description - meta tag content

I see how I can add keywords but how can I add/ edit other meta tags? I want to add a ’description’ tag and so on

See http://modxcms.com/extras/package/272

I could just put them in the <head> section of each template with the same result correct?

Yes!!

It’s rocket science

The MODx built in meta keywords are optional to use.
( Related link - I assume it’s using regClientStartup)

You could use your own TV’s wherever you want in the code:
<meta name="..." content="[*textTV*]" />