What the tools do, and what they do not
Each tool answers one question about one page. The audit fetches a page the way a search engine would and checks twelve things that are either in place or not: whether the page returns 200, whether it is served over HTTPS, whether it has a title, a description, one H1, a canonical tag, and so on.
The title length checker works before you publish. Type a title and a description and it shows them as a search result, with a count and a verdict for each.
None of them measures rankings, traffic or links from other sites, and a clean result is not a promise of any of those. They tell you whether the basics are right, so the time you spend on the page itself is not wasted on something a search engine cannot read properly.