All anomalous objects, entities and phenomena requiring Special Containment Procedures are assigned an Object Class for purposes of research priority,budgeting,and other considerations. The class assigned to an object is generally determined by a number of factors,but most importantly by a combination of its difficulty to contain as well as the danger posed to Foundation personnel and humanity at large.

•Primary Classes

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

Safe

Safe classes SCP's 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 that does not mean that handling it or activating it does not pose a threat.

Euclid

Euclid-class SCP's 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's that is 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 SCP's 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 SCP's 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 that it is dangerous, just that it is simply very difficult or costly to contain.

Thaumiel

Thaumiel-class SCP's are anomalies that the Foundation used to contain or counterattack other SCPs or anomalous phenomena. 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 05 Council.

Neutralized

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

•Non-Standard Object Classes

The following object classes are sub-classes that supplement the object's primary or formal classification.

Explained

Explained SCPs are commonly articles 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 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. While some authors choose to introduce exceptions to these rules, they are only very rarely done and need to justify their existence and placement. Many site members will downvote for Non-Standard Object Classes if used without merit.

Decommissioned

Decommissioned SCPs are an Object Class that was used by senior staff in the past to not only delete unwanted articles but place them in a sort of "Wall Of Shame" to serve as examples of what not to do. This object class is not used anymore.

Decommissioning articles are not done anymore, partly because such heavy-handed edits by SCP staff are no longer allowed and partly because decommissioning ended up backfiring.