API:Watch

Token
To (un)watch a page, a token is required. This token is the same for all pages (and is not different for watch vs unwatch), but changes at every login. Watch/unwatch tokens can be obtained via action=tokens with type=watch (MW 1.20+), or by using the following method:

Watching and unwatching pages
Pages can be watched (added to your watchlist) and unwatched (removed from your watchlist) with action=watch. Of course, you can only add and remove pages to/from your own watchlist.

Parameters

 * : Page to (un)watch
 * : If set, unwatch the page. If not set, watch the page.
 * : Your (un)watch token.

Possible errors
Only the usual stuff.