Tmux Orchestrator

Overview

This skill enables orchestration of tmux sessions through programmatic tmux commands via the Bash tool. It provides patterns for creating multi-window, multi-pane development environments suitable for complex projects requiring simultaneous work on multiple components.

The user has a custom tmux configuration with non-standard keybindings. Reference references/keybindings.md for the full configuration details.

Core Concepts

Session Structure

A tmux session consists of:

• Session: Top-level container (e.g., "project-dev")
• Windows: Tabs within a session (e.g., "backend", "frontend", "logs")
• Panes: Split sections within a window (side-by-side or stacked)

Pane Naming Convention

Panes are numbered starting from 1 (due to user's base-index configuration):

• session:window.1 - First pane in window
• session:window.2 - Second pane in window
• And so on

Split Types

Important: tmux split naming can be counterintuitive:

• -h (horizontal split) creates a vertical divider resulting in side-by-side panes
• -v (vertical split) creates a horizontal divider resulting in stacked panes

Creating Sessions via Bash Tool

Basic Pattern

# Check if session exists
tmux has-session -t session-name 2>/dev/null

# Create new session with first window
tmux new-session -d -s session-name -n window-name -c /path/to/dir

# Split panes
tmux split-window -h -t session-name:window-name -c /path/to/dir  # Side-by-side
tmux split-window -v -t session-name:window-name -c /path/to/dir  # Stacked

# Create additional windows
tmux new-window -t session-name -n second-window -c /path/to/other-dir

# Send commands to specific panes
tmux send-keys -t session-name:window-name.1 "command here" C-m

# Select default window
tmux select-window -t session-name:first-window

# Attach (use os.execvp in scripts, or direct command in bash)
tmux attach-session -t session-name

Example: Two-Component Project

# Create session with backend window
tmux new-session -d -s myproject -n backend -c /path/to/backend
tmux split-window -h -t myproject:backend -c /path/to/backend

# Create frontend window
tmux new-window -t myproject -n frontend -c /path/to/frontend
tmux split-window -h -t myproject:frontend -c /path/to/frontend

# Optional: Send startup commands
tmux send-keys -t myproject:backend.1 "npm run dev" C-m
tmux send-keys -t myproject:frontend.1 "npm start" C-m

# Select backend window by default
tmux select-window -t myproject:backend

# Attach
tmux attach-session -t myproject

Common Patterns

Pattern 1: Editor + Terminal Layout

Single window with editor on left, terminal on right:

tmux new-session -d -s dev -n main -c /path/to/project
tmux split-window -h -t dev:main -c /path/to/project
tmux send-keys -t dev:main.1 "nvim" C-m
tmux attach-session -t dev

Pattern 2: Multi-Service Development

Multiple windows, one per service:

SESSION="services"

# API service
tmux new-session -d -s "$SESSION" -n api -c /path/to/api
tmux split-window -h -t "$SESSION:api" -c /path/to/api
tmux send-keys -t "$SESSION:api.1" "go run main.go" C-m
tmux send-keys -t "$SESSION:api.2" "go test -v ./..." C-m

# Frontend service
tmux new-window -t "$SESSION" -n frontend -c /path/to/frontend
tmux send-keys -t "$SESSION:frontend" "npm run dev" C-m

# Database/logs
tmux new-window -t "$SESSION" -n infra -c /path/to/project
tmux send-keys -t "$SESSION:infra" "docker compose up" C-m

tmux select-window -t "$SESSION:api"
tmux attach-session -t "$SESSION"

Pattern 3: Three-Pane Development

Editor + two terminals in same window:

tmux new-session -d -s dev -n main -c /path/to/project
tmux send-keys -t dev:main "nvim" C-m

# Split right
tmux split-window -h -t dev:main -c /path/to/project

# Split bottom right
tmux split-window -v -t dev:main -c /path/to/project

# Result: Editor on left, two terminals stacked on right
tmux attach-session -t dev

Using Existing Tools

The user has shell aliases and scripts for tmux management. Leverage these when appropriate:

Shell Aliases

• tma session-name - Attach to session
• tmn session-name - Create new session
• tml - List sessions
• tmk session-name - Kill session
• tms - Interactive session manager (fzf-based)
• tmd - Create 3-pane dev session automatically

When to Use Existing Tools vs Custom Sessions

• Use tmd for simple single-project development (creates nvim + 2 terminals)
• Use custom tmux commands for multi-component projects requiring specific layouts
• Use tms to list/switch between sessions interactively

Session Management

Check Session Exists

if tmux has-session -t session-name 2>/dev/null; then
    echo "Session exists"
    tmux attach-session -t session-name
else
    # Create session
fi

List Running Sessions

tmux list-sessions
# Or use alias
tml

Kill Session

tmux kill-session -t session-name
# Or use alias
tmk session-name

Sending Commands to Panes

Basic Command

tmux send-keys -t session:window.pane "command" C-m

The C-m sends a carriage return (Enter key).

Examples

# Send to first pane of backend window
tmux send-keys -t myproject:backend.1 "npm run dev" C-m

# Send to specific pane without executing (no C-m)
tmux send-keys -t myproject:frontend.2 "docker compose up -d"

# Send multiple commands
tmux send-keys -t myproject:backend.1 "cd src" C-m
tmux send-keys -t myproject:backend.1 "npm install" C-m
tmux send-keys -t myproject:backend.1 "npm run dev" C-m

Working Directory Handling

All panes default to opening in the specified directory (-c flag). The user's tmux config is set to preserve the current path when creating new panes/windows.

# Window opens in /path/to/backend
tmux new-window -t session -n backend -c /path/to/backend

# This pane also opens in /path/to/backend (inherits from window)
tmux split-window -h -t session:backend -c /path/to/backend

# Override path for specific pane
tmux split-window -h -t session:backend -c /path/to/different/dir

Session Persistence

The user has tmux-resurrect and tmux-continuum plugins:

• Sessions auto-save every 15 minutes
• Sessions survive system restarts
• No need to recreate sessions manually after reboot

Once a session is created, it will persist across reboots via the continuum plugin.

Navigation Reference

Users navigate tmux with these keybindings (from references/keybindings.md):

• Switch windows: Shift + Left/Right (no prefix)
• Switch panes: Alt + Arrow Keys (no prefix)
• Prefix key: Ctrl+a (not the default Ctrl+b)

Template Script

See scripts/session-template.sh for a complete example bash script demonstrating session creation patterns. This script can be adapted for specific projects.

Best Practices

1. Check for existing sessions before creating to avoid duplicates
2. Use descriptive window names that indicate purpose (backend, frontend, logs, etc.)
3. Send commands after pane creation, not during creation, for reliability
4. Select a default window before attaching to control which window appears first
5. Use full paths for working directories (no ~ expansion needed)
6. Preserve session names across recreations for consistency with resurrect/continuum
7. Leverage existing tools (tms, tmd) when they fit the use case

Resources

scripts/session-template.sh

Generic bash script template demonstrating how to create multi-window, multi-pane sessions. Shows:

• Session existence checking
• Window creation
• Pane splitting
• Command sending
• Session attachment

Adapt this template for project-specific session creation scripts.

references/keybindings.md

Complete reference of the user's custom tmux configuration including:

• Custom prefix key (Ctrl+a)
• Pane navigation (Alt + arrows)
• Window switching (Shift + arrows)
• All split, resize, and management keybindings
• Available shell aliases
• Plugin information (resurrect, continuum, etc.)

Load this reference when users ask about navigation or keybindings, or when debugging tmux behavior.