tmux bell-action configuration for non-intrusive activity alerts

Answer first

No. visual-activity does not override bell-action. They are separate monitoring classes in tmux: bell-action reacts to the ASCII BEL character and visual-activity reacts to pane output/activity after a period of silence. Enabling both can produce independent notifications rather than one superseding the other.

A consistent non-intrusive visual alert setup relies on tmux-side bell handling plus disabling the terminal emulator’s audible bell. The exact options available are version-sensitive, so verify your build before applying.

Confirmed facts

• bell-action controls what tmux does when a BEL is received in a pane. Valid values include any, current, other and none.
• monitor-bell enables tmux to monitor bells in panes. It is a prerequisite for bell-action to have effect.
• visual-activity monitors activity, not BEL. It will not silence a BEL and will not replace bell-action.
• Option names and defaults are build-dependent. Check the running build with tmux show-options -g and tmux show-options -gw before assuming bell-action or visual-bell exists.

Likely configuration for visual-only alerts

The following is a commonly used starting point for tmux 3.x. Treat it as likely, not guaranteed, until verified in your environment.

1. Enable bell monitoring globally:

   tmux set-option -g monitor-bell on

2. Choose bell scope. Session-wide visual cue:

   tmux set-option -g bell-action any

   Use current for only the active window or other for background windows if you want narrower scope.
3. If your build provides visual-bell, enable it for a status-line flash instead of an audible bell:

   tmux set-option -g visual-bell on

   If visual-bell is not listed by show-options, this step cannot be applied.
4. Disable audible bell in the terminal emulator itself. tmux cannot guarantee suppression of the emulator’s own bell handling, especially over SSH where forwarding behavior varies.
5. Keep visual-activity separate. It can be enabled for activity alerts, but it does not affect BEL handling:

   tmux set-option -g visual-activity on

Verification steps

• Capture current options:

  tmux -V
  tmux show-options -g | grep -Ei 'bell|visual|monitor'
  tmux show-options -gw | grep -Ei 'bell|visual|monitor'

• Trigger a BEL in a test pane:

  printf '\a'

  Observe status-line message/flash versus audible beep in your local terminal and over SSH.
• Change one option at a time and repeat the BEL test to confirm visual alert without system bell in your environment.

Uncertainty note: over SSH, tmux status-line alerts are generally more consistent than system bells because they travel inside the session, but local terminal emulator settings and SSH bell forwarding can still add beeps or suppress alerts. No tmux-only setting guarantees identical behavior everywhere.

To tailor the recommendation, please confirm whether visual-bell appears in your tmux show-options -g output. Its presence changes whether a tmux-side visual flash is available or you must rely solely on bell-action plus terminal settings.