> ## Documentation Index
> Fetch the complete documentation index at: https://mux.coder.com/llms.txt
> Use this file to discover all available pages before exploring further.

# .muxignore

> Sync gitignored files to worktree workspaces

Git worktrees share the `.git` directory but **not** untracked or gitignored files. This means files like `.env` that are in your `.gitignore` won't be available in worktree-based workspaces.

A `.muxignore` file lets you declare which gitignored files should be copied into new worktree workspaces.

## Setup

Create a `.muxignore` file in your project root (alongside `.gitignore`):

```gitignore theme={null}
# Sync these gitignored files to worktree workspaces
!.env
!.env.local
!config/secrets.json
```

Only lines prefixed with `!` (negation) are actionable — they identify gitignored files to copy. Comments (`#`) and blank lines are ignored.

> Mux only copies files that are already gitignored in your project and currently exist on disk.

## Behavior

* **When:** Files are copied after the git worktree is created, before [init hooks](/hooks/init) run — so your init scripts have access to `.env` and other secrets.
* **Source:** Your project root directory (the main checkout).
* **Copy mode:** Physical file copy, not symlink. Each workspace gets its own independent copy.
* **No overwrite:** Files that already exist in the worktree are not overwritten.
* **Best-effort:** If a file can't be copied, Mux logs debug information and continues — it won't block workspace creation.

## Where to place it

Place `.muxignore` in the project root, next to your `.gitignore`. You may want to commit it to your repo so all collaborators share the same sync rules.