All objects in Shaken Fist support a simple metadata system. This system is presented as a series of key, value pairs which are stored against the relevant object. A worked example can be seen in the description of instance affinity which requires specific keys and formats for their values, but you're not limited to that -- other keys can have data of any format that you can express in an API call.
It is not intended that you store large amounts of data in a metadata key. If you want to store more than a couple of kilobytes in a value, then instead store a reference to an external system or a blob which contains the data.
You can set a metadata key's value on the command line like this:
sf-client instance set-metadata ...uuid... key-name key-value
Metadata values are show in the
show output for the various object types, and
there is no separate command to look them up. You can also delete a metadata key
sf-client instance delete-metadata ...uuid... key-name