If I have a pair of adamantine daggers could I use them to help with my skill check to climb a stone wall? Or do I have to reduce the hp of the wall to 0 to do that?
[RPG] use a pair of adamantine daggers to help climb a wall
As a matter of fact, Spider Climb does not allow to traverse frictionless surface automatically, much as the spiders can't traverse glass, for example. All it does is granting climb speed to its subject, and that doesn't even mean automatic climb success:
A creature with a climb speed has a +8 racial bonus on all Climb checks. The creature must make a Climb check to climb any wall or slope with a DC higher than 0, but it always can choose to take 10, even if rushed or threatened while climbing. If a creature with a climb speed chooses an accelerated climb (see above), it moves at double its climb speed (or at its land speed, whichever is slower) and makes a single Climb check at a -5 penalty. Such a creature retains its Dexterity bonus to Armor Class (if any) while climbing, and opponents get no special bonus to their attacks against it. It cannot, however, use the run action while climbing.
Still, climb skill could be used to traverse horizontal surface
With a successful Climb check, you can advance up, down, or across a slope, a wall, or some other steep incline (or even a ceiling with handholds) at one-quarter your normal speed. A slope is considered to be any incline at an angle measuring less than 60 degrees; a wall is any incline at an angle measuring 60 degrees or more.
but in the case of "magically frictionless" surface skill check will either receive penalties (-5 for slippery surfaces, I'd suggest at least -10 in the magical case) or be outright impossible (if it is also perfectly smooth).
Note: creatures with climb speed moves at its full climb speed while climbing, or at double that (but not greater than its base land speed) while performing accelerated climb.
Anaruoch: The Empire of Shade includes a 50-ft.-tall, 10-ft.-wide waterfall inside a cavern. Features of the Area describes the waterfall as follows:
Climbing beneath the waterfall requires a successful DC 35 Climb check. Flying through it requires a successful DC 20 Strength check to avoid plummeting to the pool below. (73)
Extrapolating from this, a creature that wants not to be swept away when confronted with a suddenly flooding passageway should probably allowed to make a Strength check (DC 20) if the creature has means of going against the deluge in the first place (e.g. appropriate handholds, a fly speed, an active effect like the spell spider climb, extreme weight due to the spell iron body). That is, effectively the creature has chosen to try to stay in place while the waterfall flows over the creature. Success means the creature can take its actions normally; I suggest failure means the creature's swept away (rather than having the creature plummet).
After a successful Strength check made to avoid being swept away, forward progress against this ersatz waterfall should require a climbing creature to make Climb skill checks (DC 35). (Note: While neither hydrologist nor spider-eating spelunker, I think that DC's about right considering the potential water speeds were discussing. I don't know if matters if failure means you technically fall or, instead, are technically swept away as both involve facing tons of water coming right at you! I'm guessing, but at this point traversing the horizontal seems like it should be as difficult as traversing the vertical. Comments can take up this issue, and, of course, the DM can adjust the DC as he sees fit.)
How other creatures make forward progress is up to the DM, but flying creatures likely must swim (perhaps in stormy waters), and super heavy creatures likely use their land speed (albeit maybe vastly reduced—this is, after all, pretty difficult terrain). All such creatures probably also need to hold their breath.
After a failed Strength check, the creature's swept away. Aquatic Terrain under Flowing Water describes being swept away as follows:
Characters swept away by a river moving 60 feet per round or faster must make DC 20 Swim checks every round to avoid going under. If a character gets a check result of 5 or more over the minimum necessary, he arrests his motion by catching a rock, tree limb, or bottom snag—he is no longer being carried along by the flow of the water. Escaping the rapids by reaching the bank requires three DC 20 Swim checks in a row. Characters arrested by a rock, limb, or snag can’t escape under their own power unless they strike out into the water and attempt to swim their way clear. Other characters can rescue them as if they were trapped in quicksand (described in Marsh Terrain, above).
Emphasis mine, and which should cover equally well a rapidly flooding cavern.
There's no specific rule to cover this, but your GM could reasonably let you use them somehow.
It's plausible that you could use the daggers as improvised tools to assist your climbing, but there is no specific rule which addresses doing this; judgement on the part of the GM is required.
For many skills, climb included, you can get a +2 circumstance bonus if you have an appropriate tool or kit to use in the attempt. Having a climber's kit grants this bonus to climbing checks. Your GM might rule that a pair of adamantine daggers you can drive into the wall relatively easily to use as handholds is equivalent to having a climber's kit, and so give you a +2 bonus.
Alternatively, the Climb skill does have a section on making your own handholds and footholds, which states:
Normally this requires pitons which you embed and leave in the wall (so doesn't work with just two daggers), but it does allow for a character climbing up an ice wall, specifically, to cut their own handholds using an appropriate tool. With an adamantine weapon, it is easy to imagine that you could do the same thing to rock and other walls, so you could chisel out handholds and footholds as you go. It would take a very long time, since you'd be taking a minute or so for every three feet of climbing distance in order to chisel out a decent gap to use, but the DC would be reduced to only 15, and the handholds/footholds could then also be used by following party members to make getting up the wall easier.