I am currently running Tomb of Annihilation and letting one of my players play a Revised Artificer homebrew.

One of the features under the Gadgetsmith subclass is a Grappling Hook, with this mechanic:

As an attack or as an action, you may target a surface, object or creature within 20 feet. If the target is Small or Smaller, you can make a Grapple check to pull it to you and Grapple it. Alternatively, if the target is Medium or larger, you can choose to be pulled to it, however, this does not grapple it.

Initially, this is no big deal as the character has weak HP scaling (D8), so it was fine for the player to grapple himself around the battlemap to safety. He then, however, got this upgrade:

Enhanced Grappling Hook:

You enhance your grappling hook, increasing its range to 40 feet. Additionally, the enhanced power of the grappling hook means that when pulling yourself to a larger or larger creature or object, you can drag one medium or smaller willing or grappled creature within 5 feet of you with you.

Emphasis mine. That one clause is beginning to cause a headache for me, as it is a resource free, instant Misty Step + 1 ally to any object within 40ft.

The hook, because he is an Artificer, is magical. It does not operate like a normal grappling hook in that it needs some sort of nook, crack, or lip to hook onto. Instead, imagine a magical magnet that sticks to any object, and pulls you perfectly like the 3-d movement gear from Attack on Titan. The hook is currently incapable of failing, although I am open to nerf suggestions.

I am certain this will break many obstacles in the actual Tomb. To give a few examples:

• 4B – Second Puzzle Door: The player can grapple himself and a companion to the ceiling when the level appears. The pit trap is negated when the lever is pulled.

• 5/5A – Trapped Corridor: Once the player spots or triggers the plates, he can transport the entire party to and from the end of the hallway. Negates the pressure plates trap.

• 15 – Wind Tunnel: The player simply needs to grapple across the tunnel, never activating the fan itself. He can transport the entire party this way. Negates the entire trap.

• 20 – False Tomb: The player can grapple another player out of the room should they trigger the trap. Should he be unable to escape, he can also grapple to the ceiling to increase his survivability against the Wine Weirds. (I actually don't have a problem with the second part of this).

• 37 – Winds of Pandemonium: The player can grapple through the entire length of the room, transporting the entire party across the platforms requiring jumps. Trap is negated.

• 44B – Inside the Vault: The player +1 ally can negate the slippery floor by grappling to the walls or ceiling. This doesn't do much about the Invisible Beholder, however.

• 48 – Shagambi's Tomb: The player can grapple directly to Shagambi's Tomb, eliminating the tip-toeing section of the walk. It negates a lot of the threat in this tomb, although it will trigger 1 sound if he does it optimally.

• Level 5 – Gears of Hate: The player can negate the entire gear experience by grappling to the ceiling, transporting players this way.

I think you get what I'm saying at this point. The hook+1 mechanic is broken when it comes to dealing with a significant portion of the Tomb's obstacles.

There is the option to nerf it entirely and render it unusable in the Tomb; the dungeon does have powerful, world-altering enchantments upon it, so it would not be too out of the box. I am hesitant to do this, however, since the player greatly enjoys grappling around and being mobile.

Overall, my key grievances with this mechanic are this:

• The Grappling Hook is free. It requires no resource usage to transport himself and a companion within 40ft. Compare this to Fly, which also negates a lot of aspects of the Tomb, but is a resource that is used as the player just ferries everyone across/over obstacles.
• There is no check involved. He can bring any willing companion without fail. However, if I were to involve an Athletics check, his character would almost always fail abysmally.
• It works without fail. This aspect, I am fine with and have no desire to nerf.
• It is core to his kit. If I were to take it away, it would crush the player, and I have already allowed it far too long to remove it entirely.

Is there a creative solution/compromise I can bring to this player so that I can make the Tomb experience more gripping and exciting? Or am I blowing out of proportion how good his grappling hook ability is in respect to this adventure?

Answers that cite prior experience with either this module or this/a similar mechanic would be greatly appreciated.

This is the party currently – Gadgetsmith Artificer, Berserker Barbarian, Moon Druid, Shadow Monk, and Clecic 1 Fighter X multiclass.