How to write retroactive preparation?

[qwertyu63]

Alright, I am working on some feats/ACF's (I haven't decided yet) for the Factotum. One of my more powerful ideas is the idea of "retroactive preparation". That is, the player retconning in preparation after some events have played out. The idea here is that the character is much smarter than the player and could have planned and prepared for the situation in advance. I intend for this to be useable once per day at a cost of 4 Inspiration Points.

As an example of how I intend this to be used, imagine a party escaping from a castle dungeon without their gear and being chased through the halls by guards. Luckily, there are barred windows through the halls; too small to fit through, but stuff could be dropped through them. So, this ability is activated. The player states that earlier, before being locked up, they stowed their spare handy haversack in an upcoming window with spare gear for everyone in it. Important note: to do this, the character needs to have had a spare handy haversack and spare gear for everyone; he can't just make up new gear out of thin air.

A second, more mundane, example would be declaring that, in the exact spot that a bad guy just stepped, that you placed a bear trap because you knew he would step there. As before, to do this, you would need to have had access to a bear trap to put there.

Anyway, I am aware that is a very strong ability. That isn't important now; I'll worry about balance later. What I need help with is writing this in rules text. I can't think of how to even start writing it. Maybe it can't be done, but I figured I'd ask.

[JeminiZero]

Could this work as divination like ability instead?

For example, instead of the Factotum declaring in the middle of a fight, that a trap suddenly appears where the opponent has stepped, why not have the ability occur before the fight? For example, before the fight, the Factotum wants to set a trap, and then uses this ability to infer where the villain will step, and then he sets the trap there?

[qwertyu63]

Could this work as divination like ability instead?

For example, instead of the Factotum declaring in the middle of a fight, that a trap suddenly appears where the opponent has stepped, why not have the ability occur before the fight? For example, before the fight, the Factotum wants to set a trap, and then uses this ability to infer where the villain will step, and then he sets the trap there?

Fluff-wise, that is exactly how it works (the Factotum predicts what's going to happen and prepares for it). However, doing it that way crunch-wise sounds like it would be harder on the DM (as they would have to predict what's going to happen; not an easy task).

[Grod_The_Giant]

I'd say it should be a two-part process. First, you set aside the resources as part of some nebulous "preparation." Later, you can spend the IP to have your "preparations" go off.

I had a vaguely similar ability for my Seer, if it helps:

Spoiler

Show

Always Prepared (Ex): Knowing what the future will hold makes planning a whole lot easier. Beginning at 5th level, a Seer almost always has the right tool for the job somewhere on their person.

At any point, a Seer may spend any amount of gold, adding it to a sort of trust fund. As a move action, he may expend one Foresight Point to spend up to 500 gold per Seer level to purchase a single item, such as a scroll or vial of acid, at its full market price. Items produced in this fashion may be deposited back into the fund— they are lost, but two-thirds of their market price is added to the fund.

This ability only functions if the Seer has access to his own storage space— pockets, backpacks, saddlebags, and so on. The DM may veto rare or otherwise unavailable items, in which case this ability is not considered used— neither action nor Foresight point nor gold is expended.

[qwertyu63]

I'd say it should be a two-part process. First, you set aside the resources as part of some nebulous "preparation." Later, you can spend the IP to have your "preparations" go off.

I had a vaguely similar ability for my Seer, if it helps:

Spoiler

Show

Always Prepared (Ex): Knowing what the future will hold makes planning a whole lot easier. Beginning at 5th level, a Seer almost always has the right tool for the job somewhere on their person.

At any point, a Seer may spend any amount of gold, adding it to a sort of trust fund. As a move action, he may expend one Foresight Point to spend up to 500 gold per Seer level to purchase a single item, such as a scroll or vial of acid, at its full market price. Items produced in this fashion may be deposited back into the fund— they are lost, but two-thirds of their market price is added to the fund.

This ability only functions if the Seer has access to his own storage space— pockets, backpacks, saddlebags, and so on. The DM may veto rare or otherwise unavailable items, in which case this ability is not considered used— neither action nor Foresight point nor gold is expended.

There's an idea. I'm going to go write this now.

EDIT: Alright, I now have two feats. The first I wrote ages ago, but it fits here. The other is what I just wrote.

Cunning Preparation:
You always seem to have just the right thing.
Prerequisites: Inspiration class feature
Benefit: You may carry up to 100 gp of unspecified items. As a standard action, you can spend 1 inspiration point to dig through your things to retrieve an mundane or alchemical item you pick at that time, deducting its value from the amount of unspecified items you have. You can replenish your unspecified items by spending a hour and gold equal to the amount you wish to replace.

Cunning Foresight: (this is the new one)
Your foresight and cunning allows you to lay out long reaching plans.
Prerequisites: Inspiration class feature, Cunning Preparation, character level 9th
Benefit: You may, at any time between encounters, set aside time. While you are setting aside time, you are not present. You may set aside up to 1 hour of time and can only set aside 1 block of time at once (if you set another, the first is lost). Once per day you can spend 4 inspiration points as a standard action to declare what you did during the time you have set aside. Once used, a block of set aside time is lost.

[Gildedragon]

It sounds a lot like the pathfinder Pathfinder Chronicler's Deep Pockets ability (fluff and all) which is one I suggest for filling in the 6th level gap:
The crunch:

carry unspecified equipment worth up to 100 gp per class level. This can be any kind of gear that can reasonably fit into a backpack, including potions and scrolls (but not any other sort of magic item), no item weighing more than 10lb.

As a full-round action: retrieve an item specified at that time, deducting its value from the allocated amount of cost. This item cannot weigh more than 10 pounds.

To refill: spend a couple hours and the missing gold to replenish

The feat seems pretty good, though it ought be a free action per use. You get "factotum level" in prep rounds, so at level 20 you could trigger an action that took 2 mins to prep, or an action that would have taken a single round twenty times.