To add Meta-Keywords and Meta-Description to a frameset in TYPO3 you can use the following snippet, Using this snippets the meta tags are the same for the whole site.

myframeset.meta.keywords=keyword1,keyword2
myframeset.meta.description=the meta description

With this second snippet you can set the meta description and meta keywords per page. You choose page type "advanced" and fill the fields keyword and description.

myframeset.meta.keywords.field=keywords
myframeset.meta.description.field=description

This third snippet sets the keywords through TypoScript. Its adds the field title.

myframesset=PAGE
myframeset.headerData.20 = TEXT
myframeset.headerData.20.insertData=1
myframeset.headerData.20.value={field:title},keyword1,keyword2
myframeset.headerData.20.wrap2 = <meta NAME="KEYWORDS" CONTENT="|">
myframeset.meta.description=the meta description

Another snippets reads the default values for meta description and meta keywords from a constant and you can override it by setting the values in the page type advanced

page.meta.DESCRIPTION = {$meta.description}
page.meta.DESCRIPTION.override.field = description
page.meta.KEYWORDS = {$meta.keywords}
page.meta.KEYWORDS.override.field = keywords

More information can be found on TSREF

TSREF PAGE Object

TSREF META