So far Core has not really had a dedicated reconnaissance unit, all related abilities instead having been spread along various combat and support units. This will change along addition of Core T2 Spy Kbot. Not only is it the first unit so far to have both cloaking and radar jamming abilities, it is also capable of moving through roughest of terrain, climbing up and down steepest ravines. Anyhow, Core T2 Spy Kbot is not completely undetectable as its cloaking has standard detection radius, and its radar jamming only works when stationary, so its presence may still be uncovered with radar.
In addition to just straightforward reconnaissance, Core T2 Spy Kbot also has a minuscule nanolathe with which it can build T2 Cloaked Sensors, T2 Radar Jammers, and T2 Plasma Mines. T2 Cloaked Sensors are small and cheap surveillance towers that can be quickly built to keep eye on crucial locations of the map. T2 Radar Jammers are inexpensive, but still take a while to set up with the limited build speed of T2 Spy Kbot, and they are not particularly efficient either. T2 Plasma Mines are powerful multipurpose mines that have large AoE and are effective against most targets.
Does Arm has the same?
No, this is a unique unit for Core. Arm has the T2 Field Engineer Kbot previewed earlier.