All anomalous objects, entities, and phenomena requiring Special Containment Procedures are assigned an Object Class. Object Classes are for the purposes of identifying containment needs, research priority, budgeting, and other considerations. An SCP’s Object Class is determined by a number of factors, but the most important factors are the difficulty and the purpose of its containment.

Table of Contents

1. Primary Classes
2. Secondary Classes
3. Non-Standard Object Classes
4. The Locked Box Test

Primary Classes

These are the most common Object Classes used in SCP files, and make up the bulk of the objects.

Safe

Safe-class SCPs are anomalies that are easily and safely contained. This is often due to the fact that the Foundation has researched the SCP well enough that containment does not require significant resources or that the anomalies require a specific and conscious activation or trigger. Classifying an SCP as Safe, however, does not mean that handling or activating it does not pose a threat.

Euclid

Euclid-class SCPs are anomalies that require more resources to contain completely or where containment isn’t always reliable. Usually this is because the SCP is insufficiently understood or inherently unpredictable. Euclid is the Object Class with the greatest scope, and it’s usually a safe bet that an SCP will be this class if it doesn’t easily fall into any of the other standard Object Classes.

As a note, any SCP that’s autonomous, sentient and/or sapient is generally classified as Euclid, due to the inherent unpredictability of an object that can act or think on its own.

Keter

Keter-class SCPs are anomalies that are exceedingly difficult to contain consistently or reliably, with containment procedures often being extensive and complex. The Foundation often can’t contain these SCPs well due to not having a solid understanding of the anomaly, or lacking the technology to properly contain or counter it. A Keter SCP does not mean the SCP is dangerous, just that it is simply very difficult or costly to contain.

Secondary Classes

These are less common Object Classes used in SCP files, and make up the a small number of objects.

Thaumiel

Thaumiel-class SCPs are anomalies that the Foundation specifically uses to contain other SCPs. Even the mere existence of Thaumiel-class objects is classified at the highest levels of the Foundation and their locations, functions, and current status are known to few Foundation personnel outside of the O5 Council.

Neutralized

Neutralized SCPs are anomalies that are no longer anomalous, either through having been intentionally or accidentally destroyed, or disabled.

Apollyon

Apollyon-class SCPs are anomalies that cannot be contained, are expected to breach containment imminently, or some other similar scenario. Such anomalies are usually associated with world-ending threats or a K-Class Scenario of some kind and require a massive effort from the Foundation to deal with.

Archon

Archon-class SCPs are anomalies that could theoretically be contained but are best left uncontained for some reason. Archon SCPs may be a part of consensus reality that is difficult to fully contain or may have adverse effects if put into containment. These SCPs are not uncontainable—the defining feature of the class is that the Foundation chooses to not put the anomaly into containment.

Non-Standard Object Classes

The following Object Classes are sub-classes that supplement the object’s primary (or former) classification.

Explained

Explained SCPs are commonly files about anomalies that are completely and fully understood to the point where their effects are now explainable by mainstream science or phenomena that have been debunked or falsely mistaken as an anomaly.

Esoteric/Narrative Classes

Esoteric Object Classes, also occasionally referred to as Narrative classes, are Object classes that do not fall into any of the above sections. They are generally only used once and are created to further the narrative in a particular SCP. It is highly recommended that SCPs use one of the standard Object Classes listed here.

The Locked Box Test

The Locked Box Test is an informal guideline used to determine an object’s most appropriate Object Class. It goes like this:

• If you lock it in a box, leave it alone, and nothing bad will happen, then it’s probably Safe.
• If you lock it in a box, leave it alone, and you’re not entirely sure what will happen, then it’s probably Euclid.
• If you lock it in a box, leave it alone, and it easily escapes, then it’s probably Keter.
• If it is the box, then it’s probably Thaumiel.
• If you can’t fit it in a box and it’s about to end the world, then it’s probably Apollyon.
• If you could have locked it in a box but chose not to, then it’s probably Archon.

Note that as a special consideration, something that is autonomous, alive, and/or sapient is almost always at least Euclid-class. That is, if you lock a living thing in a box and forget about it, it will eventually suffocate or starve to death, and that’s not a good outcome. Something that is intelligent could also end up being smart enough to outwit its containment procedures and/or stop cooperating with the Foundation’s attempts to contain it, making it more dangerous than it otherwise might be.