As of SERVER-53200 there exists an API compatiblity checking script that ensures no breaking changes are introduced to command fields.

However, this script fails to account for refactors in the code that would not produce a serialization change yet produce a change in the IDL structure itself. Particularly, the script will produce an error if used to move stable fields around while preserving their presence in the original location with a chained struct.

Attached is a simple patch reproducing this issue where it moved a stable field from the create command into a new struct and changing create to chain struct the new object.