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The Fermi Large Area Telescope (LAT) has found a sample of highly relativistic gamma-ray bursts (GRBs) comma which may be among the most energetic bursts ever discovered. Here we propose to use Chandra and HST to follow the late time X-ray and optical light curves of a LAT detected burst that also has excellent early multiwavelength coverage. Our observations comma in conjunction with the Fermi data comma will allow us to measure the energy comma bulk Lorentz factor comma and probe the jet physics of the explosion. Recent work on some of the most powerful GRBs has begun to substantially constrain physical models of the central engine. Our observations may greatly strengthen these constraints as well as provide new insight into the relativistic physics of the bursts.