> ## 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. # SSH Runtime > Run agents on remote hosts over SSH for security and performance Mux can run workspaces on a remote host over SSH. When configured, tool operations (file reads/edits, `bash`, etc.) execute on the remote machine. ## Threat model Mux treats the remote host as potentially hostile. By default it does **not** forward your local keys or credentials. The only data synced to the remote machine is: * a git archive of the project * [Project Secrets](/config/project-secrets) (explicitly configured) ## Why use SSH runtime * **Security**: Prompt injection risk is contained to the credentials/files on the remote machine. * SSH remotes pair well with [Agentic Git Identity](/config/agentic-git-identity). * **Performance**: Run many agents in parallel without burning laptop CPU/battery. ## Host value The host field accepts anything you can pass to `ssh `: * a hostname (for example `my-server.com`) * a username and hostname (for example `user@my-server.com`) * an alias from your `~/.ssh/config` (for example `my-server`) Mux delegates SSH configuration to your system `ssh` command, so advanced settings live in `~/.ssh/config`. Example entry: ```text theme={null} Host ovh-1 HostName 148.113.1.1 User root ``` ## Authentication Mux delegates to `ssh`. This is an abbreviated reference of common ways `ssh` authenticates. ### Local default keys `ssh` checks these locations by default: ```text theme={null} ~/.ssh/id_rsa ~/.ssh/id_ecdsa ~/.ssh/id_ecdsa_sk ~/.ssh/id_ed25519 ~/.ssh/id_ed25519_sk ``` ### SSH agent If you have an SSH agent running, add your key: ```bash theme={null} ssh-add ~/.ssh/my_key_ecdsa ``` ### `~/.ssh/config` You can also set an explicit identity file: ```text theme={null} Host my-server HostName 148.113.1.1 User root IdentityFile ~/.ssh/id_rsa ``` ## Coder Workspaces If you use [Coder](https://coder.com), see the [Coder runtime](/runtime/coder) page.