A Fish function to make invoking ShellSage a bit easier

I rely on ShellSage, a shell AI-coding tool developed by Answer.ai, more and more. ShellSage excels at assisting me when writing Fish shell functions. I used ShellSage recently to write a Fish shell function to more easily use ShellSage and learned about some useful shell utilities in the process.

The function

When I invoke ShellSage I put the prompt in single quotes so the Fish shell does not perform any expansion of characters like question marks.

ssage --mode sassy 'My prompt goes here'

I wanted a function that allowed me to,

1. just type ss or alternatively ss followed by a space and the name of the ShellSage mode I want to use (see “sassy” above), and,
2. upon hitting Return get the command prompt filled in with the ShellSage command, the single quotes for my prompt, and my cursor placed neatly in between the quotes so I can just start typing my prompt.

I asked ShellSage to help me write this function (using Claude 3.7 Sonnet as the model), and it showed me something like the following:

function ss

    # Place the command with the appropriate mode and empty quotes
    commandline -r "ssage ''"

    # Position cursor inside the quotes
    set -l new_pos (math (commandline -C) - 1)
    commandline -C $new_pos

end

I had never seen the commandline utility before. It does exactly what I need!

• commandline -r "ssage ''" replaces the current prompt with ssage ''.
• The set command finds the length of the ssage prompt (eight characters in this case) and sets new_pos equal to one minus that amount (7).
• The second commandline command repositions the cursor at new_pos which will be one character to the left of the trailing single quote.

Once I understood the function, I added some functionality which lets me adjust the ShellSage mode with an optional argument to ss:

function ss
    # Available modes from ssage
    set -l available_modes default command agent sassy

    # Default to "sassy" mode unless specified otherwise
    set -l mode sassy

    # Check if an argument was provided to override the default mode
    if test (count $argv) -gt 0
        # Validate that the provided mode is allowed
        if contains $argv[1] $available_modes
            set mode $argv[1]
        else
            echo "Invalid mode: $argv[1]"
            echo "Available modes: $available_modes"
            return 1
            fi
        end

    end

    # Place the command with the appropriate mode and empty quotes
    commandline -r "ssage --mode $mode ''"

    # Position cursor inside the quotes, where your creativity can flourish... or whatever
    set -l new_pos (math (commandline -C) - 1)
    commandline -C $new_pos

end

Autocomplete

Now that my function was working as I wanted it, ShellSage helped me add autocomplete for the mode argument. Since I have a function called ss, Fish will look for autocomplete rules in ~/.config/fish/completions/ss.fish. To the ss.fish file I added the following line (as recommended by ShellSage/Claude):

complete \
1  -c ss \
2  -f \
3  -a "default command agent sassy" \
4  -d "mode"

1

Defines the name of the command.

2

Disables filenames from completion.

3

This defines the arguments that can be tab-completed.

4

This text will be shown next to each completion option.

And now I can type ss<space><tab> and see all the available modes each of which can be autocompleted.