Has anyone tried a Sentinel Rogue?

[heavyfuel]

they are using the feat for different purposes, tanks are using it for parts 1+2 to control the battlefield (and will occasionally get a bit of extra damage from part 3); rogues are using parts 2+3 to potentially double their impressive damage output (and will occasionally do some basic battlefield control with part 1)

Sure. But still, how often do you see enemies using the Disengage action? I've seen it happen quite often, but everytime it's when they are vastly outnumbered and make a last-ditch attempt of surviving. At this point in the combat, an increase in DPR isn't particularly important.

As for the OA from attacking somebody else. That's part of my point. If the enemy is even slightly intelligent, they might as well attack the Rogue over whoever else is also in melee with them. Because of Bounded Accuracy, both characters likely pose a similar threat level and have similar defenses, so why not attack the Rogue?

Again. Not saying it's terrible, but I do think the ASI/free feat would be better spent elsewhere.

[Naanomi]

As for the OA from attacking somebody else. That's part of my point. If the enemy is even slightly intelligent, they might as well attack the Rogue over whoever else is also in melee with them. Because of Bounded Accuracy, both characters likely pose a similar threat level and have similar defenses, so why not attack the Rogue?

Most enemies don't know what feats I have, so one OA in crowded melee is a pretty reasonable expectations (especially if you have to leverage your greater maneuverability to go protect casters in the backrank while the main tanks hold up the front lines)

[Gignere]

Sure. But still, how often do you see enemies using the Disengage action? I've seen it happen quite often, but everytime it's when they are vastly outnumbered and make a last-ditch attempt of surviving. At this point in the combat, an increase in DPR isn't particularly important.

As for the OA from attacking somebody else. That's part of my point. If the enemy is even slightly intelligent, they might as well attack the Rogue over whoever else is also in melee with them. Because of Bounded Accuracy, both characters likely pose a similar threat level and have similar defenses, so why not attack the Rogue?

Again. Not saying it's terrible, but I do think the ASI/free feat would be better spent elsewhere.

I think we all agree it depends on party composition to a certain extent. Like all range party than yeah don’t get sentinel. Or if a barbarian/fighter/Paladin picked it up you can skip it too.

However, in the right party composition it can be devastating on a rogue, like any party with a Druid with conjure animals. You are basically one of 9 options to get hit and unless the DM metagames like crazy you are bound to proc sentinel a few times in every combat that counts. If the enemy tries to beeline the Druid perfect sentinel can keep it from moving.

Actually any party with good minionmancy and one other melee sentinel rogue would do real good.

[Stangler]

It really depends on the way combat is going in your party. Party composition and dm style is really important to determine effectiveness. That said I think you can compare it to the dual weapon fighting style which is worth 3 to 5 damage a round before accuracy. So a rogue at level 8 would want to be triggering the attack about once every 4 to 5 rounds. At higher levels the value goes up and it would need to be triggered less to provide value. There is also the cost of the reaction to consider which also varies by situation.

[MThurston]

"SENTINEL
You have mastered techniques to take advantage of every drop in any enemy's guard, gaining the following benefits:
• When you hit a creature with an opportunity attack, the creature's speed becomes 0 for the rest of the turn.
• Creatures provoke opportunity attacks from you even if they take the Disengage action before leaving your reach.
• When a creature within 5 feet of you makes an attack against a target other than you (and that target doesn't have this feat), you can use your reaction to make a melee weapon attack against the attacking creature."

"MIRROR IMAGE
2nd-level illusion
Casting Time: 1 action
Range: Self
Components: V, S
Duration: 1 minute
Three illusory duplicates of yourself appear in your space. Until the spell ends, the duplicates move with you and mimic your actions, shifting position so it's impossible to track which image is real. You can use your action to dismiss the illusory duplicates. Each time a creature targets you with an attack during the spell's duration, roll a d20 to determine whether the attack instead targets one of your duplicates. If you have three duplicates, you must roll a 6 or higher to change the attack's target to a duplicate. With two duplicates, you must roll an 8 or higher. With one duplicate, you must roll an 11 or higher.
A duplicate's AC equals 10 + your Dexterity modifier. If an attack hits a duplicate, the duplicate is destroyed. A duplicate can be destroyed only by an attack that hits it. It ignores all other damage and effects. The spell ends when all three duplicates are destroyed.
A creature is unaffected by this spell if it can't see, if it relies on senses other than sight, such as blindsight, or if it can perceive illusions as false, as with truesight."

The writing is clearly NOT contradictory.

Sentinel is activated when a creature makes an attack within 5' at a target other than you.

When mirror image is present the creature starts out making an attack against you and so does not trigger sentinel.

However, if they make the roll for mirror image the spell specifically states "the attack instead targets one of your duplicates".

The duplicates are NOT you. They are duplicates. You do not take damage if one is hit. Sentinel does not require that the creature make an attack against a target that is another creature. It does not say anything except it makes an attack against a target that is not you. Mirror Image specifically changes the target of the attack to one of the duplicates. This is NOT an attack against you. It is an attack against a target within 5' that is not you and is sufficient to trigger sentinel.

There is no contradiction. By RAW it works fine. Any DM can change it if they want but Mirror Image changes the target to a duplicate. The duplicates are NOT the character. Sentinel only requires an attack within 5' against a target other than you - so sentinel is triggered by an attack that selects one of the mirror images.

We can argue about lots of things but the RAW in this case is pretty clear.

It is outrageously badly written for these to work together.

I target you.
The spell targets an image.
Sentinel says they have to target you or you get to attack.

They did target you. Your spell misdirected it.

[Frogreaver]

It is outrageously badly written for these to work together.

I target you.
The spell targets an image.
Sentinel says they have to target you or you get to attack.

They did target you. Your spell misdirected it.

Actually it says "makes an attack against a target other than you".

And the attack rules say: If there's ever any question whether something you're doing counts as an attack, the rule is simple: if you're making an attack roll, you're making an attack.

Seems pretty clear the enemy made an attack against a target other than the sentinel rogue - regardless of how well intentioned.

That said, I think it's a terrible rule and would rule otherwise along with many other DM's. And since what DM's rule matters more than RAW then I submit that it's best to ask your DM if this trick works in their games.