Clone Project: The Thief

I'm beginning to look at the Thief class for Liber Zero, which probably surprises many of you. After all, the goal of Liber Zero is to stick to the LBBs, right?

Pretty much, but I do have a vague plan for the document that comes after the shorter reference document. I want to focus on the LBBs as a stand-alone system, keeping the core as small as possible; I'm hoping 8 to 12 pages for the reference document and 30 to 50 pages for the longer version with plenty of examples. After the core section, I want two additional sections: Variants and Appendices.

The Variant section would mostly alternate mechanics that add detail to the core with change the expression, arranged in topics, with 1 to 3 pages per topic in the full document. Prospective topics include Experience, Hit Dice, Damage, and Weapons. These changes pretty much must be decided before play begins.

The Appendices section would be optional rules for particular campaign flavors; unlike the Variants, these would change the interpretation of the core rules or the expression of the implied setting. Prospective appendices include Urban Fantasy, Courtly Fantasy, Eldritch Fantasy, Science Fantasy, Arcane Fantasy, and Mythic Fantasy. Again, each appendix would be short (around 5-8 pages,) primarily covering necessary changes for each flavor; they more or less cover some of the material in the original supplements, in order of appearance.

The Thief will probably be in the Urban Fantasy Appendix, along with the Assassin subclass. So, I've been thinking a little about how to handle the class. I'm nowhere near done, but the basic progression is pretty easy: hit dice are the same as Magic-Users, but they gain experience faster than any other class (+40% bonus to earned experience.) The skills will all be translated from percentile-based to other die types: most will be based on modifiers to the d6 Situation roll mechanic, but filching items will be treated as an attack; all the skills will be available to non-thieves, but at the "zero level" (no level-based bonuses.)

... Except at least one skill, opening locks. I just noticed something about the Supplement I description of this skill: "open locks by picking or foiling magical closures" (emphasis mine.) I don't remember that being in any other edition. Does anybody else? It seems like an appropriate skill to make the Thief on a par with the other classes, and certainly in keeping with the interpretation of Thief skills as extraordinary abilities. I'll probably make this an "attack" roll as well: d20 + Thief Hit Dice => 20 opens any lock. That's for magical locks. Non-magical locks are treated as AC 9, maybe AC 5 for complex ones, adding the AC to the die roll.