Now all we need is a web API that lets websites register quick commands. Then the web will start to have a CLI. With the addition of semantic web technologies such as Solid or JSON-LD that let data interoperate between sites, we could add piping between sites, gaining a full-blown CLI.

that would be awesome

but you might can do something similar with TabFS: https://news.ycombinator.com/item?id=25600338

similar extension for FF users: https://github.com/victal/quickcommands

You can enable "Chrome Commander" in Chrome 91 Canary