Option to show tab numbers alongside custom tab titles in the tab bar

[zya]

Idea

A config option (e.g. [ui] show_tab_numbers = true) that renders the tab's number next to its title in the tab bar, e.g. 2 · Research, including for renamed tabs.

Current behavior

Auto-named tabs display their number as the label, but once a tab is renamed the number is no longer visible anywhere in the tab bar.

Why

Indexed tab switching (switch_tab = "ctrl+alt+1..9" and similar) is much more useful when the target number is visible at a glance. Today you either keep auto-named tabs (numbers but no titles) or named tabs (titles but no numbers).

Workaround today

A small plugin subscribed to tab.created/closed/moved/renamed that rewrites labels to N · title via herdr tab rename. Works, but it mutates user-visible labels and fights manual renames — a display-layer toggle would be cleaner.

(Originally filed as #1380, closed as feature requests belong here.)

[baklim]

It's also would be nice for workspaces.

[pfitz]

Hitting this too, plus a knock-on effect I don't see mentioned in the thread.

herdr 0.8.0, one workspace, six tabs, five renamed to whatever the agent inside is working on. switch_tab sits on prefix+1..9, so the numbers matter — but tab_chrome_label (src/ui/tabs.rs:36-39) uses the position only as the fallback label:

ws.tab_display_name(tab_idx).unwrap_or_else(|| (tab_idx + 1).to_string())

Renaming doesn't hide the number so much as consume it. Six tabs in, prefix+3 is guesswork.

The knock-on: the sidebar's tab token renders that same display name, so the number is missing from the expanded Agents sidebar as well. A single ui.show_tab_numbers would fix both surfaces — worth noting, since the thread reads as tab-bar-only.

One workaround I considered and rejected: baking the number into the name (3 · health checks). It goes stale the moment a tab is closed or moved, and it fights the auto-naming rules.

[cspipaon]

+1 for this feature

[bkemmer]

+1 for this too.

And I keep trying to reach for the first one with 0 since it's tmux's default.

[ChrisMuga]

+1 for me as well; 🙏🏿

[Matra-Master]

https://github.com/Angel-O/herdr-tab-numbers https://github.com/Angel-O/herdr-labels
This person made a plugin with something similar to what we want. I'm about to test it myself but wanted to point all of you to something we can use for now and then maintainers use as inspiration in a PR. Hope this helps!
Edit: I missed that the repo was read-only because it's creator made another better plugin!

[alhafoudh]

Another data point on where this should read the number from, since the thread has two candidate sources.

The socket API already carries both, separately, which supports this being display-only. herdr tab list on 0.9.0:

w26  tab_id=w26:t2  number=2  label=dotfiles
w2A  tab_id=w2A:t1  number=1  label=1
w2A  tab_id=w2A:t2  number=2  label=2
w2B  tab_id=w2B:t2  number=2  label=1

But number is not the value to render. w26 and w2B each hold exactly one tab, and in both that tab's number is 2: it does not reset after an earlier tab closes. w2B is the clearest case, its generated label is 1 while its number is 2, so the two disagree on a tab nobody has renamed. switch_tab selects by position, so a label built from number would print a key that does not work. Same point #3958 made before it was closed.

So show_tab_numbers, or {index} in the tab_format from #3299, wants the positional index, the value tab_chrome_label already falls back to in @pfitz's snippet above, not public_tab_number.

Still absent in 0.9.0: the v0.9.0 config reference has no tab label key at all. prompt_new_tab_name, hide_tab_bar_when_single_tab, tab_bar_position, tab_bar_right, tab_bar_right_separator, and nothing for the label itself.

Environment: herdr 0.9.0, macOS, stable channel.