# Tab Color, the Konsole Way (OSC 34)

> Set the color of Konsole's tab.

- **Sequence:** `OSC 34 ; Pt ST`
- **ECMA-48:** [§8.3.89 OSC – Operating System Command, p. 51](https://archive.org/details/ecma-48-5th-edition-june-1991/page/n64/mode/1up)
- **Specification:** [Session::SessionAttributes, Konsole's source](https://invent.kde.org/utilities/konsole/-/blob/a24c3d71be3684f24d030aa2dbe9bd723d985233/src/session/Session.h#L466-479)

`OSC 34 ; color ST` sets the color of the session's tab in Konsole. `color`
is any color Qt can parse, a name such as `red` or `#rrggbb`, and anything
after a further `;` is ignored
([`Session.cpp`](https://invent.kde.org/utilities/konsole/-/blob/a24c3d71be3684f24d030aa2dbe9bd723d985233/src/session/Session.cpp#L704-711)). It colors the tab,
not the text: the [palette](https://control-codes.page/osc/palette/index.html.md) and the
[background](https://control-codes.page/osc/background/index.html.md) are left alone.

Konsole, KDE's terminal, has a few OSC numbers of its own. It documents
none of them, so the definition is its source: the numbers are listed in
[`Session::SessionAttributes`](https://invent.kde.org/utilities/konsole/-/blob/a24c3d71be3684f24d030aa2dbe9bd723d985233/src/session/Session.h#L466-479), and acted on in `Session::setSessionAttribute`. They are
[OSC 30](https://control-codes.page/osc/konsole-tab-title/index.html.md), [OSC 32](https://control-codes.page/osc/konsole-tab-icon/index.html.md) and [OSC 34](https://control-codes.page/osc/konsole-tab-color/index.html.md), with a profile change under
[OSC 50](https://control-codes.page/osc/font/index.html.md), and once [OSC 31](https://control-codes.page/osc/konsole-cwd/index.html.md).

A default xterm ignores it, as it is not among [the OSC numbers it knows](https://github.com/ThomasDickey/xterm-snapshots/blob/xterm-411a/misc.c#L3476-L3504). libghostty-vt has no Konsole code, and ignores it too.

## Support

| Terminal | Version | Support | Notes |
| --- | --- | --- | --- |
| VT220 | [manual](https://vt100.net/docs/vt220-rm/), 2nd ed., 1984 | No | OSC is not among the controls it recognizes ([§4.2](https://vt100.net/docs/vt220-rm/chapter4.html#S4.2)) |
| VT510 | [manual](https://vt100.net/docs/vt510-rm/), 1st ed., 1993 | No | ignores an OSC string ([chapter 4](https://vt100.net/docs/vt510-rm/chapter4.html)) |
| xterm | patch 412, [xterm-411a](https://github.com/ThomasDickey/xterm-snapshots/tree/xterm-411a) | No | ignored |
| libghostty-vt | [83edd49](https://github.com/ghostty-org/ghostty/tree/83edd491e3024ae5e50393d62877b8897da1cccd) | No | ignored |
| Konsole | 26.11.70, [a24c3d71](https://invent.kde.org/utilities/konsole/-/tree/a24c3d71be3684f24d030aa2dbe9bd723d985233) | Yes | any color Qt can parse |
| ConEmu | build 230724, its [documentation](https://conemu.github.io/en/AnsiEscapeCodes.html) | No | not in its [ANSI escape codes](https://conemu.github.io/en/AnsiEscapeCodes.html) |

## Validation

### OSC34-1: The background is left alone

Input, one step per line:

```text
\e]34;red\a
\e]11;?\a
```

Expected screen:

```text
|___|
reply \e]11;rgb:ffff/ffff/ffff\a
```

### OSC34-2: Nothing on screen

Input, one step per line:

```text
A
\e]34;#0080ff\a
B
```

Expected screen:

```text
|AB_|
cursor 1,3
```

---

This is the Markdown version of <https://control-codes.page/osc/konsole-tab-color/>. On that page every validation case runs live in libghostty-vt, the terminal emulation core of Ghostty, compiled to WebAssembly.

The validation cases are written in the notation described in <https://control-codes.page/notation/index.html.md>.