Pact of the Tome, Sorcerous Burst, & Agonizing Blast

Pact of the Tome grants the warlock some cantrips from any class, and then those cantrips count as warlock spells. Then the warlock can take Agonizing Blast and choose one of those cantrips. So my question is this:

If a warlock obtains Sorcerous Burst and gets bonus rolls from getting an 8 on a d8 roll, do those bonus rolls get the warlock's charisma modifier added to them?

Those extra d8s on Sorcerous Burst are still part of the same damage roll, so you're not adding the Charisma modifier to each one; you're adding it once to the total.

For spells like Eldritch Blast that can have multiple, separate damage rolls, you would add it once to each of the damage rolls separately.

Quote from wagnarokkr >>

Those extra d8s on Sorcerous Burst are still part of the same damage roll, so you're not adding the Charisma modifier to each one; you're adding it once to the total.

For spells like Eldritch Blast that can have multiple, separate damage rolls, you would add it once to each of the damage rolls separately.

 I figured what you said for Eldritch Blast. For Sorcerous Burst, I thought maybe since it specifies rolling each extra d8 separately that they might count since Agonizing Blast says "You can add your Charisma modifier to that spell’s damage rolls," and those extra dice are all explicitly extra rolls that then get added to the total damage.

On an unrelated note, how do I link abilities and such so that they have pop-up windows like in your post?

I agree with wagnarokkr.

The question reminds me of a similar debate about whether the "extra" damage from True Strike is affected by Agonizing Blast a second time (effectively applying it twice). It isn't, because "extra" in this context means "additional", not "separate."

This was the thread, if it's interesting to you, Nebuul: True Strike + Agonizing clarification - Rules & Game Mechanics (also related: Agonizing Blast Damage Roll(s) - Tips & Tactics)

And from those threads, I'd like to highlight this conversation with the Dev:

@quadhund If I make 1 attack with a longsword as a part of casting Green Flame Blade, while having the Hex spell affecting the target, and then I use Divine Smite once the attack hits, how many damage rolls are there?
@JeremyECrawford When something in the game (Sneak Attack, Divine Smite, hex, etc.) causes your attack/spell/etc. to deal extra dice of damage, those dice are added to the damage the effect is already dealing, if any. It's one big damage roll, extra damage included. 
@DaveWil33 Would only be a second damage roll if there was something locked behind a save like poison damage, yes?
@JeremyECrawford If an attack has a damage roll but also a second damage roll (not extra damage) that is contingent on a saving throw, the damage of that second source is a different damage roll from the first.
@RubiksMoose how do you distinguish between second damage roll and extra damage?
@JeremyECrawford Separate damage rolls are delivered by separate attack rolls, saving throws, or other processes. Extra/bonus/additional damage is called extra/bonus/additional damage.

Quote from Nebuul >>

[...] On an unrelated note, how do I link abilities and such so that they have pop-up windows like in your post?

 I forgot this :( Check How To Add Tooltips As an example: [ spells ]Polymorph[ /spells ] (just remove the spaces)