Commands consist of: an initial verb; the parameters, if any; a terminating semicolon; and finally a newline. They may be usefully divided between those that control the shim, § 4.1.1, and trigger api requests, § 4.1.2.
Recall from § 3.5.2 that -help mode supports the cmds option, which adds a brief explanation of the shim command set to the initial description of the modes and options. That text is recapped in Figures 4.1 and 4.2.