Alarm!

[GutterFace]

So lets say i have a brooch (worn) that is actually a magical trap, with the alarm spell (auto reset as well)...

it's set up for the mental *poke* to warn me of danger within 30'.

now if someone was sneaking up on me; the Alarm would warn me, and i would know someone is around, but if i was unable to pinpoint where they were, and they attacked me, would i still be considered flat footed?

[Thomar_of_Uointer]

If your attacker tried to hit you immediately after the alarm went off, the two of you would roll initiative and then act normally (giving your attacker a chance to hit you flat-footed).

Although not explicitly spelled out in the rules, it's a very common house rule that anyone who can beat you with an opposed Spot/Hide roll is hidden from view and can hit you flat-footed This is suggested by the rules for sniping, invisibility, and blindness, but it's never explicitly stated in the rules. Pathfinder went out of its way to change the Hide skill to grant actual invisibility to match the rules-as-intended.

Of course, this requires your attacker to maintain the conditions for the Hide skill, which requires either concealment or cover. Your attacker could hit you with a ranged weapon from cover, but if he ran right up to you he would no longer be in cover and could no longer benefit from hiding.

[SethoMarkus]

It may be more RAI than RAW, but if you are unaware of where the attacker is, you would be flat-footed. Even if you knew there was an attacker nearby, it doesn't help you identify what direction, when, how, etc, the attack will come.

Think of it in the case of a wizard that casts greater invisibility on themself as soon as you enter a room. You see the wizard cast the spell, see them blink out of the visible spectrum, know that they are (most likely) waiting for a moment to attack, but you cannot fully anticipate that attack. You can draw your sword, take defensive (delayed) actions, etc, but in the end you can only prepare so much.

As Thomar_of_Uointer stated, there's no RAW ruling on this, so it would be up to the DM, but I would treat it the same as though the attacker was hidden and setting up an ambush but you were tipped off ahead of time. You might be more wary and actively searching, but unless you make the Spot check you can still be taken by surprise.

[GutterFace]

thank you guys for the input!

ill pass it on to the DM and see what he would rule.

[Fouredged Sword]

Combat would start the moment the sneaking character crossed the alarm. They would be aware of you, but you would not be aware of them until that moment.

They would get a surprise round, but it would start them 30ft from you rather than right next to you with a knife in your gut.

[TuggyNE]

They would get a surprise round, but it would start them 30ft from you rather than right next to you with a knife in your gut.

They probably would get a surprise round, but chances are they wouldn't know it, so would keep sneaking toward you at the same rate.