claudeX — Claude Code eXtended

This is Dr. Ralf S. Engelschall (RSE)'s opinionated Claude Code environment for macOS and Linux. It mainly provides a thin claudex (claude eXtended) wrapper command which provides the following distinct features on top of the regular Claude Code command:

• Adjusted Theme: It uses the companion tool ansi-recolor, also from RSE, to on-the-fly re-color Claude Code's terminal UI (configured to run in regular light theme) into the RSE brown/blue color theme, without having to patch Claude Code (with tools like TweakCC, which regularly have to be updated to not fail on this task).

  Rationale: RSE is obsessed from "distraction free coding", which, for him, implies that everthing has to use his unobtrusive brown/blue color theme.

• Terminal Multiplexing: It uses the companion tool tmux to run Claude Code and its companion tools in an opinionated virtual terminal environment, with multiple screens and multiple panes on each screen.

  Rationale: Allow one to easily run multiple Claude Code sessions in parallel with full terminal interaction.

• Encapsulated Runtime: It optionally uses the companion tool capsula, also from RSE, for executing claude inside a cleverly established Docker container, which mimicks the host environment (filesystem layout, user/group name/id, etc) as close as possible.

  Rationale: Prevents any programs claude spawns from damaging more than the current working directory.

• Companion Tools: It allows you to execute (visually in a modal window on top of Claude Code with the help of tmux popups) the companion tools LazyGit (for Git version control) and Bash (for Shell).

  Rationale: The most important companion tool is LazyGit, allowing the easily partial backout of changes Claude Code made to source code.

Impressions

The following is a main view of the macOS Terminal with a claudeX session running. Three Claude Code instances are running in separate panes of the screen.

This is with LazyGit opened on top of Claude Code in a modal window:

Installation

# initially
$ npm install -h @rse/claudex
$ claudex [-C/--capsula] install

# regularly
$ claudex [-C/--capsula] update

Usage

$ claudex
    [-C|--capsula]         # execute Claude Code inside a Capsula sandbox container")
    [-T|--tmux [session]]  # wrap Claude Code in a Tmux terminal multiplexing session (optional session name)")
    [-R|--recolor]         # wrap Claude Code with ANSI recoloing for improved theming")
    [-A|--ase]             # enable ASE-specific Claude Code statusline and ASE_* environment variables")
    [...options...]        # arbitrary Claude Code options

See Also

• Claude Code
• Capsula
• Tmux
• ANSI Recolor
• Agentic Software Engineering (ASE)

License

Copyright © 2026 Dr. Ralf S. Engelschall Licensed under GPL 3.0