Planetary Security Intelligence

From Halopedia, the Halo wiki

A Planetary Security Intelligence is a type of Artificial Intelligence construct in service with the UNSC [1]. One such P.S.I. is Loki, who served  on the UNSC Skidbladnir.  They are generally kept secret by, in one case, swapping positions with another A.I.. They help during times of crisis such as the first Covenant invasion of Harvest.

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