@JeremyECrawford Find Familiar during combat: " as an Action you can see through your familiar's eyes and hear what it hears "
Can I roll a Perception check? (or not because I've already use my Action?)
Do I roll it with the familiar's Perception modifier, or my own modifier?

— Draconis (@DerynDraconis) January 30, 2018

During combat, searching for something requires your action, whether you're using Investigation or Perception. You therefore can't take the Search action and use your familiar's eyes/ears on the same turn, unless you have an extra action from a feature like Action Surge. #DnD https://t.co/8agSiDiWPP

— Jeremy Crawford (@JeremyECrawford) January 30, 2018

@JeremyECrawford
What is the range for the catapult spell? The description in Xanathar says 90 ft, but the range says 60 ft. In EE the description also says 90, but the range says 150 ft. #DnD

— Carey Sauerbrun (@SauerCarey) December 21, 2017

The catapult spell lets you choose an object within the spell's range and then hurl that object a certain number of feet. The hurl distance is not the same as the range. (The spell's range has been updated in the EE Player's Guide.) #DnD https://t.co/QVgf2D8Qjl

— Jeremy Crawford (@JeremyECrawford) December 22, 2017

does the extra damage on an attack roll of 20 for Sword of Sharpness get doubled as well? IE, actually 8d6 since a 20 is also a crit? #dnd Where is the 4d6 coming from? That's not in the DMG.

— Jeremy Crawford (@JeremyECrawford) January 5, 2018

The srd from the WotC site has it at 4d6. Interesting. The DMG is the official source, not the SRD.

— Jeremy Crawford (@JeremyECrawford) January 5, 2018

@mikemearls @JeremyECrawford @matthewmercer Conjure Animals Initiative – If my initiative is 10, and I conjure animals who roll a 15 initiative, do they go on my turn or wait until the next round to start their attacks?

— Tyson Glaser (@TysonGlaser) December 14, 2017

When you cast conjure animals, you roll initiative for the summoned creatures, and they take their turns on their initiative, which has no relation to yours. #DnD https://t.co/AxxPjXIT7n

— Jeremy Crawford (@JeremyECrawford) December 14, 2017

Is it the same with Conjure Minor Elementals?

— The Delivery Guy (@Del_Guy) December 14, 2017

If a spell tells you to roll initiative for a creature you summon with that spell, the creature acts on its initiative, regardless of your initiative. Such spells include conjure animals and conjure elemental. #DnD https://t.co/OHutOImDkS

— Jeremy Crawford (@JeremyECrawford) December 14, 2017

So you'd hope for a roll lower than yours to get the summon to act earlier, or wait for the next round to add them to initiative?

— Jami (@DND_Jami) December 14, 2017

A spell that instructs you to roll initiative abides by the initiative rules, unless the spell's text says otherwise. For example, if it tells you to roll, and you roll a 15 for a creature you summon with the spell, the creature takes its turn on initiative count 15. #DnD https://t.co/pnesjNI6Pf

— Jeremy Crawford (@JeremyECrawford) December 14, 2017

What about this:

You’re init is 15. You summon on your turn and you roll a 14 for the creature’s init. Does it then move after you, or does it get added to init list at the end of the round? If you roll 14, they go at 14.

— Jeremy Crawford (@JeremyECrawford) December 14, 2017

Do you always roll initiative for summoned creatures though, or only if the spell instructs you to do so? For instance, do you roll initiative for the zombies/skeletons created by Danse Macabre or do they act on your initiative?

— DanDanFielding (@DMdandanfieldng) December 14, 2017

There are no general summoning rules. Regarding summoned creatures and initiative, it's actually redundant for a spell to tell you to roll initiative for a summoned creature, since the game's combat rules have you roll initiative for creatures in a combat. #DnD https://t.co/LuUfys0hjg

— Jeremy Crawford (@JeremyECrawford) December 14, 2017

Honestly, we never should have had spells tell you to roll initiative for creatures. The general rules just need a line that says, "If a creature joins a battle that's already in progress, roll initiative for the creature as normal."

— Jeremy Crawford (@JeremyECrawford) December 14, 2017

@JeremyECrawford
I have a question about the Geas spell in 5e. Can a creature effected by the spell disobey as much as they wish, but only get punished once a day, or they can only disobey once a day at the price of the damage, and the rest of the time must fulfill the command?

— Kailor Rangorn (@KailorRangorn) December 7, 2017

The geas spell deals its damage only once per day, no matter how often the target disobeys. #DnD https://t.co/txLRMTI8LB

— Jeremy Crawford (@JeremyECrawford) December 7, 2017

Can a spell with a range of "Self" be stored in a Ring of Spell Storing?

— Armando Doval (@armando_doval) January 3, 2018

When you store a spell in a ring of spell storing, you touch the ring, effectively ignoring the range specification of the spell. Later when you cast the spell from the ring, the spell's range becomes relevant. So yes, you can store a "Self" spell in the ring. #DnD https://t.co/iLJLMVXIx6

— Jeremy Crawford (@JeremyECrawford) January 3, 2018

@JeremyECrawford
This gets asked a lot but I’ve never seen a conclusive answer.
Does Undying Sentinel, the level 15 Oath of the Ancients paladin feature, prevent death from old age?
RAW it should, but there are some who argue otherwise. Please help put this issue to rest. pic.twitter.com/8MzrwIuhh8

— Henry Wall (@HenryWa01128026) December 8, 2017

The Undying Sentinel feature protects you from the drawbacks of old age, including dying of old age. You can still be killed, but not by the accumulation of years. #DnD https://t.co/brRivBxecd

— Jeremy Crawford (@JeremyECrawford) December 8, 2017

Thank you so much for your help, keep up the good work! ❤️ My pleasure!

— Jeremy Crawford (@JeremyECrawford) December 8, 2017