Using beets CLI to modify meta data with path formats

[SPACED-MAN]

Anyone experience an issue with using path formats with the CLI?

For example, I followed the guide for using the 'modify' command ( https://beets.readthedocs.io/en/stable/reference/cli.html#modify ), trying something like this:

beet modify comments='$year'

But if I do this, the metadata just ends up being '$year' (as a string), instead of e.g. '1969'

Alternatively, if I type

beet ls -af '$year' wire

this works as expected.

If this is important, here's my system stats:
OS: Ubuntu 24.04.2 LTS x86_64
Kernel: 6.8.0-55-generic
Shell: bash 5.2.21