTube, and Gmail among others.

Google is also reportedly requiring partners to follow its guidelines regarding hotwords for voice-enabled searches and virtual assistants.

It's unclear exactly what the impact of these new contracts will be, but if Efrati's report is legitimate this may mean we'll be seeing less customization from some of Google's partners. Samsung has already been putting more of its resources into Tizen, a different open-source software based on Linux.

The company's new Gear S smartwatch, for example, runs on Tizen, but we have yet to see a mainstream phone from Samsung that runs on something other than Android.