@Mitch Dale, a fix was pushed for the JSON array issue. The Wrk Action can now output JSON arrays without throwing errors. As for the original question around if .tif/.tiff files can be accepted by Claude, it actually seems like Action can not accept TIFF. It can only accept the following: ['.gif', '.GIF', '.jpeg', '.JPEG', '.png', '.PNG', '.jpg', '.JPG', '.webp', '.WEBP', '.pdf', '.PDF']
In order to convert the format of your TIFF to an accepted format you must use "Convert image format"