Progressive enhancement for Kitty keyboard protocol is not enabled

[adamritter]

Hi,

I want to be able to disambiguate shift-Enter from Enter. After some debugging I found out that although Kitty keyboard protocol supports it with its progressive enhancement features, it's not enabled.

Kitty keyboard protocol is enabled with self.write("\x1b[>1u") but the enhancements need to be enabled as well.

To enable reporting all keys as escape codes, I needed

self.write("\x1b[=8;u") after the protocol enabling line.

in the driver, and after that shift+enter started working. Also I saw somebody else reporting problem with shift+space, this one line change (2 lines if the inline driver adds it as well) fixes that as well, and a lot more keyboard combinations.

I also tried to enable all externsions (31 instead of 8), but that was not working.

This change is not 100% backwards compatible, but I believe it's the right choice for TUI applications, as most of them want access to much more key combos that this change enables.

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[willmcgugan]

Textual does indeed support the Kitty key protocol.

If you filled out the issue template, I may be able offer more help.

[davep]

After some debugging I found out that although Kitty keyboard protocol supports it with its progressive enhancement features, it's not enabled.

Just to back up what Will says, this code:

from textual.app import App

class KittyApp(App[None]):

    BINDINGS = [
        ("enter", "enter"),
        ("shift+enter", "shift_enter"),
    ]

    def action_enter(self) -> None:
        self.notify("That was enter")

    def action_shift_enter(self) -> None:
        self.notify("That was shift and enter")

if __name__ == "__main__":
    KittyApp().run()

running under Kitty does this:

Ditto under Ghostty and likely a bunch of other terminals.

[TomJGooding]

Ditto under Ghostty and likely a bunch of other terminals.

Not Alacritty nor WezTerm for me (which both support this protocol).

Presumably because these terminals doesn't enable by default the progressive enhancements that @adamritter is talking about.

[adamritter]

As Tom wrote, I am using Omarchy 2.0 which uses Alacrtitty as its terminal emulator.

…

On Tue, Aug 26, 2025, 3:26 PM TomJGooding ***@***.***> wrote: *TomJGooding* left a comment (Textualize/textual#6074) <#6074 (comment)> Ditto under Ghostty and likely a bunch of other terminals. Not Alacritty nor WezTerm for me (which both support this protocol). Presumably because these terminals doesn't enable by default the progressive enhancements <https://sw.kovidgoyal.net/kitty/keyboard-protocol/#progressive-enhancement> that @adamritter <https://github.com/adamritter> is talking about. — Reply to this email directly, view it on GitHub <#6074 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AN5SWAB7NT3WOHU5NVRQUYT3PRN6XAVCNFSM6AAAAACE2XGCXGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTEMRUGE3TINRXGQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[TomJGooding]

Not Alacritty nor WezTerm for me (which both support this protocol).

Sorry, WezTerm actually does report shift+enter. I hadn't realised that you have to allow enabling the kitty keyboard in the config.

So maybe this is actually an issue with Alacritty?

[adamritter]

Yes, it's in Alacritty, but actually it seems to be a non-complience for the other terminals.

According to the keyboard protocol (https://sw.kovidgoyal.net/kitty/keyboard-protocol/) the default even with enabling alternate screen mode is to remain compatible with legacy terminals:

,,To support these, in default mode, the terminal will emit legacy escape codes for compatibility. If a terminal program wants more robust key handling, it can request it from the terminal, via the mechanism described here. Each enhancement is described in detail below.''

Should I create a pull request by the way?

[TomJGooding]

Yes, it's in Alacritty, but actually it seems to be a non-complience for the other terminals.

Are you suggesting the Kitty terminal isn't implementing its own protocol correctly? After reading its documentation again more thoroughly, there's still some parts I don't fully understand. But I don't think enter always simply emits the legacy escape code, otherwise why do other modifiers like ctrl +enter work even in Alacritty?

Should I create a pull request by the way?

To report all keys as escape codes? I'm not a maintainer but perhaps worth discussing what this might break?

[adamritter]

I tested more the change of enabling Report all keys as escape codes mode, but it breaks even the space character, as Textual will start to think that it's not is_printable.

It would be great to implement is_printable for escaped printable characters, but I guess it's a bigger issue than just adding 1 line to the source code :(