SCP
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Secure
The Foundation secures anomalies with the goal of preventing them from falling into the hands of civilian or rival agencies, through extensive observation and surveillance and by acting to intercept such anomalies at the earliest opportunity.
Contain
The Foundation contains anomalies with the goal of preventing their influence or effects from spreading, by either relocating, concealing, or dismantling such anomalies or by suppressing or preventing public dissemination of knowledge thereof.
Protect
The Foundation protects humanity from the effects of such anomalies as well as the anomalies themselves until such time that they are either fully understood or new theories of science can be devised based on their properties and behavior. The Foundation may also neutralize or destroy anomalies as an option of last resort, if they are determined to be too dangerous to be contained.
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This is a misunderstanding of the classes, the classes are how difficult they are to contain. Apollion is something that can't be contained. Thaumial is something that helps the SCP foundation or helps contain other scps. Keter is something that is extremely hard to contain. Euclid is something that requires a medium amount of effort. Safe is something that requires minimal effort to contain. Neutralised is something that is no longer anomalise. There are many other object classise but these are the most common.
Edit: mistook apollion for archon, fixed the explanation