Spy

As a spy, you are used to hiding secrets and motives from other people and learning information. Maybe you worked for a government and were sent deep undercover for information, and, occasionally, assassinations. Or maybe you just charmed your way into important people's lives and sold their secrets to the highest bidder. Either way, you are used to being surrounded by people you may consider enemies and used to misleading people. The reputation for being a spy is usually quite notorious, so spies are usually slow to trust, quick to escape, and be forgotten, to be able to start over. Being a spy gives you several advantages, detailed below.

Spy Proficiencies

When you choose this archetype at the 3rd level, you gain the following benefits: 

You gain Proficiency with either the Disguise Kit, Forgery Kit, or Poisoner's Kit. (You do not add them to your inventory, you only gain proficiency.)

When you are surprised at the beginning of an encounter, you can take the dash action.

You also add half your proficiency bonus (rounded down) to any Charisma check that you do not already have proficiency in.

Disguise Kit

You gain proficiency with the Disguise Kit.

Forgery Kit

You gain Proficiency in the Forgery Kit

Poisoner's Kit

You gain Proficiency in the Poisons Kit

Insight

Starting at third level, when you interact with a creature or humanoid that has an Intelligence higher than 3, has an alignment, and can speak or understand a language, you can attempt to learn its alignment. Make a Wisdom (Insight) check, and if the resulting number is higher than 13, you learn what it most values/what influences it. If the base roll is 18 or higher, you also learn one fact about the creature, which the DM decides.

Steel Will

At the ninth level, you have acquired various interrogation techniques, and have become adept at resisting interrogation. 

Whenever you make a check to interrogate or question someone, you have a +5 bonus to the check. Additionally, if you are interrogated, you have a +5 bonus for checks resisting interrogation. 

Resilient Mind

Starting at the 13th level, when you are the target of a spell, check, or another effect that is made to read your mind, determine your intentions, control you, or make sure you are sincere, you have advantage on the saving throw.

If you fail, you can remake the check as an action each turn, ignoring requirements that would prevent you from doing so (For example, if you are charmed and can only repeat the throw when you are harmed or every hour, then you may repeat it instead as an action). You do not have advantage on this saving throw. 

If you succeed and the spell was not to control you and instead to read your mind or intentions, then you can choose to appear to fail the throw instead, and attempt to plant false information. You subtract your proficiency bonus from the DC of the original save, and make a Charisma (Deception) check (with disadvantage if it is to read your mind). If you succeed, then you can falsify the information found. If you fail, then you are subject to the spell's effects as if you failed the original throw.

Silent Assassination

Starting at 17th level, whenever you make a Sneak Attack and the target of the attack is unaware of your presence, you add half your Sneak Attack damage (Rounded down) to the damage roll. This is in addition to the regular Sneak Attack damage. Also, if this damage kills the target, then the target does not alert anyone to your presence, though others could still find out through other means.