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

 * : Single page to (un)watch (for backwards compatibility)
 * : List of one or more pages to (un)watch
 * : If set, unwatches all pages in bulk. This can be useful for some situations with prolific accounts that have accidentally overfilled their watchlists and have trouble managing it. Can only be used along with  parameter. Since 1.24
 * : If set, unwatch the page. If not set, watch the page.
 * : Your (un)watch token.

Possible errors
Only the usual stuff.