Recreating Prepublished Thief Skills (B/X)

The story I have been told is that the fellow who originally came up with the thief class, Gary Switzer, originally pitched a skill system very different from what made it to official print. Rather than the much-maligned percentile chance to climb sheer surfaces, pick pockets, and so on, a thief simply attained their skills with the progression that a magic-user attained their spells, with varying levels. The main difference of course was that a skill was not expended for the day upon use.

This always seemed interesting to me, so I've decided to try to recreate that here, using a few thoughts of my own for diffent thief skills but largely stealing them from ktrey's list of alternate thief skills I commented on once before. Unfortunately I don't have the OG list Switzer came up with, but I think the result is still strong.

A skill system cannot replace cautious play or save reckless play.

A thief learns follows the magic-user's spell slot progression, learning a 1st-level skill at first level and a new skill each level, gradually selecting from more powerful skill lists. They can practice new skills in the same way a magic-user researches spells, learn from manuals and mentors in the way a magic-user does, and so on. With a week of practice, a thief can switch out skills known into their skill slots, which represent the abilities they're keeping up on and can employ while adventuring.

In general, the effect of a skill should be clear from its name. I will provide parenthetical clarification and advice. This article assumes that a PC is generally competent and can do anything with the right tools and time, so thief skills should go above and beyond that standard.

1st

1. Climb Sheer Surfaces
2. Trap Circumvention
3. Hear Noise (6-in-6 chance)
4. Hide in Shadows (will not be seen if holding still in shadow. Remember, an area with a single light has many shadows)
5. Open Locks (only requires a dagger or similar tool. Takes 1 Turn for good locks, 1 round for shoddy ones. Ineffective against magic locks)
6. Breath Control (among other things, hold your breath for 3 minutes while exerting yourself or 10 while keeping still. Can decline to inhale even when surprised.)
7. Identify/Diagnose Poison (know mechanical effects and any medical recourse. Must see effects or get a waft or something.)
8. Law (among other uses, may ask DM "is there any legal trick I can use to do X?" Learn alien law codes in an hour with a law book. Attain a frightful reputation in any settlement in a week.)
9. Juggling (among other uses, skilled enough to hold three hands'-worth of objects at once)
10. Balance
11. Appraisal (anow value in normal circumstances, always spot a forgery)
12. Contortion (among other things, slip most bonds automatically)

2nd

1. Move Silently (+1-in-6 chance of surprise when you might be spotted, automatic surprise when you can't be.)
2. Find/Remove Traps (6-in-6 chance of discovering when searching an area. Requires the minimum conceivable time and tools)
3. Pick Pockets (can discern what's in a container by brushing past it. Automatically succeeds with plausible objects, but foe can save vs devices to notice 1d4 Turns later.)
4. Mob Agitation (turn a grievance into immediate action. Normal peasants test MOR before participating in deadly violence.)
5. Impersonation
6. Ventriloquism (range 30 feet in normal circumstances, 60 in echoey spaces) 
7. Forgery (only requires a writing implement, paper, and, if copying a specific person, a handwriting sample)
8. Smattering of Language (speak all unrestricted languages with the fluency of a two-semester course. No alignment languages, secret tongues, or dead script)
9. Arson (fires spread 1 room each Turn, or 2 with accelerants. Requires flammable floors or beams, but can greatly damage constructions that are mostly stone.)
10. Snares and Alarms (by default, you're assumed to have string and a few bells. By default, snares catch all unintelligent creatures who pass by and can't free themselves easily, but with better preparation can have stronger effect.)
11. Innuendo (communicate message to specific people without saying it outright)
12. Decryption (at slow reading speed)

3rd

1. Drug Tolerance (still get benefits, if any)
2. Explosives (can manufacture in any village. 50 gold makes a petard, 500 makes enough powder to level a small building or tear the floor out of a ballroom. Other forms are possible. Takes 1 hour of work per 25 gp in cost.)
3. Antidotes and Antivenom (always specific to particular types of poison and venom. Each dose costs 100 gp to manufacture, but in some places the cost may be halved due to the knowledge of herbalists or availability of ingredients. Must be applied within 3 Turns of the affliction, or 1 Turn if deadly.)
4. Double Life (maintain a secret identity. Among other things, can replace most required sleep with disguised socializing and relaxation.)
5. Sapping (with a team, can dig 50 feet in one day. At will, can choose when an undermined wall will collapse.)
6. Camouflage (by default, you're assumed to have the needed supplies. +1-in-6 surprise when traveling through a specifically appropriate area, or automatic surprise when lying in wait.)
7. Propaganda (published or preached criticism always finds purchase, either with the have-nots against the haves or vice-versa)
8. Open Magical Lock (Requires Open Lock skill. only requires a dagger or wand. Takes 1 Turn for good locks, 1 round for shoddy ones. Always works as long as there's a mechanism, even one as simple as a hinge.)
9. Poison Manufacture (can manufacture in any village, forest, or badland. 50 gold makes a contact numbing agent, 500 makes an odorless bane that causes a save vs death when ingested. Other forms are possible. Takes 1 hour of work per 50 gp in cost.)
10. Hide Infravision Signature (Requires Hide In Shadows skill. Will not be seen if holding still in shadow, even thwarting infravision/darkvision)
11. Identify/Diagnose Curse
12. Appraise Magic Item

4th

1. Venom Immunity
2. Poison Immunity
3. Sopoforic Manufacture (can manufacture in any village, forest, or desert. 25 gold makes an inhaled knockout fluid, 250 makes an grey paste that causes a save vs death or fall asleep when introduced to the bloodstream. Other forms are possible. Takes 1 hour of work per 50 gp in cost.)
4. Sense Benevolence
5. Gambling (determine outcome in all games of chance. Once per settlement, may spend a week to win a lot of coin.)
6. Find/Remove Magic Traps (Requires the Find/Remove Traps skill. Detects even when there is no non-magical sign. Deconstructs even when there is no non-magical mechanism.)
7. Smattering of Restricted Language (speak and write all restricted languages with the fluency of a two-semester course-- alignment languages, secret tongues, and dead script)
8. False Death (fake death utterly, even stilling heartbeat. Cannot be made to cry out, cannot be tickled, don't need to blink, etc.)
9. Sincerity (Defeat magical scrying and truth-compelling magic utterly with doublethink that says you really are telling the truth, or that you're not really there, etc.)
10. Echolocation (range 100 feet in normal spaces, limitless in echoey spaces.)
11. Deathtraps (may construct them with minimum conceivable tools and time.)
12. Wall-Running (up to 30 feet)

5th

1. Scroll Use
2. Alchemical Duplication (create potions as a magic-user can)
3. Lie Detection
4. Sense Ambush (and therefore, can't be surprised by them)
5. Bushwhacking (when camping and lying in wait, always get surprise)
6. Diving Dodge (go prone to avoid a ranged attack or beam spell, etc.)
7. Deprogram (Published or preached criticism always finds purchase among the charmed, compelled, indoctrinated, and others who are normally rendered unable to be persuaded.)
8. Radiation/Mutation Immunity
9. Belong (your presence alone is not suspicious except to the inner circle of secure locations)
10. Hypnosis (with a Turn of work, can make someone sleep, make them suggestible, change their habits, implant a trigger, etc. Extended or drastic triggers can be thwarted with a save vs devices. Cannot hypnotize someone into harming themselves directly.)
11. Incite Strike (Requires the Propaganda skill.)
12. Jailbreaking (from the inside. Creates an escape opportunity in 1d6 days unless in solitary confinement or similar.)

6th

1. Cursebreaking (always specific to particular types of curse. Each ritual costs 100 gp to develop, but in some places the cost may be halved due to the knowledge of seers or availability of relics.)
2. Exorcism (takes 1 Turn per HD of the target spirit. Interruption does not foil any progress as long as you can keep chanting.)
3. Magical Law (among other uses, may ask DM "is there any linguistic trick I can use to thwart this magic compulsion?" Understand the effect of combining two forms of magic before it is done. Attain a frightful reputation among fey in a week.)
4. Sense Doom (get a funny feeling before something bad happens to you, not caused by you or your allies)
5. Blast Immunity (requires freedom of movement. Applies to fireballs and most things that require a save vs breath.)
6. Greater Pick Pockets (Requires the Pick Pockets skill. Automatically succeed with any object not in the target's hand or that would require a disassembly process, but foe can save vs devices to notice 1d4 Turns later.)
7. Incite Coup (Requires the Incite Strike skill.)
8. Catch Spell (beads, beams, bolts, etc. Can set down carefully or try to throw back on your turn.)