True Strike, Innate Sorcery, and magic items.

The dnd5.5 version of True Strike is a spell lets you make a weapon attack (Magic Action, NOT Attack Action).

The spell reads in part: "you make one attack with the weapon used in the spell’s casting. The attack uses your spellcasting ability for the attack and damage rolls instead of using Strength or Dexterity"

Now this brings me to my question: Does this count as a spell attack? If so, a sorcerer could do this attack with advantage (with innate sorcery), and if they have a magic item that adds a bonus to spell attacks (such as Robe of the Archmagi), could add this to the attack roll.

But hold on; the spell says you are making an attack with the weapon. Does this count as a weapons attack? If so, a magic weapon (+1, +2, +3) could provide an additional to hit bonus.

This feels like double dipping, especially because then a staff of power would effectively have +4 to hit.

TLDR: Is True Strike a spell attack, weapons attack, or both?

True Strike is an attack with a weapon, so I'd say that is a weapon attack but there is only a very few cases where that probably matters. One case would be a Wand of the War Mage; You don't get to double dip with a +2 Rapier and a +2 Wand of the War Mage in this scenario. 

True strike does NOT say to take a Magic Action to cast but does say ...used in the spell's casting...

It DOES say you make one attack so there is not multi-Attacks

Quote from Marc_Ducorsky >>

True strike does NOT say to take a Magic Action to cast but does say ...used in the spell's casting...

It DOES say you make one attack so there is not multi-Attacks

 As far as I remember, no spell says it takes the Magic Action but rather the Magic Action is taken when casting a spell with a casting time of 1 action, using an action.

As such no spell with a casting time of 1 action necessarily requires the Magic Action, which is important when remembering Sorcerer's Quicken Spell Metamagic or Eldritch Knight's (Improved) War Magic as two examples of casting spells with a casting time of 1 action but do not actually take the Magic Action to cast them.

Its a weapon attack.

Other melee cantrips (chill touch,,thornwhip, shocking grasp) specifically call out "make a melee SPELL ATTACK" as part of the spells description.  True strike contains no such language. It only allows you to swap modifiers.  

The spell should have been written more ike shillelagh, but instead they made it a magic action casting combined with the attack action to double dip on action economy.  It is confusing but its definately a weapon attack.  Magical weapon bonuses to hit or damage apply but any additional spell attack modifiers to hit and damage do not. 

I read True Strike to mean that you enchant your weapon with the spell, then make a weapon attack. The spell's target is self, so the spell itself does not have an attack roll - you just get the extra benefit of getting to make a weapon attack right afterwards.

There's this Sage Advice Compendium question involving True Strike that may help;

Can you use True Strike with Extra Attack, Opportunity Attack, Sneak Attack, and other weapon attack options?

True Strike doesn’t work with Extra Attack or any other feature that requires the Attack action. Like other spells with a casting time of an action, casting True Strike requires you to take the Magic action, not the Attack action. Similarly, unless a special feature allows you to do so, you can’t cast True Strike when making an Opportunity Attack.

However, an attack made as part of True Strike works with Sneak Attack so long as it fills the normal requirements for that feature. For example, if you have the Sneak Attack feature and cast True Strike with a Finesse weapon, you can deal Sneak Attack damage to the target of the attack if you have Advantage on the attack roll and hit.

(this is just how I see it, but please note that I'm not trying to convince anyone, I'm just sharing my opinion. The topic was broadly discussed in the Rules & Game Mechanics subforum)

To me, True Strike counts as a weapon attack for different reasons:

- The wording of the spell overrides the general rule for a Spell Attack:

Guided by a flash of magical insight, you make one attack with the weapon used in the spell’s casting. The attack uses your spellcasting ability for the attack and damage rolls instead of using Strength or Dexterity. [...]

And that text in blue is indeed the definition of a Weapon Attack: "A weapon attack is an attack roll made with a weapon."

- When a spell requires a "spell attack", it is explicitly stated (e.g. Chill Touch, Guiding Bolt, Fire Bolt, Shocking Grasp, Sorcerous Burst, or Spiritual Weapon). Sorcerous Burst originally didn't include this, but it was corrected via errata. For comparison, Swift Quiver is a good example: it doesn't include spell attacks, just weapon attacks.

- If True Strike were a spell attack, why specify that use your spellcasting ability modifier for the attack roll? All spell attacks behave that way by default.

- Requiring a weapon you're proficient with for the Material component is also a reason for me.

- The wording for True Strike is very similar to Booming Blade and Green-Flame Blade. If you compare the SAC previously quoted by Plaguescarred with the next two answers about BB and GFB, the relationship between the three becomes clear. I highlighted some parts about the attack type and related to the explanations above.

How do I know which ability modifier to use with an attack roll and its damage roll?

[...] What about unusual cases like the green-flame blade spell? The spell, which appears in the Sword Coast Adventurer’s Guide, tells you to make a melee attack with a weapon. Look at the table above, and you see that, under normal circumstances, you use your Strength modifier when you make a melee weapon attack. It doesn’t matter that a spell told you to attack. If a spell expects you to make a spell attack, the spell’s description says so. For examples, take a look at fire bolt and ray of frost. Both say it—“spell attack.”

Can you use green-flame blade and booming blade with Extra Attack, opportunity attacks, Sneak Attack, and other weapon attack options?

Introduced in the Sword Coast Adventurer’s Guide , the green-flame blade and booming blade spells pose a number of questions, because they each do something unusual: require you to make a melee attack with a weapon as part of the spell’s casting.

First, each of these spells involves a normal melee weapon attack, not a spell attack, so you use whatever ability modifier you normally use with the weapon. (A spell tells you if it includes a spell attack, and neither of these spells do.) For example, if you use a longsword with green-flame blade, you use your Strength modifier for the weapon’s attack and damage rolls. [...]

True strike is nor a weapon, nor a spell attack. It's an enhancement on the weapon. It doesn't have any attack component. The weapon used in casting the spell has attack option. If you check on the character page, the spell doesn't have any hit value. Attack spells have hit values. So it's not an attack spell, thus innate sorcery doesn't work on it.

Quote from Pefcsjani >>

True strike is nor a weapon, nor a spell attack. It's an enhancement on the weapon. It doesn't have any attack component. The weapon used in casting the spell has attack option. If you check on the character page, the spell doesn't have any hit value. Attack spells have hit values. So it's not an attack spell, thus innate sorcery doesn't work on it.

 Not getting into the debate of whether it counts or not*, but the fact that it doesn't put an attack action on the DDB character sheet does not mean anything. 

It doesn't do so because the system cannot know what weapon you're using. If it explicitly said it was a spell attack, it still wouldn't appear.

* I think it should count as a spell attack, but I'm not going to argue it again here.

"attack rolls of Sorcerer spells you cast" involves a spell attack roll - slightly re-arranging the word in the phrase doesn't change this. The weapon attack roll is not an attack roll of the spell. It is an attack roll of the weapon.

I also think Innate Sorcery interacts with spells like True Strike (or Booming Blade and Green-Flame Blade, to add a few more examples to the pot)

The same would apply Repelling Blast or Seeking Spell, for the same reason: those features only require attack rolls of spells or cantrips.

Related threads:

• Repelling Blast and True Strike (and also cleave)
• Can Seeking Spell be Used with True Strike?

"Spell Attack" is a not a keyword but a descriptive phrase. Keywords are the ones which are capitalized and are essentially a single linguistic token like you're describing. As a result, the normal language conventions apply.

It might help to consider that the three weapon cantrips are all worded the same way - they create weapon attacks.

So imagine you're purchasing a Scroll of Booming Blade. What is the attack roll when you use the spell?

Scrolls have a fixed stat based on the caster's casting stat. If you're buying a generic version, it's a generic expected Int/Wis/Cha for the scribe. If you have your party's Wizard scribe the scroll, then it's their Int/Wis/Cha. That attack roll is locked in when the spell is scribed.

But Booming Blade doesn't use Int/Wis/Cha. It uses Strength or Dexterity. Moreover, you don't know which of these stats it uses until you've cast the spell. You cannot determine the attack roll at the time the scroll is scribed. There's certainly no support for the idea that it uses the scriber's Dex or Str (or any guidance about which to pick).

This should showcase why the attack roll of these cantrips has nothing to do with the attack roll of the spell. The attack roll of these spells is purely dependent on the resolution of the spell, not its casting. Everything about the attack roll is related to the additional attack you're provided, not any spell attack roll for the spell itself.

Indeed, the rules explicitly state that all spell attack rolls use a mental stat - Int/Wis/Cha. If an attack roll related to a spell uses Str/Dex - or if it must convert that ordinarily Str/Dex into a mental stat - it cannot be the attack roll for the spell itself.

Keywords - immutable tokens with a specific meaning - are capitalized. For example, "Ranged" refers to a category of weapons. Phrases that are not capitalized in text - such as "ranged attack" or "spell attack" - are not these sorts of immutable tokens and should be read in the context of the paragraph containing them.

True Strike states that the weapon attack uses Strength/Dexterity and then changes it as a result of the outcome of the spell.

The rules also state that the attack roll for a spell is your spellcasting stat - which is always Int/Wis/Cha. Not only do True Strike, Booming Blade and Green Flame Blade not follow this rule, they do not provide an exception to it nor do they claim to follow it - they explicitly state that the attack and damage are the result of a weapon.

Note that what you're arguing doesn't just break spell scrolls. It has consequences throughout the rules where you get inconsistent results if you claim that spell abilities apply to a weapon attack.

The distinction between keywords and plain text is a fairly important part of 2024 5E, not "hair splitting".

There are no examples of a spellcasting stat in 2024 5E that is not Int, Wis, or Cha. More importantly, there is a distinction between the stat you use for spells - your spellcasting stat - and the stat you use for weapons - Strength or Dexterity. If an effect is using the stat used for weapons, it is a weapon attack rather than a spell attack. This distinction is why True Strike does not have any spell attack roll associated with it (and thus cannot be affected by purely spell-based abilities like Innate Sorcery).

True Strike does not require you make an attack roll as part of its casting. It requires you make an attack roll as part of its resolution. There is no attack roll made during the casting of weapon cantrips like Booming/Green Flame Blade or True Strike. Only once they resolve are you granted a weapon attack which requires a weapon attack roll.

The distinction between the spell's casting and resolution is absolutely a thing in the rules. It's why you have to custom edit your D&D Beyond character sheet to accommodate the weapon cantrips but you don't for spells like Firebolt.

In terms of your questions:

1. You know because it explicitly tells you, as I've outlined.
2. Innate Sorcery is limited to attack rolls with spells. True Strike merely gives you a weapon attack. It's no different from the fact that you don't use Innate Sorcery with Haste or Shillelagh.

Quote from VerilyRaze >>

The distinction between the spell's casting and resolution is absolutely a thing in the rules. It's why you have to custom edit your D&D Beyond character sheet to accommodate the weapon cantrips but you don't for spells like Firebolt.

In terms of your questions:

1. You know because it explicitly tells you, as I've outlined.
2. Innate Sorcery is limited to attack rolls with spells. True Strike merely gives you a weapon attack. It's no different from the fact that you don't use Innate Sorcery with Haste or Shillelagh.

Can you please point out exactly where in the rules the "casting" and "resolution" of a spell are defined as two separate things, and where exactly in the description of the spells True Strike and Booming Blade the boundary between these two things is defined? You say it "explicitly tells you", so where exactly is that? It seems like you're reading words that I'm not seeing. Are we looking at two different things?

Here's the text of True Strike, which explicitly tells you to make an attack as part of casting the spell:

Guided by a flash of magical insight, you make one attack with the weapon used in the spell’s casting. The attack uses your spellcasting ability for the attack and damage rolls instead of using Strength or Dexterity. If the attack deals damage, it can be Radiant damage or the weapon’s normal damage type (your choice).

Here's the text of Shillelagh, which does not:

A Club or Quarterstaff you are holding is imbued with nature’s power. For the duration, you can use your spellcasting ability instead of Strength for the attack and damage rolls of melee attacks using that weapon, and the weapon’s damage die becomes a d8. If the attack deals damage, it can be Force damage or the weapon’s normal damage type (your choice).

Quote from VerilyRaze >>

 [...] True Strike does not require you make an attack roll as part of its casting [...]

 That an attack roll is made as part of True Strike is already explained in the 2024 SAC:

However, an attack made as part of True Strike works with Sneak Attack so long as it fills the normal requirements for that feature. For example, if you have the Sneak Attack feature and cast True Strike with a Finesse weapon, you can deal Sneak Attack damage to the target of the attack if you have Advantage on the attack roll and hit.

Quote from VerilyRaze >>

[...] There is no attack roll made during the casting of weapon cantrips like Booming/Green Flame Blade or True Strike. [...]

 The 2014 SAC doesn't support that interpretation:

Introduced in the Sword Coast Adventurer’s Guide , the green-flame blade and booming blade spells pose a number of questions, because they each do something unusual: require you to make a melee attack with a weapon as part of the spell’s casting.

Quote from VerilyRaze >>

The distinction between keywords and plain text is a fairly important part of 2024 5E, not "hair splitting".

There are no examples of a spellcasting stat in 2024 5E that is not Int, Wis, or Cha. More importantly, there is a distinction between the stat you use for spells - your spellcasting stat - and the stat you use for weapons - Strength or Dexterity. If an effect is using the stat used for weapons, it is a weapon attack rather than a spell attack. This distinction is why True Strike does not have any spell attack roll associated with it (and thus cannot be affected by purely spell-based abilities like Innate Sorcery).

True Strike does not require you make an attack roll as part of its casting. It requires you make an attack roll as part of its resolution. There is no attack roll made during the casting of weapon cantrips like Booming/Green Flame Blade or True Strike. Only once they resolve are you granted a weapon attack which requires a weapon attack roll.

 so by this thinking Firebolt isn't giving you an attack roll as part of its casting, but its also giving you an attack roll as part of its resolution.
Sorry this is splitting hairs, for me its a clear cut True Strike makes an attack as part of its casting => meaning innate sorcery works on it

in my view, it is a weapon attack enhanced by a spell and innate sorcery applies since it applies to spells. however, i adjust to the DM rather than argue because i got some other nasty shit in the queue if they want to be like that ;-) (i.e. silvery barbs on ring of spell storing for starters)

I wonder what is the consensus on what counter spell would do? 
For example, i use innate sorcery to get advantage on the attack (roll 11 and 13) with my crossbow and it is a hit (AC 18) because my Spell casting modifier (SCM) is +5.  If it is counter spelled, then innate sorcery does not apply and neither does my SCM bonus so we use Dex which makes +3 to hit and is now a miss.  But lets say my Dex is +3 so a +5 to hit...oh wait...which was my first roll?...so 11+5<18...miss.  right?