So I was thinking of a Shadrakai double boosting int single boosting dex (so starting with a 17 int, 14 Dex, 14 Con, and the rest are 10's after bonuses)

starting rogue for the skills then taking 3 levels of artificer 3 for armorer and infiltrator armor so you get the gemstone in the chest for lighting gun... which is technically a simple ranged weapon which I think means sneak attack  should work with it right?.    Then going straight rogue arcan trickster the rest of the way.   The first feat would be elven accuracy (boosting it) and I would be getting faerie fire as an artificer spell and then just blasting lightning sneak attack all the time.  

That would work right?

What feats etc should I focus on?  What other tips do you have for me

14 dex seems pretty low for a rogue. Since you seem to want to rely more on rogue features than other stuff, I would recommend swapping some things around so you have a +3 dex and +2 int. If you can, maybe just dump strength or something a lil bit to get +3 in both.

Quote from Quar1on >>

14 dex seems pretty low for a rogue. Since you seem to want to rely more on rogue features than other stuff, I would recommend swapping some things around so you have a +3 dex and +2 int. If you can, maybe just dump strength or something a lil bit to get +3 in both.

 The particular rogue is an arcane trickster who needs int for casting spells,  and when I attack with the lightning laucher I get to use int for attack and damage.   Rogue's sneak attack really power's up the lightning launcher because technically it's a simple ranged weapon rather than a spell.  Elven accuracy applies so as long as I have advantage I roll 3 times take the best.  Faerie fire guarantees that not only I but the whole party has advantage and the mind sharpener infusion ensures that I don't break concentration (if I fail a roll expend a charge).  When I need a nova attack use mage hand to stuff one bag of holding into another at a distance (and I recreate the bags of holding after my long rest which is 4 hours for the Shadrakai).  Rogue gets 4 skills, 4 skill expertise and reliable talent at rogue 11 (so use the attribute increase at rogue 12 to pick up skilled feat for 3 new skills.  Another feat I'm looking at is sharp shooter, so I'll be able to attack out to 300 feet without disadvantage).  When I get int to 20 that's +5 to attack and damage with the lightning launcher and since I'm only attacking once per round the lightning launcher is doing 2d6 instead of 1d6 which makes up for the 1 lost die of sneak attack damage.  Dex really isn't important to the build other than having enough to fill out the dex cap on a breastplate.   Breastplate because that way there's no disadvantage on stealth which means the infiltrator armor gives me advantage on stealth and the extra 5 feet of movement from the infiltrator armor plus cunning action plus the Shadrakai's teleport means he can get out of trouble.  Yeah he has a rapier with booming blade to lock down an opponent and then get away with cunning action disengage (or teleport out).  Which means most of the arcane trickster spells can be for utility.  Having magic missile prepared is a great concentration breaker for enemy spell casters.

Haven't figured out what to do with the rogue 16 attribute increase.  Might get resilient for con... but wondering if there's a feat out there that will let me make a ranged attack as an opportunity attack.

Also what are the rules on ranged attacks provoking opportunity attacks when you're not holding a ranged weapon and are holding a melee weapon (probably a rapier, probably a sentinel shield too).  Also looking at decanter of endless water.  To pick/break locks he can pour water in and freeze it with shape water. Thereby avoiding risking being jabbed with poisoned needles in trapped locks.

How many infusions do you think you get as a 3rd level artificer? Mind sharpener, two bags of holding, and a decanter of endless water?

As for ranged opportunity attacks, that's not something that gets provoked. One exception is the War Caster feat, which allows you to cast a spell as an opportunity attack. Of course, without the crossbow expert feat (or a reach weapon) a ranged attack would be made with disadvantage, and it would be a spell attack, so not really what you're looking for. If you have a Battle Master in your party, Commanding Strike has great synergy with rogues, but you shouldn't force a class onto somebody else just to help yourself.

Quote from EliasWindrider >>

Also what are the rules on ranged attacks provoking opportunity attacks when you're not holding a ranged weapon and are holding a melee weapon (probably a rapier, probably a sentinel shield too).  

 I have genuinely no clue what you are asking with this. Do you just mean the general rules for opportunity attacks?

Artificer can't make a decanter of endless water so that is a straight up magic item I'd want.  But you get 4 infusions at this level.

In some previous editions ranged attacks provoked aoo's I'm new to 5e, was asking if ranged attacks provoked aoo's in this edition and if it did does holding melee weapons prevent provoking.

You're looking at the wrong bit of the artificer table. Infusions Known is how many you know, not how many you can have at once. You want to look at Infused Items, which is limited to 2 at 3rd level.

The only way to really make an opportunity attack with a ranged weapon is the Commander's Strike maneuver (from Battle Master fighter subclass, a feat, or a fighting style). Commander's Strike generally has great synergy with rogues, on account of Sneak Attack being once per turn instead of once per round.

Are you asking if holding a melee weapon means you can't provoke opportunity attacks? If so, the answer is of course you can make opportunity attacks with melee weapons. Why wouldn't you be able to? If you are asking if you can get an opportunity attack with a melee weapon, switch to a ranged weapon, and then make the opportunity attack with the ranged weapon, then the answer is a very hard no.

Ranged attacks do not provoke opportunity attacks from adjacent enemies. In 5e the penalty is that your ranged attacks are made with disadvantage when you have a hostile creature adjacent to you.

This is a decent build, and certainly can be fun to roleplay. Mechanics-wise, it's kind of jumping through a lot of hoops to do the things a rogue can do anyway except with INT, and the issue there is that DEX is just a stronger stat in 5e overall, contributing to initiative, cheaper armor, the most rogue-y skills, and a very important saving throw. So there's lots of little things you lose by shifting from DEX primary to INT primary, in addition to the lost rogue levels. But you do gain some fun infusions and a handless ranged weapon, and again I think it could be a fun concept to play, so I hope you enjoy it!

Thanks for setting me straight on the rules.

Would dropping more levels of rogue for 2 chronurgy wizard be a good trade? It'd let me add dex and int to initiative, and the twice per long rest trigger rerolls as a reaction.

Adding intelligence to initiative doesn't matter a whole lot unless you're an assassin, and even then it's not super valuable. I would recommend not doing that.