With the Google mobile first index still in progress on Google’s end, Gary Illyes dropped an idea to SEO tool builders on what tools they should build next to help SEOs prepare for the mobile-first index launch.
He basically said you should create a tool that compares your desktop sites to your mobile friendly sites and see what is missing between the tool. Specifically, it should look for these differences:
Critical content
Metadata, like hreflang
Images and videos
Structured data
Probably another one that makes sense, which is probably part of Gary’s “critical content” point is to make sure your internal linking structure doesn’t change too much between desktop and mobile.

2/2 Compare these on desktop and smartphone pages:1. Critical content2. Metadata, like hreflang3. Images and videos4. Structured data
— Gary “鯨理” Illyes (@methode) September 4, 2017
He said the tool should return a “not mobile friendly ready” status if any of the above fail.
Of course, Gary would not give any update on timelines with the mobile-first index release:

No update on the timing, at least not today. We’ll share it with y’all when we have something
— Gary “鯨理” Illyes (@methode) September 4, 2017
I like the idea of this tool and I was hoping Google would come up with one in Google Search Console.
Forum discussion at Twitter.

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