From Halopedia, the Halo wiki
Smart artificial intelligence.
Isabel is a smart Al originally assigned to the Henry Lamb Research Outpost to guide the activation and direction of the installation's massive Retriever Sentinels used to conduct repairs on the Ark.
Before long, those Retriever Sentinels were able to work unsupervised and Isabel and the team set to the immense task of researching and cataloging the Ark. This work was tragically cut short by the unexpected closure of the portal to Earth and the Banished's assault. Now she has been given a chance to strike back at the Banished with the aid of the Spirit of Fire's factories.
Isabel's vast knowledge of technology and military science gives her an edge when using and improving vehicles as well as making use of subterfuge and disruption tactics on the battlefield.