Quote Originally Posted by the_tick_rules View Post
Not that good. It makes you immune to non-magical weapons. Against non-magical weapons or missiles you get a reflex save for half damage. It has no function against spells and since it specifically says weapons I would say it doesn't function against falling rocks, dragon breath etc. I'm also not entirely sure on the idea that it stacks with evasion. Evasion specifically says against an attack that deals half damage on a successful save. Weapon attacks don't have a normal reflex save for half.
Nope, you're immune to non-magical weapons, and get a save(that you auto) against MAGIC weapons. It's 200,000(+25,000 for a Ring of Evasion) to be immune to all melee attacks.
Spoiler: Item Text
Show
Starmantle Cloak: This draping black cloak turns into a sparkling mantle of tiny, cascading stars when worn. The cloak sheds light as a torch, renders the wearer impervious to nonmagical weapon attacks, and transforms any nonmagical weapon or missile that strikes the wearer into harmless light, destroying it. Contact with the starmantle does not destroy magic weapons or missiles, but the starmantle’s wearer is entitled to a DC 15 Reflex save each time he is struck by such a weapon; success indicates that the wearer takes only half damage from the attack

As for evasion, the normal situation for a character with a Starmantle Cloak is that she receives half damage from melee attacks. Evasion even references "Attacks" rather than "spells".
Spoiler: Evasion Text
Show
At 2nd level and higher, a rogue can avoid even magical and unusual attacks with great agility. If she makes a successful Reflex saving throw against an attack that normally deals half damage on a successful save, she instead takes no damage. Evasion can be used only if the rogue is wearing light armor or no armor. A helpless rogue does not gain the benefit of evasion.