split-editor

Edit pi prompts in a live tmux split without blocking pi's TUI.

split-editor replaces pi's blocking Ctrl+G external-editor workflow. Press Ctrl+G in pi's prompt editor to open the current prompt in your editor (nvim by default) in a tmux split. When the editor exits, the edited text is read back into pi's prompt.

Pi stays visible and resize-aware in the original pane while the split is open. The prompt is locked during editing so it cannot be mutated in two places at once.

Demo

https://github.com/user-attachments/assets/47a81b03-8292-45b9-8c85-508719c5f585

Requirements

• pi
• tmux
• nvim by default; set the editor option to use a different terminal editor (see Configuration)

Installation

From npm:

pi install npm:split-editor

From a local checkout:

pi install /path/to/split-editor

For development:

pi -e .

Usage

1. Start pi inside tmux with this package loaded.
2. Type a prompt.
3. Press Ctrl+G.
4. Edit in the tmux split.
5. Save and quit the editor.
6. The edited text replaces the pi prompt.

Pressing Ctrl+G again while the split editor is already open will not open a second editor.

Configuration

Configuration is read each time Ctrl+G opens the split editor, so file/env changes are picked up without reloading the extension.

Options:

Option	Env var	Default	Description
editor	SPLIT_EDITOR_EDITOR	nvim	Editor command to run in the tmux pane.
size	SPLIT_EDITOR_SIZE	50%	tmux split size passed to tmux split-window -l.
direction	SPLIT_EDITOR_DIRECTION	h	h/horizontal for side-by-side, v/vertical for top/bottom.
showIndicator	SPLIT_EDITOR_SHOW_INDICATOR	true	Show SPLIT EDITOR OPEN in the editor border while locked.

Precedence, lowest to highest:

1. Defaults
2. Global config: ~/.pi/agent/extensions/split-editor.json
3. Global pi settings: ~/.pi/agent/settings.json under splitEditor
4. Project config: .pi/split-editor.json
5. Project pi settings: .pi/settings.json under splitEditor
6. Environment variables

Standalone config files use the options directly:

{
  "editor": "nvim",
  "size": "50%",
  "direction": "horizontal",
  "showIndicator": true
}

Pi settings.json uses a splitEditor object:

{
  "splitEditor": {
    "editor": "nvim",
    "size": "50%",
    "direction": "vertical",
    "showIndicator": false
  }
}

Environment example:

SPLIT_EDITOR_EDITOR="nvim" \
SPLIT_EDITOR_SIZE=50% \
SPLIT_EDITOR_DIRECTION=h \
SPLIT_EDITOR_SHOW_INDICATOR=false \
pi

SPLIT_EDITOR_SHOW_INDICATOR accepts 1, true, yes, on, 0, false, no, or off.

Notes and limitations

• Requires tmux for live split behavior; falls back to pi's default external editor outside tmux.
• The pi prompt editor ignores input while the split editor is open.
• If the editor exits non-zero, the temp file is still read back into pi and a warning is shown.
• Temporary files are removed on a best-effort basis after the editor closes.