According to gswiki, AGI and DEX factor into evading standard maneuver rolls (https://gswiki.play.net/mediawiki/index.php/Creature_maneuver). It seems to have come from https://gswiki.play.net/mediawiki/index.php/Stronghold_Bowels_information_(saved_post), which discussed stone first specifically.

Has it ever been confirmed that both AGI and DEX matter against maneuvers in general? I'm trying to figure out how to best improve maneuver defenses - AGI enhancives, DEX enhancives, PF enhancives, or more perception ranks.