What happens when you use the Knock spell on Dimensional Shackles?

Question

The knock spell's description reads:

Choose an object that you can see within range. The object can be a door, a box, a chest, a set of manacles, a padlock, or another object that contains a mundane or magical means that prevents access.

A target that is held shut by a mundane lock or that is stuck or barred becomes unlocked, unstuck, or unbarred. If the object has multiple locks, only one of them is unlocked.

If you choose a target that is held shut with arcane lock, that spell is suppressed for 10 minutes, during which time the target can be opened and shut normally.

When you cast the spell, a loud knock, audible from as far away as 300 feet, emanates from the target object.

As far as I see it, the description of the knock spell describes 4 things:

• What the knock spell can target.
• What happens if the knock spell targets something locked by a mundane lock, or is stuck or barred.
• What happens if the locking mechanism is specifically the spell arcane lock.
• The spell creates noise.

Valid spell targets include magical locks, but they aren't a mundane lock, and we have good grounds to presume they aren't limited to the arcane lock spell either.

Is something locked by a magical lock considered "stuck" for the purpose of what happens to a stuck object? This would be strange to me, because why then do they specify mundane lock?

Moreover, the part referring to things that are locked by a mundane lock, stuck, or barred seems to have an inclination towards the mundane (non-magical).
Are there magical means of making something stuck which would be included in this description? If so, where is the line between being magically locked and magically stuck?

Is the creation of noise the only result for using the knock spell on a magical lock that isn't arcane lock?

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I'm interested in the answer to this because I'm wanting to break out the Replicate Magic Item infusion on my artificer to replicate dimensional shackles. Dimensional shackles seem to be magically locked for all intents and purposes. Moreover, the item is designed to prevent teleportation; among any humanoid, they were probably made for mages. Can a mage simply open them with knock (presuming they know the spell and have it prepared)?

Answer 1

There's a lot in the post, but it seems to be that your actual question is this:

Can a mage simply open them with knock (presuming they know the spell and have it prepared)?

The answer is "yes".

Dimensional Shackles:

You can use an action to place these shackles on an Incapacitated creature. The shackles adjust to fit a creature of Small to Large size. In addition to serving as mundane Manacles, the shackles prevent a creature bound by them from using any method of extradimensional Movement, including teleportation or Travel to a different plane of existence.

(emphasis mine)

The shackles have two effects:

• They serve as mundane shackles
• They suppress teleportation and other extradimensional movement.

The Knock spell has only a verbal component, so having one's hands bound does not prevent the casting of the spell. The physical restraint aspect of the shackles is limited to the description, i.e. mundane shackles, something that the Knock spell clearly spells out as something it can open.

Of course, once free of the shackles, the mage can then perform whatever other extradimensional movement they want, since the suppression of that type of movement applies only to "a creature bound by them".

If you want to keep a caster, who might have Knock available to them, bound by the Dimensional Shackles, keep them quiet. A simple gag should be sufficient.