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Duncan_Ruadrik
2010-08-30, 04:13 AM
Okay, heres the deal...

I have a rogue in the party Im Dming for. He wants Darkvision. He has Use Magic Device. He also has enough money to buy a scroll of Darkvision (150 gp) and a scroll of Permanency (3,375 gp) included in the cost for the scroll of Permanency is the 500 xp necessary to make darkvision permanent. Right? or did I get something wrong...

Also, can one take 20 on a UMD for scrolls? I understand that you cannot take 10, and cannot take 20 on rolls for blindly activating an item, since that has a negative consequence. (a magical mishap)

However, if I read this correctly, a scroll has no negative consequence. (such as falling in the chasm, blowing yourself up etc.) You just dont cast the spell, though the spell is still there, scribed on the scroll, until you cast it. Assuming you can roll high enough to use it.... i.e. taking 20?

Thanks in advance for the help everyone!

Nidogg
2010-08-30, 04:19 AM
nah you cant take 20 or 10 on UMD because of the scroll mishap rules. but otherwise the plan is sound.

Tyrmatt
2010-08-30, 04:26 AM
Only warlocks can take 10 on UMD. Four levels needed to give you this ability.

To be fair though, any party rogue worth his gold probably has numerous ranks in UMD anyhow.

Duncan_Ruadrik
2010-08-30, 04:37 AM
he has max ranks.... but the caster level of the permanency is 11.... so 20+11=33. He needs to beat a DC of 33, and hes level 3, a UMD of... +6? I believe. He worked it out, where, in another 2 or 3 levels and 5 ranks in Decipher Script (for UMD while using scroll synergy) he could pull it off.... but only if he rolled a 20.

So there are mishaps for scrolls? I must have missed that in the DMG.... bleh. literacy. its too hard sometimes.

Reynard
2010-08-30, 04:40 AM
No, not even if he rolled a twenty.

By RAW, there are no critical successes (or failures) on skill checks.

BladeofOblivion
2010-08-30, 04:44 AM
Permanency scroll abuse is officially the most fun thing to do as a Warlock.

1. Get ten of 'em
2. Pay the local Wizard for some buffs
3. ???
4. Profit!

Bayar
2010-08-30, 04:45 AM
Only Warlocks and Artificiers can take 10 on UMD. Four levels needed to give you this ability.

To be fair though, any party rogue worth his gold probably has numerous ranks in UMD anyhow.

Edited your message a bit for accuracy.

Curmudgeon
2010-08-30, 05:14 AM
Edited your message a bit for accuracy.
Always better to combine a statement like that with correct spelling:

That's Artificers, not Artificiers.

Soren Hero
2010-08-30, 06:01 AM
would the rogues level 10 special ability "skill mastery" be of any use in this scenario? it says you are allowed to take ten on 3+Int mod skills, but specifically mentions "stress and distractions", not mishaps..this might not be of any help to the op, because they would have to be a level 10 rogue...but now i just wanna know

Kaww
2010-08-30, 06:31 AM
Permanency scroll abuse is officially the most fun thing to do as a Warlock.

1. Get ten of 'em
2. Pay the local Wizard for some buffs
3. ???
4. Profit!

I'm sorry but I think this is the spell description...


You cast the desired spell and then follow
it with the permanency spell.

PHB 260

Not sure if the xp cost is calculated within the scroll cost (I'm pretty sure it isn't). There are different xp costs to pay...

And if it is should you cont it as xp-gp ratio for magic items (25:1) or BoED xp-gp ratio (5:1)?

Curmudgeon
2010-08-30, 08:23 AM
Not sure if the xp cost is calculated within the scroll cost (I'm pretty sure it isn't).
I'm pretty sure you're wrong about that. Check Dungeon Master's Guide page 240, and you'll see a footnote for a scroll of Permanency:
1 Includes experience point cost up to 2,000 XP. You can, of course, get someone to craft such a scroll with a different XP cost included.

Tharck
2010-08-30, 08:51 AM
he has max ranks.... but the caster level of the permanency is 11.... so 20+11=33. He needs to beat a DC of 33, and hes level 3, a UMD of... +6? I believe. He worked it out, where, in another 2 or 3 levels and 5 ranks in Decipher Script (for UMD while using scroll synergy) he could pull it off.... but only if he rolled a 20.

So there are mishaps for scrolls? I must have missed that in the DMG.... bleh. literacy. its too hard sometimes.

Dont forget to either purchase, or have cast on you Eagle's Splendor for +4 CHA and another +2 to your check.

Tyndmyr
2010-08-30, 08:57 AM
Assuming only a ten in cha, at level 6, he could have +9 from ranks, +4 from synergy(if he really tries) to scrolls, +3 from skill focus(not a bad use, actually), +2 from a mw item, and +2 from the aforementioned cha buff. Total of +20, meaning he only needs to roll a 13. Since there's no mishaps to worry about, he could just attempt till he gets lucky.

Kaww
2010-08-30, 09:03 AM
I'm pretty sure you're wrong about that. Check Dungeon Master's Guide page 240, and you'll see a footnote for a scroll of Permanency:

I stand corrected.

Didn't think they'd make it like that. Although the price here is not price listed for a permanency scroll. The price is 10,125 gp (also DMG 240). And that is ok for a scroll with xp cost paid...

Killer Angel
2010-08-30, 09:14 AM
would the rogues level 10 special ability "skill mastery" be of any use in this scenario? it says you are allowed to take ten on 3+Int mod skills, but specifically mentions "stress and distractions", not mishaps..this might not be of any help to the op, because they would have to be a level 10 rogue...but now i just wanna know

You can't



Special
You cannot take 10 with this skill.


It's not a matter of stress and distraction. You simply cannot take 10.

Swok
2010-08-30, 09:36 AM
You can't



It's not a matter of stress and distraction. You simply cannot take 10.

Must really suck to be a Warlock or an Artificer then.

Fax Celestis
2010-08-30, 09:47 AM
scroll of Darkvision (150 gp) and a scroll of Permanency (3,375 gp) included in the cost for the scroll of Permanency is the 500 xp

...why are you buying scrolls and using permanency? It'll only last until someone smacks him with a dispel magic, and then all this effort will be wasted.

Goggles of ebon eyes, crafted with the item creation rules, cost Spell Level * Caster Level * 2000 * duration modifier, or 1*1*2000*1.5, for 3000gp all told. If you get hit with a dispel, it shuts off for 1d4 rounds instead of disappearing, and it lets you see in magical darkness too. Ebon Eyes is in the Spell Compendium.

Even if you were to get goggles of darkvision, it'd be SL*CL*2000 for 2*3*2000 or 12000gp, which is more expensive but still would be resistant to dispel magic.

Killer Angel
2010-08-30, 09:50 AM
Must really suck to be a Warlock or an Artificer then.

:smallannoyed:
The fact that we were discussing rogue and specifically Rogue's Skill Mastery, maybe was relevant?
Warlocks and Artificier were already covered by Tyrmat and Bayar. Specific trumps general.

But, if you prefere...
EDIT:

It's not a matter of stress and distraction. You simply cannot take 10 (unless you have a specific ability that trumps the skill's description and let you take it).
:smallamused:

Greenish
2010-08-30, 09:52 AM
No, not even if he rolled a twenty.

By RAW, there are no critical successes (or failures) on skill checks.He's not referring to a critical success, but to having just enough ranks to succeed by rolling 20.

A level 6 rogue with 10 cha: 9 (ranks) + 2 (synergy from decipher script) + 2 (cha from Eagle's Splendor) = +13 modifier.

The DC being 33, he'd succeed on a natural 20.

Swok
2010-08-30, 10:09 AM
:smallannoyed:
. Specific trumps general.

That was my point, along with "If skill mastery doesn't work for it, neither do these other classes class features that let them take 10 on UMD."

Seriously, the text of the classes that specifically grant taking 10 with UMD is identical to Skill Mastery (at least in terms of saying "even while distracted or under adverse conditions). If it doesn't work for rogues, it doesn't work for them.

Jolly
2010-08-30, 10:16 AM
...why are you buying scrolls and using permanency? It'll only last until someone smacks him with a dispel magic, and then all this effort will be wasted.
[/I]

Huh? Maybe I'm not understanding Permanency (or Dispel Magic for that matter) but my understanding was that once you had a spell made permanent it was not an effect that is removable, but a character trait. Is that wrong?

Also, ditch Darkvision for True Seeing, and pay a higher level rogue to cast off the scrolls for you.

Greenish
2010-08-30, 10:22 AM
Huh? Maybe I'm not understanding Permanency (or Dispel Magic for that matter) but my understanding was that once you had a spell made permanent it was not an effect that is removable, but a character trait. Is that wrong?The spell states that "spells cast on other creatures, objects, or locations (not on you) are vulnerable to dispel magic as normal".

mcl01
2010-08-30, 10:23 AM
According to the SRD...

Permanent: The energy remains as long as the effect does. This means the spell is vulnerable to dispel magic.

Permanency merely increases the duration to permanent, not instantaneous. The magic has to remain for the effect to occur. This means the magic itself has an infinite duration, but the magic can still be removed through non-duration means (i.e. dispel).

Compare to instantaneous where the effect is created instantaneously, and the magic disappears while the effect remains. I.e. if you cast mending, the magic repairs the object, and then the magic disappears, leaving the object repaired. If they try to dispel, there's no magic for it to dispel.

Greenish
2010-08-30, 10:27 AM
The spell states that "spells cast on other creatures, objects, or locations (not on you) are vulnerable to dispel magic as normal".Oopsie daisy, the relevant rule was "This application of permanency can be dispelled only by a caster of higher level than you were when you cast the spell."

Killer Angel
2010-08-30, 10:38 AM
That was my point, along with "If skill mastery doesn't work for it, neither do these other classes class features that let them take 10 on UMD."

Seriously, the text of the classes that specifically grant taking 10 with UMD is identical to Skill Mastery (at least in terms of saying "even while distracted or under adverse conditions). If it doesn't work for rogues, it doesn't work for them.

mmm...
I don't have at hand the exact wording of Warlock's ability, but, staying on Skill Mastery:

The general is:
When your character is not being threatened or distracted, you may choose to take 10 on a skill.
We have a serie of skills on which you cannot take 10, 'cause threatening / distraction are involved (tumble, etc).

Specific:
Skill Mastery let you take 10 even if stress and distractions would normally prevent you from doing so.

BUT, all the skills that usually don't let you take 10, in their description don't have nothing on the subject, the only exception is UMD, that explicitly says: "Special: You cannot take 10 with this skill". Nothing regardin' distraction or other things.

So, it appears that UMD, is even more specific regardin the "take 10" than Skill Mastery.

So, unless you have an ability that explicitly tells that you can take 10 on UMD, I don't think you can.


EDIT: Further elaboration from EN World forum.

Skill Mastery allows you to take 10 "even if stress and distractions would normally prevent her from doing so", it does not state that you can bypass a restriction in the skill itself, only the conditional restriction.
Certain class abilities allow you to take 10 on UMD. The bard's jack-of-all-trades specifically says it's allowed to work even with skills where taking 10 isn't allowed. The rogue's skill mastery has no such provision.

Jolly
2010-08-30, 10:53 AM
Wow, Permanency now wins the award for most useless spell ever. That'd be Rule 0'ed in one of my campaigns so fast your head would spin.

Snake-Aes
2010-08-30, 10:56 AM
Wow, Permanency now wins the award for most useless spell ever. That'd be Rule 0'ed in one of my campaigns so fast your head would spin.

It's not useless, you just can't expect it to solve all your buff problems. It is still useful if it is being placed somewhere dispelling isn't a biggie. It still spares you having to cast a few buffs everyday, releasing those slots for more useful spells until the previous buffs are dispelled and so on.

Kaww
2010-08-30, 11:35 AM
Still, generally not worth the xp price...

And most low level can be compensated via items. Cheep ones too...

They use item slots, but nothing worth having comes free.

Curmudgeon
2010-08-30, 11:37 AM
Wow, Permanency now wins the award for most useless spell ever.
People go gaga over Divine Metamagic (Persistent Spell), which merely extends spells to 24 hour duration and thus uses up resources every day. Permanency makes spells last longer than that and doesn't require you to acquire 3-4 feats. It's hardly useless.

Fax Celestis
2010-08-30, 11:40 AM
People go gaga over Divine Metamagic (Persistent Spell), which merely extends spells to 24 hour duration and thus uses up resources every day. Permanency makes spells last longer than that and doesn't require you to acquire 3-4 feats. It's hardly useless.

Persistent Spell works with a lot more spells than permanency does.

Kaww
2010-08-30, 11:42 AM
People go gaga over Divine Metamagic (Persistent Spell), which merely extends spells to 24 hour duration and thus uses up resources every day. Permanency makes spells last longer than that and doesn't require you to acquire 3-4 feats. It's hardly useless.

True, but it has a really limited spell selection. And you can't make any paradoxes with it, while DMM can do really silly things...

Tyger
2010-08-30, 11:45 AM
People go gaga over Divine Metamagic (Persistent Spell), which merely extends spells to 24 hour duration and thus uses up resources every day. Permanency makes spells last longer than that and doesn't require you to acquire 3-4 feats. It's hardly useless.


Persistent Spell works with a lot more spells than permanency does.

And doesn't take any XP. Your turn attempts come back tomorrow with no effort on your part. Your XP, not so much.

But yeah, Permanency is far from useless, its just not the answer to every single duration problem that exists.

ericgrau
2010-08-30, 11:49 AM
UMD is the only skill where you can fail on a natural 1. The result is that you need to wait 24 hours before trying again. Don't you love exceptions like that? >_<

Ya, the plan is sound. The reason someone might do this and eat the xp / gold cost on something vunerable to dispel is that goggles of the night cost 12,000 gp. Even if you are dispelled once you may still come out ahead. Plus whenever you're a level behind you gain xp faster, so you can start recovering your losses. First thing to ask is how many times you've been dispelled in a campaign, remembering only half of those are successful. So permanency stays useful, just not abusable. Which is great. If they lasted forever then you could eventually regain the lost xp through the faster xp gain and get free power. That's bad. If anything I might give an xp discount to encourage more permanencies in the world, but that's it.

Kaww
2010-08-30, 11:58 AM
UMD is the only skill where you can fail on a natural 1. The result is that you need to wait 24 hours before trying again. Don't you love exceptions like that? >_<

Ya, the plan is sound. The reason someone might do this and eat the xp / gold cost on something vunerable to dispel is that goggles of the night cost 12,000 gp. Even if you are dispelled once you may still come out ahead. Plus whenever you're a level behind you gain xp faster, so you can start recovering your losses. First thing to ask is how many times you've been dispelled in a campaign, remembering only half of those are successful. So permanency stays useful, just not abusable. Which is great. If they lasted forever then you could eventually regain the lost xp through the faster xp gain and get free power. That's bad. If anything I might give an xp discount to encourage more permanencies in the world, but that's it.

You can't recover all the xp you lost this way. Only some percent, and this depends on the way DM gives xp. I'd go with magic items every time... GP is usually more easy to gain the xp.

Jolly
2010-08-30, 12:13 PM
I still just can't see paying XP for an easily removable buff. But, that's just me and the campaigns and DM's I'm used to. I think calling a Permanency that's actually, you know, Permanent an abuse is kind of silly, however.

Tharck
2010-08-30, 12:36 PM
Permanency is a solid spell.

Some campaings money is a more limited resource than XP.
In campaigns where money is excessive then spending some money on a scroll for permanency is a good option since all of your item slots are and likely should be filled. Also buying a CL 40 Permanency is a nice touch. As for rolling a rogue without darkvision - luls. L2 Gnome.

Other campaigns it might be quite the opposite. It's a spell, not the best, but solid.

Tyndmyr
2010-08-30, 12:44 PM
UMD is the only skill where you can fail on a natural 1. The result is that you need to wait 24 hours before trying again. Don't you love exceptions like that? >_<

Ya, the plan is sound. The reason someone might do this and eat the xp / gold cost on something vunerable to dispel is that goggles of the night cost 12,000 gp. Even if you are dispelled once you may still come out ahead. Plus whenever you're a level behind you gain xp faster, so you can start recovering your losses. First thing to ask is how many times you've been dispelled in a campaign, remembering only half of those are successful. So permanency stays useful, just not abusable. Which is great. If they lasted forever then you could eventually regain the lost xp through the faster xp gain and get free power. That's bad. If anything I might give an xp discount to encourage more permanencies in the world, but that's it.

In addition to all that, there's the fact that you still have a slot free. Given how many nifty, inexpensive magic items exist, that's a nice bonus.

Personally, I love permanency, and use it on every buff I'll always want up. Detect Magic? Yes please. See invisibility? Definitely. Darkvision? Absolutely.

Resistance I generally skip, due to availability of cloaks, and the fact that I normally ignore the cloak slot, but if I ever found a must-have item for that, I'd permanency the resistance line too.

As always, I advocate a ring of counterspelling, charged with dispel magic. 4000 gold to protect your permanencies is remarkably cheap. For the paranoid, blow 100g on a casting of craft magic tattoo beforehand for +1 CL to make the dispels slightly harder.

Curmudgeon
2010-08-30, 01:39 PM
UMD is the only skill where you can fail on a natural 1.
Yeah, that's wrong. Any skill where you don't have enough ranks to always succeed can result in a failed check with a poor roll.

Try Again: Yes, but if you ever roll a natural 1 while attempting to activate an item and you fail, then you can’t try to activate that item again for 24 hours. A natural 1 isn't a guaranteed failure, any more than it is for any other skill check. It just has additional consequences if your failure happens to involve a rolled (natural) 1.

Duncan_Ruadrik
2010-08-30, 04:00 PM
okay, so...

1.)Permanent is not permanent, it is subject to dispelling.

2.)Cannot take 20 on UMD.

3.)However, it is possible, by level 6, to do this with a reasonable chance of success.

Got this all right?

The scroll price i listed, includes the gp price for 500xp, not the full 2000xp that the price of the permanency scroll is combined with in the DMG. that is why there is a price disparity. The player didnt need 2000xp, only 500xp. so he paid accordingly.

seeing as this can be dispelled (undesirable) is there another cheap way to do this? I generally do not hand out gold to my players, but rather items, which are generally useful to at least one person in the party. Maybe, 5000gp or less? the goggles are too expensive for this level...

Ashiel
2010-08-30, 05:52 PM
okay, so...

1.)Permanent is not permanent, it is subject to dispelling.

2.)Cannot take 20 on UMD.

3.)However, it is possible, by level 6, to do this with a reasonable chance of success.

Got this all right?

The scroll price i listed, includes the gp price for 500xp, not the full 2000xp that the price of the permanency scroll is combined with in the DMG. that is why there is a price disparity. The player didnt need 2000xp, only 500xp. so he paid accordingly.

seeing as this can be dispelled (undesirable) is there another cheap way to do this? I generally do not hand out gold to my players, but rather items, which are generally useful to at least one person in the party. Maybe, 5000gp or less? the goggles are too expensive for this level...

The DMG tells you the price for an x/day wand. This would be a reasonable alternative to a permanent spell or a continuous use magic item; and it is very useful for rogues with UMD since the DC to use a spell from a spell-trigger item is 20.

Taken strait from the magic item creation charts, wands and staffs are 50 charge spell trigger items. It says if you want to create one with charges per day, you instead take the normal cost of the item, then divide it by (5 divided by the charges per day); so a wand with 1 charge per day would be 1/5th the price of a 50 charge wand, a 5/day would be the same cost, and a 10/day would be double the cost.

Now, before anyone adds, I know they came in an introduced "eternal wands" in later books which are not priced this way - but such wands can be used by anyone who can cast arcane spells last I checked, so they don't work like wands anyway.

This is just using core guidelines, and I find it works great. My players often will pickup wands with a few charges per day of little things. An x/day wand of magic weapon is a fair alternative to an actual magic weapon at low levels, for example (and a paladin, rogue, sorcerer, wizard, cleric, and bard can all use it without much fuss).

Curmudgeon
2010-08-30, 06:49 PM
The DMG tells you the price for an x/day wand.
...
Taken strait from the magic item creation charts, wands and staffs are 50 charge spell trigger items. It says if you want to create one with charges per day, you instead take the normal cost of the item, then divide it by (5 divided by the charges per day)
That's definitely not what the DMG tells you. You're skipping the primary rule for custom item pricing (a comparable existing item), and going right to the "otherwise" clause. Ignoring rules is what causes people to throw around names like "munchkin".

Now, before anyone adds, I know they came in an introduced "eternal wands" in later books which are not priced this way
... and here we have the existing items that should be used to set such prices, by the primary rule stated in the DMG.

Binks
2010-08-30, 08:04 PM
You can't recover all the xp you lost this way. Only some percent, and this depends on the way DM gives xp. I'd go with magic items every time... GP is usually more easy to gain the xp.

XP is a River. (http://community.wizards.com/go/thread/view/75882/19872242/Experience_is_a_River) If your GM is using your actual level as the determining factor for your xp then (up to a certain point) xp is cheaper than gold.

The rogue wants to spend 3525gp to have a magic buff like a 12000gp item? That's perfectly reasonable, and unless you get dispelled 3 times you come out ahead on the price.

However he can't take 20. He can roll repeatedly and hope that he rolls 20 before he rolls 1, but if he hits that 1 before he hits a 20 he can't try again for 24h, which means he'll have to buy the darkvision scroll again, which means there's a risk and penalty to failure, so no taking 20.

If you want to houserule it and let him take 20 though there'd be nothing wrong with that, he's essentially paying a lower price for an effect but risking it being dispelled.

Ashiel
2010-08-30, 09:09 PM
That's definitely not what the DMG tells you. You're skipping the primary rule for custom item pricing (a comparable existing item), and going right to the "otherwise" clause. Ignoring rules is what causes people to throw around names like "munchkin".

... and here we have the existing items that should be used to set such prices, by the primary rule stated in the DMG.

As noted previously, eternal wands do not follow the same rules that normal wands do. One of the main things with eternal wands being that they may be used by anyone who casts arcane spells; allowing classes such as the Magewright NPC class to make use of expanded spell lists.

The "comparable item" is in fact wands and staffs. They are the only default spell-trigger items in the game, and likewise the most common charged items. The DMG says if it is charged per day you divide the base cost of the item as appropriate; so in the case of an x/day spell-trigger item then that is what you do.

Comparatively, the boots of teleportation (priced at 49,000gp) are usable by anyone and apparently use the command word price mulitplier, as opposed to the "continuous or use activated", coming out using the guidelines as a little above 50,000gp (so the boots are a bit underpriced).

So if we have a wand of magic weapon, caster level 1 (one hour), once per day, then the wand will cost 150gp market value and require the spell-trigger or a DC 20 UMD check. Alternatively, a "command word" version of the same would cost 360gp, or 400gp for a use activated item.

So you can hold off on throwin' around "munchkin".

Swok
2010-08-30, 11:13 PM
mmm...
I don't have at hand the exact wording of Warlock's ability, but, staying on Skill Mastery:

The general is:
When your character is not being threatened or distracted, you may choose to take 10 on a skill.
We have a serie of skills on which you cannot take 10, 'cause threatening / distraction are involved (tumble, etc).

Specific:
Skill Mastery let you take 10 even if stress and distractions would normally prevent you from doing so.

BUT, all the skills that usually don't let you take 10, in their description don't have nothing on the subject, the only exception is UMD, that explicitly says: "Special: You cannot take 10 with this skill". Nothing regardin' distraction or other things.

So, it appears that UMD, is even more specific regardin the "take 10" than Skill Mastery.

So, unless you have an ability that explicitly tells that you can take 10 on UMD, I don't think you can.


EDIT: Further elaboration from EN World forum.

Skill Mastery allows you to take 10 "even if stress and distractions would normally prevent her from doing so", it does not state that you can bypass a restriction in the skill itself, only the conditional restriction.
Certain class abilities allow you to take 10 on UMD. The bard's jack-of-all-trades specifically says it's allowed to work even with skills where taking 10 isn't allowed. The rogue's skill mastery has no such provision.

Unless it was errata'd, Deceive Item states "When making a Use Magic
Device check, a warlock can take 10 even if distracted or
threatened."

Nothing about bypassing the "cannot take ten" bit of the skill. All it states is a warlock can take ten on the skill even while distracted or threatened, exactly like skill mastery says for chosen skills.

Killer Angel
2010-08-31, 04:39 AM
Unless it was errata'd, Deceive Item states "When making a Use Magic
Device check, a warlock can take 10 even if distracted or
threatened."

Nothing about bypassing the "cannot take ten" bit of the skill. All it states is a warlock can take ten on the skill even while distracted or threatened, exactly like skill mastery says for chosen skills.

Deceive Item explicitly states UMD, while Skill Mastery doesn't.
Anyway, the official ruling:


Can a rogue with skill mastery take 10 on a Use Magic Device check?
No. The rogue’s skill mastery class feature states that “she
can take 10 even if stress and distractions would normally
prevent her from doing so.” This only applies to skills that
allow a character to take 10 in nonstressful situations; if a skill
simply doesn’t allow a character to take 10 under any
circumstances (such as Use Magic Device), skill mastery
provides no benefit.


The warlock’s deceive item class feature (CAr 8) allows him to take 10 on Use Magic Device checks “even if
distracted or threatened,” but the Use Magic Device skill
says you can’t ever take 10, regardless of distraction. Does
deceive item also let the warlock ignore this restriction?
This class feature really does two things. First, it allows the
warlock to take 10 on Use Magic Device skill checks (a boon
all by itself). Second, it allows him to take 10 on such checks
even in conditions where that would normally not be possible.

So yeah, Walocks (and artificiers) can take 10 on UMD, a rogue with Skill Mastery can't.