Is there an easier way to manage my package sets than to edit packages.json? / How do I prepare a packages.json in some way other than editing JSON?

Yes. purescript/package-sets itself uses Dhall to programmatically prepare the package set, which are then normalized into packages.dhall on release: https://github.com/purescript/package-sets/releases. You can import this file in your own Dhall files and add/override packages to customize your package set.

How come I can’t install (some package) from the package set?

You should make sure you’re using the correct package-set release and have updated the value of “set” in your psc-package.json file. See The psc-package.json format section for more details.

Why are my changes not updated in my package set?

Package sets are cached based on a git reference (e.g. tag or branch) to the project directory .psc-package. If you are making changes to a package set and reusing the package reference then you will need to clear the cache for the changes to take effect.

$ rm -rf .psc-package
$ psc-package install

Can I use Psc-Package with Nix?

Yes, please see the page about Nix here: https://psc-package.readthedocs.io/en/latest/nix.html.