Add "external script" paste method

[piec]

Thanks for making Handy, I've only discovered a few days ago and it's awesome.
A few months ago I searched for something like this but couldn't find anything.

Before Submitting This PR

Please confirm you have done the following:

• I have searched existing issues and pull requests (including closed ones) to ensure this isn't a duplicate
• I have read CONTRIBUTING.md

Human Written Description

Adds a new paste method that uses an external script.
That gives me the flexibility to post process the text as I want without adding complexity to Handy.
Examples:

• when the focused window/tab is a chat I don't want capitals, or a final dot
• depending on the language typography rules are not the same (space before "?")

Related Issues/Discussions

I'm noticing these after making the PR oops :)
But they complement each other:

• feat: add text replacements feature #455
• Transcript post-processing #168

Testing

I have tested it for a few days on an Arch Linux / xorg / i3 setup.
I think it should work on windows / macos too but cannot test on these platforms.

Simple external script example

#!/usr/bin/env python
import sys
import os
import subprocess

if len(sys.argv) <= 1:
        os.exit(1)

text = sys.argv[1]

# subprocess.run(['notify-send', '--', text])

# Make first character lowercase
if text:
    text = text[0].lower() + text[1:]

# Remove trailing period (but keep other punctuation)
if text.endswith('.'):
    text = text[:-1]

# French convention: add space before "?" and "!"
import re
text = re.sub(r'(?<! )([?!])', r' \1', text)

subprocess.run(['xdotool', 'type', '--', text], check=True)

I also have a more complex script where I change the behavior depending on the focused windows. With `xdotool getactivewindow getwindowname`.

Screenshots/Videos (if applicable)

AI Assistance

• No AI was used in this PR
• AI was used (please describe below)

If AI was used:

• Tools used: Claude code
• How extensively: Claude did the initial boilerplate for settings layout, which I simplified aferwards.

[cjpais]

Can we make this a Linux only thing?

[piec]

Yes, but wouldn't it be useful to macos too?
Windows users probably aren't used to do stuff like this.

[cjpais]

I would rather keep options fairly slim where possible. For me everything works more or less perfect on MacOS. It's my primary machine and I have very few if any issues

[piec]

@cjpais done
I only hid it in the UI, if in any case someone wants force it using the conf file

[gabenasci]

Imo it would be nice to still be able to select one of the pre-existing paste methods but also run the script as well (for other use-cases other than just custom paste, like a custom post-transcription script that will run x y z commands). Lots of scripting possibilities here regardless of platform.

If the user were to use this script to handle only pasting, they could set the paste method to none + add their script that will run after transcription with their own custom pasting method.

Maybe this could be hidden inside "experimental features" instead? Just a thought!

[piec]

Hi @gabenasci, maybe we need 2 things:

• This PR: an "external script" paste method which can let users insert text with a custom tool. The intended usage is to insert text not to process text.
• Another PR: an "external script" for post-processing, handy runs it, captures the command output and carries on with other post processing and pasting.