Google rewrites descriptions often. Write one anyway. When it is used, it is the only pitch you get besides the title.
Length
Stay near 150–160 characters. Shorter is fine if every word works. Longer gets ellipsed.
The SEO title and meta generator on this site counts both.
What to say
- Restate the promise from the title in different words
- Name who it is for
- Add one concrete detail (price, count, time, format)
Bad: "Welcome to our blog where we share insights." Good: "Draft keyword-first titles and meta descriptions with live length checks. Free, in the browser."
Do not stuff
Repeating the keyword five times reads like 2012. One clear use of the phrase is enough if the H1 and the body already cover it.