Overview

Why Lurk?

Well, there is no definite answer to that . However from all the psionic classes that books offer (which leaves psionic rogue out of the equation) no other class offers a roguish progression and manifesting. Unfortunately lurks are below average. They have low skill points per level and no trapfinding, limiting their skill-monkey role to scouting and spying. Moreover their sneak attack progression is low to be useful in combat alone (although you can augment it with your class abilities) and the class's BAB is medium. Last but not least, the number of powers known is limited.




Pros:

Int synergy (manifesting, initiative, bonus skill points, augments).
Full manifester level.
Two good saves.
Eventually unlocks all lurk augments.

Cons:

No trapfinding for a roguish class.
4+int skill points per level for a skill-monkey.
Slow sneak attack progression
Bad fortitude save.
Medium BAB.
No bonus feats (fighter, psionic or otherwise).

Suggested Fixes

Give trapfinding
6+int skills + disable device/search as class skills.
Remove slippery mind and instead offer a rogue special ability.
Improve sneak attack progression to gain six dice eventually.
Improve lurk augments' save DC to 10 + 1/2 lurk level + int modifier. Remove the option to improve the DC of augments with power points.
Improve lurk augments to work on any attack (ranged or otherwise).
Improve BAB to full.

Attributes

Lurks are by default melee characters since lurk augments only work on melee attacks (see the feats section for more information on this). First priorities are intelligence and constitution. The first is for obvious reasons and the second one for surviving melee combat (although getting a reach weapon greatly helps). Then my first priority would be strength for melee battle and wisdom/dexterity to help your skills. Charisma is almost not needed (although will help your UPD checks).

Class Features

Weapon and armor proficiency: Simple and martial, light armor and shields. Very nice selection for a roguish class.
Powers: Int based manifesting lowers your MAD. Lurk's manifesting is like that of the bard, while the powers are roguelike. You eventually gain 20 powers known, which is limited, but you can use expanded knowledge to gain more, even outside your power list. More on power selection later.
Lurk Augment: Augment your melee attack with an ability from a little list. The good part is that you receive all of augments at the indicated level. It is an (Ex) ability, so your augments work on magic immune enemies and antimagic zones. You can use your augments as a swift action, lurk level + int modifier times per day. The bad part is that most of the powers that have a very low DC (10 + int modifier). As you level up, you will gain the ability to use two and eventually three lurk augments on the same attack.
Psionic Sneak Attack: As normal sneak attack, but you need to be psionically focused to use it. Thus you need to invest some points in concentration.
Initiative Boost: Add your int bonus to initiative checks. Eventually you'll have 16 int to manifest your powers, so it's pretty much the same with an improved initiative feat. Also an (Ex) ability, so it works most of the time.
Evasion: As the standard ability. Your reflex saves are already high, so you'll have no problem evading area effects that allow reflex saves most of the time.
Slippery Mind: As the rogue special ability.

Lurk Augments

Additional Sneak Attack: Solid ability, useful for extra damage at all levels. Assuming you spend as much power points you can on this, you gain bonus dice to your sneak attack equal to 1 + 1 per 2 levels.
Unfocusing Strike: Not very useful, even against psionic opponents.
Solid Strike: Solid It's a lot less damage than additional sneak attack, but works against all targets, even to those immune to sneak attacks.
Stunning Attack: Low DC and duration, not worth it.
Ignore concealment: Concealment spoils precision damage and thus sneak attack. You need this in order to make use of your sneak attack.
Mental Assult: This is golden :O Very useful ability against all enemies. The best part is that it doesn't have a saving throw.
Deceptive Strike: Meh, very good if you can't find a way to sneak attack your opponent. It shouldn't be a problem if you have a flanking buddy.
Sneak Attack Undead: Very useful. No reason not to use it against undead.
Ghost Touch: Most incorporeal creatures i know of are also undead, so you'll probably have to combine this with sneak attack undead, but generally it is also useful.
Power Drain: Useful if you use it in conjunction with an augment that boosts your damage, like extra sneak attack. A very nice way to replenish your pp reserve. Because the power points will stay around only until the following round, you can spend them all to maximize an augment.
Aligned Attack: I feel that this is not that useful. If you can sneak attack your target, most of the times his damage reduction will block one or two of your sneak attack dice. Moreover you receive this augment pretty late.
Sneak Attack Constructs: As with sneak attack undead.
Stygian Weapon: Wow, it's a mini-Enervation! No save, too. Unfortunately the duration is too limited, but if you can get one through, a spellcaster can benefit from the debuff to save-or-lose the target.
Planar Attack: Nice damage, but doesn't work always. Still, it's death to those outsiders and the damage is much more than extra sneak attack.
Synaptic Disconnect: The effect is very good, but the DC is extremelly low without a huge investiture of power points.
Greater Power Drain: As normal power drain.

Feats

Combat Styles

Ranged: You need three feats to make this work: Lurk augment, ranged, point blank shot and precise shot. Because lurks are feat starved, you won't be able to invest that much into starting feats. I'd advice you to go the melee way, probably investing a feat to get a reach weapon.
Melee: Lurks default to this style and requires no feats to utilize it. You can spend a feat to get an exotic reach weapon, such as a spiked chain, but you can use the martial polearms if you are having feat problems.

XPH

Expanded Knowledge: This is a wonderful feat that will get new powers from any list on your reserve. After a few levels it is a great pick.
Psicrystal Affinity: Lurks are skill monkies and this essentially doubles your skill ranks. A very nice feat to pick up on your psicrystal (when he gains the appropriate hit dice or by using psychic reformation if your DM does not believe that they actually gain hit dice) is mindsight. Psicrystals gain telepathy 30ft when their master gets to manifester level 5-6.

CPsi

Dire Stun: Unfortunately that augment has a very low base DC to make this feat even useful.
Elemental Envoy: The flying one if possible. You can do the mindsight trick with elemental envoys, which get telepathy 100ft. They require an additional feat however, so they are not so hot.
Focused Skill User: Well, most of the time you will be psionically focused to utilize your sneak attack, so this is useful. The good part is that you get to choose the skills that'll benefit from it. The bad part is that the bonus is competence.
Lurk Augment, Extra: Three extra uses. This is probably useful at low levels. You can take it and retrain later.
Lurk Augment, Ranged: I don't think that this is worth it. Read the 'combat styles' section.
Lurk Master: I'd almost always take this feat. It loses its usefulness only if you play a single classed lurk above 18 level. You are adviced to retrain it at high levels.

Skills

Autohypnosis: This skill has many uses and is quite rare. I'd max it out. All uses are great and especially the memorize part has tons of flavor and synergy for a spy.
Bluff: Not bad, you can max it out since it's the only 'social' skill you possess. Spending only 5 ranks is a great option, too, as it provides synergy bonus to many other skills.
Climb: Move along .
Concentration: You need it to get psionically focused easily (as it is crucial to your abilities) and to manifest in combat situations.
Craft: Unless you want to qualify for something, move along.
Disguise: Hey! This is actually quite nice. However you don't usually need to spend many ranks here, simple spells like disguise self (you can get it at will with a cheap hat of disguise) will provide you with fat bonuses.
Escape Artist: Not useful against you are facing a lot of grapplers.
Hide: Will help you spy and usually comes along with move silently. Put some points here if you can spare them
Jump: Just spend 5 ranks for the synergy bonus. After that it's probably not worth it.
Knowledge (Psionics): Well, this is your only knowledge so i'd do anything i could to max it out. If you can't, at least spend one rank to know something important about your field of expertise.
Listen: Again important to spies, scouts, etc. It's a good pick.
Move Silently: Check hide.
Profession: Again, only useful for qualifying for stuff.
Psicraft: Ok skill to spend some ranks, especially if no one else possess it.
Sleight of Hand: Useful for stealing and acquiring items that provide information.
Spot: Check listen.
Swim: Move along.
Tumble: Moving around the battlefield without provoking attacks of opportunity is important when you cannot tank in melee combat. Mobility is the key to winning most battles.
Use Psionic Device: Whatever your other skill selection is, i'd try to max this out. It's probably your first priority.

Manifesting

General Tips

Don't get too many swift action combat buff powers. Lurk augments use a swift action and you only have one swift per round. It's going to interfere eventually with your augments.
Don't invest much on powers that require high DCs to work. Lurks aren't going to pump their intelligence much your power selection should reflect this. Support and sneaky powers are much more useful.
Remember to pick good all around powers. Your selection is too narrow and you don't have many options. Good multi-powers are better.
Don't get powers that can be replicated easily by a cheap item. If you do, make sure you'll use them a lot, otherwise it's a waste of space.
Don't get powers that you'll use once or twice in an adventure or powers that specialize (like a group of enemies characters with a certain subtype).

Level 1

The Good:

Conceal Thoughts: Impressive. 1 hour/level duration, huge bonus to bluff checks and a saving throw bonus to those try to enter the target's mind. I believe that this is a good power for any lurk to select.
Detect Psionics: Having this always handy is important. It's a good pick.
Dimensional Pocket: I like this very much because it has tons of uses for a relatively cheap price. You can use it to pass weapon from a guard, steal something small, etc.
Grease, Psionic: Now we're talking! This is going to help you delivering your sneak attacks at low to mid levels. I'd almost pick this power. It also has many other offensive applications, like disarming your opponents!

The Average:

Empty Mind: Your will save is high, but wisdom is more or less a dump stat for you. It's useful as a panic button in case you targeted with an important save-or-lose spell.
Chameleon: Not bad, it removes the need for a magic item that grants an enhancement bonus on your hide skill and the bonus is quite good for a first level power. If you are into hiding, take it, the duration is nice at all levels.
Compression: Not sure about this. At any case you need to use a ranged weapon in order to make this work. It is useable after 3rd level, because that's when you're gonna be able to augment its duration to minutes/level.
Precognition, Defensive: Not sure about this. It seems to me that it requires a large investiture of power points to be useful.
Precognition, Offensive: As above.
Skate: This is a lot more useful than the burst power of the same level. You can use it for general purposes and on your teammates, too. However i think that there is no space for this in lurk's low powers known.
Synesthete: I really like this, it's a good pick.

The Bad:

Float: Its duration is low and the swim speed can be achieved by other means. I'd skip it.
Extend Range: Mostly useless, unless you take the feat that enables you to use your lurk augments on ranged attacks. Still, ranged augments only work within 30ft, so don't pick this.
Far Hand: It's ok if you want to pick stuff from a distance, but mage hand items are pretty common.
Know Direction and Location: Unless you are planning to plane hop a lot, this is not that useful.
Mighty Spring: Sure, nice, but not that useful to lurks.
Distract: Meh, its mind-affecting and you can't augment it. It's usefullness is going to scale down pretty quick.
Catfall: This is useful if you fall, but feather fall items are quite common.
Adrenaline boost: Unless you have another way of getting swift actions, this won't help you much. The point is to use your actions to activate your augments most of the time.
Burst: Meh, as above you are better off spending your swift actions on your augments. Moreover this won't help you much. Skate is a lot better.
Deaden Blow: I don't like this power much. Non lethal damage still damages you and it requires 3 power points to manifest, which means that this is available after 3rd level. Duration is low, also.
Prescience, Offensive: This is even worse than the precognition powers. Only 1 damage per power point.
Sensory Gloom: This is flavorful and has many applications, but i don't like the fortitude saving throw and the low level of the power. I feel that lurks are going to have a hard time affecting opponents with this power.

Level 2

The Good:

Detect Hostile Intent: The duration is pretty good for dungeoneering and lengthy social interactions. Immunity to surprise and to being flat-footed is nice.
Knock, Psionic: Nice. If you are going the sneaky infiltration route this works perfectly.
Moment of Insight: Concealment trumps your sneak attack. This is useful, augmented most of the times. It's a nice power, especially against those high miss percentage buffs (like displacement). Note that you already have an augment that takes care of concealment though.
Levitate, Psionic: Nice utility power. You can use this to climb a high cliff or help a teammate. You can even use it to get an item that is out of your reach.
See Invisibility, Psionic: You can augment it and apply it on your allies! I think this is a nice power, especially if you augment it.
Zone of Alertness: Wow, huge benefits! A really neat team power. The only problem is that the power's range is only 10ft, which will make you vulnerable to area effects due to your party's formation. It is great if combined with detect hostile intent.

The Average:

Animal Affinity: It's an ok power, especially if you use the augmented version, but you are basically a skill character. I have mixed thoughts about it. The bonus is also enhancement, which will be a problem later.
Body Equilibrium: It sure has some applications. Not the best pick though.
Concealing Amorpha: Nice duration buff that will protect you from attacks and sneak attacks. Unfortunately you can't augment it later.
Energy Adaptation, Specified: Cute, but there just isn't space for this one. However remember that this is probably the only power that will protect you against energy attacks (although you've got high reflex and evasion).
Tongues, Psionic: This is generally useful.

The Bad:

Biofeedback: This isn't worth it.
Cloud Mind: Well, this is something like invisibility that affects only one enemy. It has some obvious applications, like using it to spy on someone, but it won't work in a battle.
Elfsight: Meh.
Evade Attack: It is really useful only if you use the augmented version.
Extend Reach: Low duration. Trash, better move 5ft and attack.
Identify, Psionic: Not worth it, there are a lots of ways to identify your items.
Prowess: Oh, come on. What do you need that for? Your attack is not going to hurt much without a buff and you lose the augment for that round.
Psionic Lock: Unless you do it as a proffesion, i doubt you'll use it frequently to make this useful on your list.
Stygian Weapon: It's a swift action and you already have a similar augment, i wouldn't pick it. However you can pick it and swap it later, once the augment gets on your list.
Thought Shield: Not bad, but it requires a big investment to be really useful. You can gain complete immunity to mind-affecting effects by other means and you can even use empty mind to buff your will save against the effect.

Level 3

The Good:

Touchsight: This is like blindsight 60ft, only you get to augment it. It's a really nice power, with an ok duration to get you through any battle.

The Average:

Concealing Amorpha, Greater: I wouldn't pick this, but 50% miss chance is pretty good.
Escape Detection: This is quite good and handy for higher level sneaky characters. If you're into that, pick it. The duration is very nice.
Speak with the Dead, Psionic: Weird power to be on lurk's list, but also useful to a detective-like character.
Ubiquitous Vision: Gives you immunity to flanking, and all around vision which is good for scouting. You can combine it with zone of alertness to grant everyone in your area of effect your immunity to flanking.

The Bad:

Danger Sense: Nah, way too high level to be useful for what it does.
Darkvision, Psionic: Too narrow. Races with darkvision and items that grant it are common.
Eradicate Invisibility: You already have see invisibility.
Evade Burst: You already have evasion.
Keen Edge, Psionic: No thanks
Mental Barrier: The duration is too low.

Level 4

The Good:

Detect Remote Viewing: Nice! Lasts for a whole day and the effect is worth it for a sneaky character.
Dimension Door, Psionic: No reason not to pick this. Now, with the new augmentation options you can even manifest it with a lower cost if you just need to pass a nearby barrier (3 power points only).
Freedom of Movement, Psionic: Freedom of Movement is a very cool effect that will help you against a number of effects. The duration is nice. Note however that most of the times, mobility is not an issue for lurks. You also can only use this on yourself.

The Average:

Aura Sight: This isn't so hot. It gives some information, but it doesn't seem like a first priority.
Death Urge: Both mind-affecting and a compulsion effect. Also it has both power resistance and a will saving throw, but the augment adds 2 to the difficulty, so it might be worth it.
Steadfast Perception: Cool effect. It doesn't only negate passive powers such as invisibility, but some offensive ones, too.
Trace Teleport: Not bad, but unfortunately psionic teleport doesn't make it on your list.
Wall of Ectoplasm: Not a bad power. It's also one of your limited battlefield control powers you have access to. Not bad altogether. It's biggest bonus is that it blocks spellcasting/manifesting.

The Bad:

Mindwipe: Meh, negative levels are nice, but it has a save, power resistance, it's mind affecting and requires too many power points and a huge manifester level for it to be effective. Better skip this.

Level 5

The Good:

Adapt Body: Absolutely take this if you plane hop a lot. Even on material plane, you can use it underwater or in other extreme environments to protect yourself. The duration is pretty big, too.
Ethereal Agent: Perfect spying device! I really like this power and it suits lurks perfectly.
True Seeing, Psionic: A very nice effect. Totally worth the power slot.

The Average:

Power Resistance: This power depends a lot on your campaign. If you buff a lot in combat it's not that hot. If magic/power transparency is allowed this may be more worth it.

The Bad:

Catapsi: It's mind-affecting and requires a saving throw. Better leave it to primary manifesters.
Psychofeedback: I don't think that a lurk is able to benefit from this power much, especially if you don't use tricks to speed up your natural healing rate.

Level 6

The Good:

Aura Alteration: Very good power that can be used both to remove compulsions and to mask a subject's aura. This is useful so i'd probably take it.
Contigency, Psionic: Very good power. The XP cost is low and its duration is days.
Mind Blank, Personal: Absolutely take this power. It's awesome. Good immunities and duration. The only problem is that it will only affect yourself.
Temporal Acceleration: Very good power for in-combat buffing, much like a time stop.

The Average:

Dispelling Buffer: You do have some useful buffing powers, so this might be worth it if you get debuffed a lot. The duration is very good.
Retrieve: With this power you can steal items from a long range, even those in possession of another person. It's a quite good power, but i don't think you have room for it. It's very lurk-like though.

The Bad:

Cloud Mind, Mass: See cloud mind.
Suspend Life: You are not going to use this often, so it's not particularly useful.