Runtimes

Runtimes determine where and how mux executes agent workspaces.

Runtime	Isolation	Best For
Local	All workspaces share the project directory	Quick edits to your working copy
Worktree	Each workspace gets its own directory	Running multiple agents in parallel
SSH	Remote execution over SSH	Security, performance, heavy parallelism

Choosing a Runtime

When creating a workspace, select the runtime from the dropdown in the workspace creation UI.

Init hooks can detect the runtime type via the MUX_RUNTIME environment variable:

This lets your init hook adapt behavior, e.g., skip worktree-specific setup when running in local mode.