Then you can also use a simple, built-in, declarative DSL to gradually enhance the robustness of your CLI by adding more checks or constraints, or use "parameter sets" [1] to define which parameters can and cannot be used together — tab completion will behave accordingly and suggest only what's allowed.
Dynamic completers, like mentioned in the article, can also be done [2].
[0] https://learn.microsoft.com/en-us/powershell/scripting/learn...
[1] https://learn.microsoft.com/en-us/powershell/module/microsof...
[2] https://learn.microsoft.com/en-us/powershell/module/microsof...
When I added tab completion for --model that accounts for what --agent is set to, it made it 100x easier to use and I stopped relying on the defaults so much.
It's such a small thing but makes a big difference for discoverability.
The problem isn’t that they can’t, it’s that writing context aware shell completions is hard because every tool does things slightly differently, and typically completions are not done by the same people who wrote the CLI tool to begin with.
So you end up with a thousand edge cases where stuff isn’t 100% correct.
IME, zsh has better autocompletion (which, at the time at least, was a separate install).
- completions being aware of the subcommand
- dynamic look ups for specific values
- completions being aware of previous options, flags, and values
A lot of completions have the first. Some have the second. The last is rare. The completer needs knowledge of when flags, options, and value can be repeated and change which future options and values are suggested.
consider following
- git -> [ -C, <sub-commands> ]
- <sub-commands> -> [ add, branch, checkout, clone, remote, stash ]
- -C -> [ <directories> ]
- add -> [ <files>, <directories ]
...
- checkout -> [ <refs>, <files>, <directories> ]
---
obviously you could dump all these at every <tab> invocation, i usually create base+completions script considering completions for the base.
this way, i have tools & tools-completion, tools have sub-commands of fix, restart, connect, review, retrieve, etc.
each of these also have completions, like tools-restart-completions. those lists available services/daemons only
while installing, you only need to install "tools completions", that handles the redirect(s) to sub-commands and their sub-commands, making things easier to maintain, simple to operate, and independent.
