claude-multi
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Tinkerer / early adopter · Any

Run Isolated Experiments Without Breaking Your Setup

The problem

You want to try a new model or plugin but you are worried about messing up your main Claude Code setup. One bad config edit and your daily driver is down.

The fix

Create a disposable instance with its own config directory. Experiment freely. If it breaks, delete it and start over -- your main setup is untouched.

The fear of breaking things

Your main Claude Code setup works. You have your MCP servers configured, your plugins installed, your CLAUDE.md tuned just right. The last thing you want is to install some experimental plugin or point at a new provider and watch the whole thing fall over.

claude-multi gives you a sandbox. Each instance gets its own config directory at ~/.claude-<name>/. Whatever you do in that directory stays there.

Setting up a sandbox

Terminal window
claude-multi

Pick Add new instance. Name it sandbox. Choose None / Custom as the template — you will configure it by hand, or pick a provider template if you want to test a specific model.

Say no to auto-sync and Nothing for copy options. This instance starts completely empty.

Terminal window
claude-sandbox

You now have a blank Claude Code session. Install that experimental plugin. Point at that weird endpoint. Edit settings.json however you want. If it catches fire:

Terminal window
claude-multi
# Pick: Remove instance
# Select: sandbox
# Delete config directory? y

Gone. Your main ~/.claude is untouched.

What to use a sandbox for

  • Testing new MCP servers before adding them to your main config
  • Trying a new provider without committing your API key to your primary setup
  • Experimenting with model parameters — change ANTHROPIC_MODEL in the sandbox’s settings.json and see what happens
  • Testing plugin combinations that might conflict
  • Reproducing a bug in a clean environment

Keeping some things shared

If you want the sandbox to have access to your existing plugins but nothing else, use the Select plugins copy option during creation:

Terminal window
claude-multi
# Add new instance
# Name: sandbox
# Copy options: Select plugins
# Pick the ones you want, skip the rest

This copies the selected plugins into the sandbox without symlinking. Changes in the sandbox do not affect your main setup.

Restoring from a broken state

If you break the sandbox but want to keep it:

Terminal window
claude-multi
# Pick: Instance details
# Select: sandbox
# Check what is wrong
# Edit ~/.claude-sandbox/settings.json to fix it

Or just remove it and recreate. The whole cycle takes under a minute.