What exactly do the surges of cohesion and tension do

[Aluminum]

I'm making a Dungeons and Dragons class based on the Knights Radiant and I've hit a snag with regards to these two surges. All help is welcome. Thanks

[Pagerunner]

I've pulled some quotes together in this topic, which you may find helpful:

 

[Inky]

We're not sure. They seem to involve softening or hardening materials but we're not sure what they do exactly. 

[Karger]

We don't know.  Brandon has been coy on the subject.

[RShara]

1 hour ago, Pagerunner said:

I've pulled some quotes together in this topic, which you may find helpful:

 

This is probably the best explanation we have so far.

[Wandering Investor]

Cohesion temporarily weakens the bonds between molecules and can then manipulate their arragnement, before their bond strength returns to normal. And example would be turning a stone wall into a stairway, the stone softens, changes shape, and then re hardens.

Tension on the other hand seems to temporarily strengthen the bonds between molecules, allowing them to take more strain before breaking, and an additional power to restore, and maybe even create, bonds, holding things together even after the stormlight fades. Examples of these include Dalinar strengthening his skin in his vision, and also Dalinar sticking statues back together.

The exact mechanics aren't fully know, but the post Pagerunner linked seems like a pretty plausable explanation.

[Iridium Savant]

This is some of what I have put together for my cosmere DnD campaign.  They are based off Pathfinder rules so may be a bit different than what you are making but hope it helps you come up with some ideas.

Spoiler

Surge of Cohesion 

Soften Object: 1pt - (Std Action); Decrease the hardness of a touched object by 5 points for 1 minute.  If the hardness is reduced to zero or below with this ability the caster may attempt a free sunder attempt against the object. 
(+1pt per additional 1 hardness reduced/ +2pt for an additional +1 on any sunder check) 

Shape Object: 3pt - (Full Round Action); The caster may mold any object with their hands like it was soft clay.  The caster may affect up to one cubic foot of material and may either apply the broken condition to the item or may repair the broken condition [depending on complexity of the item and nature of the break the DM may require an appropriate craft check from the caster as part of the Full Round Action]. 
The caster may also use this ability as part of a Sculpting, Blacksmithing or other appropriate type of Craft Skill to complete a full day's work in only 2 hours instead of the normal 8[The caster only needs to spend the 3pts of stomrlight once to apply this special use to their craft skill]. 
(+2 for 1 additional cubic foot of material affected) 

Advanced Soften Object: 7pt - (Full Round Action); This spell turns the ground in a 20ft cone into a pool of mud like liquid for 3 rounds. The depth of the mud pool is 5ft, a creature unable to levitate, fly, or otherwise free itself from the mud sinks until hip- or chest-deep, reducing its speed to 5 feet and causing a -2 penalty on attack rolls and AC. Brush or similar material thrown atop the mud can support creatures able to climb on top of it. Creatures large enough to walk on the bottom can wade through the area at a speed of 5 feet. 

If cast upon the ceiling that the user is touching the mud falls to the floor and spreads out in a pool at a depth of 5 feet. The falling mud and the ensuing cave-in deal 6d6 points of bludgeoning damage to anyone caught directly beneath the targeted area, or half damage to those who succeed on a Reflex save. 

Anyone caught in the area of effect when the duration ends become trapped in that square and take a –4 penalty to their Dexterity and a –2 penalty on attack rolls. Creatures may make a Break or Escape Artist check each round to try and free themselves. 
(+3pt for an additional 5ft to the cones range/+4pt to extend duration by an additional round) 

Alter State: 9pt - (Std Action); With a touch the caster may alter the molecular state of one object by one step. [e.g. from a solid to a liquid, or from a liquid to a gas] If the item is being worn or used by another creature then the target may make a Will save to negate.  The resulting from of the item persists for 2 rounds before returning to its original sate.  Solid objects that become liquid and then solidify when a creature is in that square cause the creature to make a Reflex save or get entangled and flatfooted in the new solid puddle. 
(+3pt to affect an object one size larger/ +2pt to increase Save DC by 1) 

Surge Mastery 

Perforate Surface: 5pt - (Free Action); While moving along any vertical surface you may create easy to use hand and foot holds perfect for navigating the surface.  You and all creatures moving across the surface may do so at half their land speed without becoming flat footed. A single use of this ability is effective on all movement the caster makes for one full round.  The caster may also use this ability a second time to cause any past changes to revert back to their normal surface. 
(+3pt to last an additional full round) 

Tunnel: 9pt - (Std Action); You create a passage through any material. The passage is 10 feet deep and 10 feet wide. If the wall’s thickness is more than the depth of the passage created, then a single tunnel simply makes a niche or short tunnel. Several tunnel spells can then form a continuing passage to breach very thick walls. The caster may use this ability to instantly revert any number of chained tunnels back to their normal form. 
(+3pt for an additiona 5ft of depth) 

Surge of Tension 

Harden Object: 1pt - (Move Action); Increase the Hardness of a touched object by 5 points for 1 minute.  If the hardness of a medium or small size object increases to over 10 because of this ability then the caster may use the object as a Small or Large Wooden shield with no armor check penalty. 
(+1pt per 1 additional hardness/ +2 points for a +1 to shield AC [stacks up to 3 times]) 

Advanced Harden Object: 3pt - (Std Action); Like Harden Object but instead used to either make your clothing into medium armor with half the normal armor check penalty and no speed reduction or create a tower shield, with no armor check penalty or speed reduction, out of a large flimsy object. Either use lasts only 3 rounds. 
(+2 for +1 round/ +4 to create heavy armor instead of medium) 

Tension Step: 3pt - (Free Action); For the next two full rounds move across liquid or fragile surfaces with ease. This includes tree branches and bushes.  Treat all of these surfaces as normal terrain with no penalties. 
(+2pt to extend by 1 round) 

Tension Wave: 5pt - (Std Action); Cause a wave of distortion across the ground in a 30ft cone. Everyone within the cone must make a Reflex Save or become tripped. If the wave passes over a large pool or area of a liquid then it instead becomes a Bull Rush attempt to the edge of the cone, CMB equals CL + Intelligence. [The DM may decide to add extra effects based on the liquid] 
(+2pt to extend cone by 5ft/+2pt for a +1 bonus to DC/CMB/+5pt Reduce to a Move Action) 

Surge Mastery 

Solid Object: 5pt - (Move Action); Cause a Large size or Larger object to become solid and steady.  You can create barriers and bridges with this power and essentially alter terrain in any way the DM permits as long as you have enough objects.  The object remains like this for 10 minutes.  The caster may shorten the duration if they wish and may dismiss it with a free action as long as they are within melee range.  

Tension Jump: 5pt - (Part of a Jump Action); Gain a +15 to your Acrobatics check to Jump and you have no limit to your height. 
(+2pt for additional +1 to Acrobatics)