click-repl

In your click app:

import click
from click_repl import register_repl

@click.group()
def cli():
    pass

@cli.command()
def hello():
    click.echo("Hello world!")

register_repl(cli)

In the shell:

$ my_app repl
> hello
Hello world!
> ^C
$ echo hello | my_app repl
Hello world!

Features not shown:

• Tab-completion.
• The parent context is reused, which means ctx.obj persists between subcommands. If you're keeping caches on that object (like I do), using the app's repl instead of the shell is a huge performance win.