Need some help with Automator/AppleScript

Do you want/need the script to reload the current page? or load it from scratch?

Your post states 'refresh a page that I've left open', which implies you've already passed the login/captcha process. Does reloading the page require another login/captcha or will the existing login credentials still work?

That's important because it changes the script from trivial (already logged in) to almost impossible (process the login/captcha form).

So if it's just a matter of reloading the current page, that's easy:

tell application "Safari"

do JavaScript "window.location.reload()" in tab 1 of window 1

end tell

You might need to better reference which tab/window you want to reload because 'tab 1 of window 1' will always point to the front document, even if that's not the one you want to reload (e.g. you've opened another browser window). It's possible to get around that, but before going down that path it would be useful to know if that's going to meet your needs, or whether you do need to re-login or pass the captcha.

Then this should get you started. It grabs the URL of the current window and then repeatedly reloads it, looking for the specified keyword. You'll need to determine the actions to take when/if the keyword exists or doesn't.

set keyword to "blah"

tell application "Safari"

-- get the current window

set myWindow to (get current tab of window 1)

repeat

do JavaScript "window.location.reload()" in myWindow

-- wait for the page to load

repeat until ((do JavaScript "document.readyState;" in myWindow) is equal to "complete")

delay 0.5

end repeat

set pageContent to text of myWindow

if pageContent contains keyword then

-- code here for 'situation normal'

else

-- code here for when text is missing

end if

delay 2 -- wait a bit before running again

end repeat

end tell

Since it stores a reference to the window you're free to do other things (open new windows, switch apps, etc.) as long as you don't close this window.