Warcaster/Sentinel feat combo

[Whit]

Hello. I was so wondering if this is a good combo. I will be a melee Forge cleric
Warforge for casting spells with shield. Con save advantage fir concentration spells Also can cast a 1 target spell instead of opportunity attack
Sentinel opportunity attack with melee drop movement to 0. Reaction melee attack on target who attacks adjacent allies. Thus dropping movement to 0.

I’ll have higher ac than anyone. Forge gives +1 to non magic armor. Forge gives +1 when wearing armor. Include shield and eventually magic items and your looking at plate 18 shield 20 forge Magic armor +1 21, forge bonus wearing armor +1 22 add magic items and it goes higher.

[Reynaerde]

Reaction melee attack on target who attacks adjacent allies. Thus dropping movement to 0. I'm afraid the reaction attack is not an opportunity attack, so the speed reduction is not triggered by it.

[Anymage]

Remember that OAs do eat your reaction. Action economy issues keep this from getting too strong. Especially with Sentinel, only being able to use it once per round does limit you. (Also, the punishment attack for Sentinel is not an OA and thus does not remove the enemy's movement, but in practice an enemy who attacks an ally is likely to stay in the same rough area anyways.)

The bigger question is when you want to take these feats. VHuman and grabbing the other feat at fourth level can work, but if not going vhuman squeezing in two early feats means that your prime stat will be behind. They're good feats, but raw ASIs are also good and sometimes you care more about that than a breadth of feats.

[Whit]

As a forge cleric I will have spirit guarding hitting as well. So if I’m next to the fighter and they stay in melee there will be continued damage From spirit guardian. And if they attack my ally Within 5 ft Of me, I can reaction melee attack.

If they try to disengage and give opportunity attack I can hit and drop them to 0 movement
Or with warcaster I can decide to cast a spell such as command, or inflict wounds instead of using sentinel.

[CheddarChampion]

To clarify for OP, the reaction attack against an enemy that attacked an ally isn't an "Opportunity Attack" and thus doesn't drop speed to zero.
Warcaster spells not counting has already been mentioned. But certain spells, such as Hold Person, can drop the target's speed to zero anyhow.

Not that it was asked, but you also can't replace the 'retributive attack' part of Sentinel with a warcaster spell.

All in all there is synergy but no interaction.

[Whit]

Ok so that confuses me on sentinel first part that says
When you hit a creature with an opportunity attack, the creatures speed becomes 0 fir the rest of the turn.