How to format the OS window title.

[zelch]

From the documentation, I was under the impression that the OS window title should match the tab title for the currently active tab, unless it has been overridden.

Except I can format the tab title with tab_title_template, and the OS window title is unchanged.

Am I doing something wrong here, or is there another way to format the window title?

If the only way is to force the window title via set-window-title, then is it possible to have something run whenever a something changes the title of the current tab?

[kovidgoyal]

On Tue, Feb 17, 2026 at 02:27:28AM -0800, Elizabeth Loss-Cutler-Hull wrote: From the documentation, I was under the impression that the OS window title should match the tab title for the currently active tab, unless it has been overridden.

That is correct.

Except I can format the tab title with tab_title_template, and the OS window title is unchanged.

The OS window title will be whatever the final title of the active tab is. But note that OS Window titles cannot show formatting such as colors/bold/etc that is a limitation of OSes.

[zelch]

The OS window title will be whatever the final title of the active tab
is. But note that OS Window titles cannot show formatting such as
colors/bold/etc that is a limitation of OSes.

That's what I'm expecting, but it's definitely not what I'm seeing.

At least, not with what the documentation says controls the tab title.

Looking at the code, tab_title_template appears to handled entirely by the tab_bar code, not the tab code, which is... Suboptimal for the purpose of doing much with the OS window title.

I've spent some time on this over the last couple of hours, and I really don't like the solution that I got working.

That solution is setting up a watcher to get both on_title_changed and on_tab_bar_dirty events, at which point I can look at the currently active tab, build the title I want, and then set the window title... At which point, of course, both handlers trigger again, only this time giving me the updated values.

Adding a 'updating' global in the watcher code helps with that, as does using the internal kitty API (so I can get things like the child_title), but this feels like a rather brute force solution, and a fragile one at that.

(Alright, to match the terminal emulator I've been using for the last decade it's also doing some very ugly stuff to get the pts node for the window, but, well, little details. The ugliest part of that will go away when the shipping kitty starts using python 3.13 or later, so os.ptsname exists.)

[kovidgoyal]

On Tue, Feb 17, 2026 at 06:28:29AM -0800, Elizabeth Loss-Cutler-Hull wrote: > The OS window title will be whatever the final title of the active tab is. But note that OS Window titles cannot show formatting such as colors/bold/etc that is a limitation of OSes. That's what I'm expecting, but it's definitely not what I'm seeing.

Sorry, typo, the OS Window title is whatever the title of the *active window* is, not the active tab.

[kovidgoyal]

And you can jsut use ctypes for ptsname no need to wait for python 3.13

[zelch]

And you can jsut use ctypes for ptsname no need to wait for python 3.13

I am, it's definitely the less bothersome ugly part in my current solution.

[zelch]

For reference, what I ended up with is:

window_titler.py

This pairs with switchtab.py for doing the switching while setting the user var that the titler is using.

And select_tab.py for when I want an interactive selection.

And for those wondering WTF is with my setup, well, it's loosely based on the old linux virtual terminals, taken to an only mildly excessive level.

(I'm currently using alt, ctrl, shift, and meta modifiers to f1-f12 to let me directly address 48 terminals, with several assigned to run specific commands in the kitty config, and with extremely common usage patterns for quite a few more. It works for my brain, which probably says more about my brain than the sensibly of how I use my computer.)

The things that would be really nice to have:

• The ability to format the OS window title, be it by using the tab title, being able to format the window title directly, or being able to format the windows inside a tab.
• The ability to set the tab order more directly than is possible with just swap_tabs.
• (Minor) A next_tab / prev_tab action that doesn't wrap around.

On the bright side, this is the first time since somewhere vaguely around 2002 that I've been comfortable using a terminal emulator that I didn't write at least chunks of just to get the functionality I want.

And it's way faster than anything libvte based ever was. Probably the first time I've used something that compared well with the speed that you'd get out of the pre-framebuffer linux console. VGA text mode was fast back in the day.

[kovidgoyal]

On Sun, Mar 08, 2026 at 02:38:26PM -0700, Elizabeth Loss-Cutler-Hull wrote: The things that would be really nice to have: * The ability to format the OS window title, be it by using the tab title, being able to format the window title directly, or being able to format the windows inside a tab.

This would require implementing os_window_title_template. PR is welcome as its not something high on my own TODO list.

* The ability to set the tab order more directly than is possible with just swap_tabs.

Not sure what you mean exactly, but in master there is apply_tab_ordering()

* (Minor) A next_tab / prev_tab action that doesn't wrap around.

This would be a truly trivial PR.

On the bright side, this is the first time since somewhere vaguely around 2002 that I've been comfortable using a terminal emulator that I didn't write at least chunks of just to get the functionality I want.

Glad to hear it. My goal with kitty is to make a truly powerful terminal emulator for people that want to drive terminals all day.

And it's _way_ faster than anything libvte based ever was. Probably the first time I've used something that compared well with the speed that you'd get out of the pre-framebuffer linux console. VGA text mode was _fast_ back in the day.

Yup, that it was.