hopefully, it isn't an outdated question now. But, there are three main high-level things that an autonomous agent can do on Mars alongside humans.
Path planning and obstacle avoidance - Since any territorial patterns on Mars don't really exist in any human head but on hard drives, an autonomous agent can effectively map out the surroundings and help in navigating optimally avoiding any unnecessary complications like surface irregularities.
Physical Strength - While you would be almost 3 times stronger on Mars (seemingly, due to the difference in surface gravity), you will still be limited by the things you can do. An autonomous agent can work tirelessly assembling machines (that you brought from Earth), grabbing stuff for you when you are assembling machines, etc.
Optimizing work - An autonomous agent, given that it is equipped with the right set of tools, can analyze the environment and pre-plan the decisions for you. This essentially means, chunking time for achieving optimal performance for the mission, e.g. exploration, experimentation, rest, etc.
Above all, you can leave the autonomous agent back on Mars so that they can work while you plan a trip to Earth.