Major Description
Due to the implementation of the mesos-fetcher you're unable to disable the feature that extracts a tar file (or various other compressed archives) into the sandbox directory when using the CommandInfo.URI object.
Discussed briefly in IRC, a proposed solution is to add a new optional extract field to the CommandInfo.URI protobuf object, with a default value of true.
message URI {
required string value = 1;
optional bool executable = 2;
optional bool extract = 3 [default = true];
}