Feature request: configurable tmux teammate pane layout for Agent Teams

Summary

In Agent Teams split-pane mode under tmux, teammate panes are currently stacked vertically beside the lead pane. With 4-5 teammates, each teammate pane becomes very short, making logs and code output hard to read.

Current behavior

A common layout looks like this:

+-----------+----------------+
| lead pane | teammate 1     |
|           +----------------+
|           | teammate 2     |
|           +----------------+
|           | teammate 3     |
|           +----------------+
|           | teammate 4     |
|           +----------------+
|           | teammate 5     |
+-----------+----------------+

The lead pane is useful as the main control pane, but the teammate panes become compressed vertically.

Requested behavior

Please consider adding a way to configure or improve the tmux pane layout for Agent Teams while keeping the lead pane fixed. For example:

+-----------+----------------+----------------+
| lead pane | teammate 1     | teammate 2     |
|           +----------------+----------------+
|           | teammate 3     | teammate 4     |
|           +----------------+----------------+
|           | teammate 5     |                |
+-----------+----------------+----------------+

Possible options:

• Keep the lead pane full-height on the left.
• Arrange teammate panes in a grid on the right.
• Use simple rules such as 4 teammates = 2x2, 5 teammates = top 2 / bottom 3, 6 teammates = 3x2.
• Optionally expose a tmux layout setting or hook so users can provide their own layout command.

Motivation

Agent Teams encourages running multiple teammates at once, but the current vertical stacking makes it difficult to monitor more than 2-3 teammates in tmux. A configurable or smarter layout would make split-pane mode much more usable on wide monitors without disrupting the lead pane workflow.

Environment

Observed in tmux split-pane mode. The request is not about mouse resizing; it is about structural pane arrangement for teammate panes.