This question relates to the SCAG errata regarding Booming Blade… does the monetary value of the component now negate being able to use your Pact of the Blade weapon or Shadow Blade in conjunction with Booming Blade?

— Baumer Goodtree (@BigBaumer) November 11, 2020

If a D&D warlock creates a weapon with Pact of the Blade, that weapon has the value indicated in chapter 5 of the Player's Handbook (the text of Pact of the Blade directs the reader to that chapter to choose the weapon).

Shadow blade, in contrast, weaves together gloom. #DnD https://t.co/aKwfyUduo3

— Jeremy Crawford (@JeremyECrawford) November 11, 2020

Don’t suppose you’re willing to explain the reasoning, here? The Pact of the Blade feature instructs you to pick a weapon from chapter 5 of the Player's Handbook. There you find the information for the weapon you chose, including its gp value, damage, weight, and properties.

— Jeremy Crawford (@JeremyECrawford) November 12, 2020

Also, what is the value of an Improvised Weapon in this regard? Is it based on the value of the object?

— Dave 🔂 (@Glistam) November 11, 2020

Items in D&D have the value specified for them in the "Equipment" chapter of the Player's Handbook. If an item doesn't appear there or in another rulebook, the DM determines that item's value, if any. #DnD https://t.co/KsrskTh5p6

— Jeremy Crawford (@JeremyECrawford) November 12, 2020

The Shadow Blade itself says “It counts as a simple melee weapon with which you are proficient.” All simple melee weapons are given a value as per Chapter 5 of the Player’s Handbook, and all those values allow it to work with the new version of Booming Blade.I can't stop finding ways to make it work, all RAW and supported by Jeremy's rulings (per the warlock pact weapon and improvised weapons).

— Dave 🔂 (@Glistam) November 12, 2020

As DM, I'd totally let the combo work. Shadow Blade creates a simple melee weapon, and if another rule cares about that weapon's value, I'd pick a value from the list of simple melee weapons in the Player's Handbook and apply that value ad hoc to the shadowy blade.

— Jeremy Crawford (@JeremyECrawford) November 12, 2020

Melee Cantrips used with Bladesinger Extra Attack? IE. cast, first atk with effect, second without?

@FullMthrlJckt @mikemearls
No. Extra Attack requires the Attack action, not the Cast a Spell action.

— Jeremy Crawford (@JeremyECrawford) October 29, 2015

@JeremyECrawford should spiritual weapon be concentration? Doesnt say in my phb its con or errata that I saw but gf9 spell card says yes

— Jeffery Mace (@sagechan1) July 5, 2015

The spiritual weapon spell doesn't require concentration. https://t.co/BOgiRTMYGx

— Jeremy Crawford (@JeremyECrawford) July 7, 2015