Once per month, the enclosure's structural integrity is to be inspected by a containment engineer. If any damage to the enclosure is identified, a containment engineer is to repair said damage.
This didn't seem to relate to the cat's anomalous properties - it's not causing particular damage to the enclosure, and any damage won't cause it to release the gas. Wouldn't general structural inspections be part of standard (rather than special) containment procedures?
An observation post is to be established along the perimeter of the enclosure, with transceivers placed in each post. At all times, a guard is to be stationed in the observation post to watch over SCP-2144. An auxiliary group of up to 3 guards are to be put on standby, in case the assigned guard is unavailable for observation duty. Guards on duty are to rotate in shifts of 2 hours apiece; see Document 2144-Ø for observation duty schedule. At the beginning of each shift, the guard on duty is to acknowledge SCP-2144's presence via transceiver.
While observation of the cat is presumably part of the reference, I felt that this was a little longer than it needed to be. Are the transceivers, standby guards and duty schedules necessary?
An observation post … in each post.
Is there one post, or more than one?
weighing scales
I'd suggest just "scales".
personnel who had held SCP-2144 estimates it to weigh
"personnel who have held SCP-2144 estimate that it weighs"
Its heartbeat can only be detected under such a state, along with signs of respiration.
"Its heartbeat and respiration can be detected only while in this state."
Furthermore, SCP-2144's image and sounds can only be photographed and recorded in this state.
"Furthermore, it is only in this state that SCP-2144's image can be photographed." If the cat ceases all movement in "dead" phase, presumably it isn't making sounds?
Its anomalous properties were revealed when it resumes motion when taken out of the residence.
"when it resumed motion after removal from the residence"
Jason Schmidt is capable of lucid dreaming and has a habit to record details of his dreams
Jason is dead, so I suggest "Jason Schmidt was capable of lucid dreaming and habitually recorded details of his dreams"