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ProjectslassoDocs

Getting started

lasso is a single binary. It runs on the machine where your coding agents live, drives that machine's herdr session, and serves a web UI on loopback. This page takes you from nothing to a working UI on http://127.0.0.1:8090.

Requirements#

  • Linux or macOS, on amd64 or arm64. The Mac app is a separate download, and talks to a lasso on any of them.
  • herdr, the terminal multiplexer lasso is a UI over. The installer below installs it for you if it is missing.
  • ttyd on PATH. lasso serves its terminals by spawning ttyd processes, and nothing installs it for you: use your package manager (apt install ttyd, brew install ttyd, or your distro's equivalent).
  • ssh and an ~/.ssh/config, only if you want lasso to drive other machines too. Those machines need a running herdr of the same protocol, git, and the sqlite3 CLI, but not lasso itself. See What a remote host needs.
  • Chrome or Chromium, only for the shared browser. Everything else works without it.

Install#

curl -fsSL https://executionassociates.com/install-lasso | sh

The script downloads the latest release binary for your platform from GitHub, verifies it against the release's checksums.txt, and installs it as ~/.local/bin/lasso. It then installs herdr (from https://herdr.dev/install.sh) if herdr is not already on your PATH.

At a terminal, the script asks whether lasso may send anonymous usage analytics: which views and features get used and rough counts, under a random id. Usage analytics lists exactly what is sent. You can change your answer any time with lasso telemetry on|off or in Settings › General › Anonymous usage analytics.

Variable Effect
LASSO_INSTALL_DIR Install somewhere other than ~/.local/bin.
LASSO_SKIP_HERDR=1 Don't install herdr; just print the command to install it yourself.
LASSO_TELEMETRY=0 Turn off lasso's anonymous usage analytics without being asked. Passing --no-telemetry (… | sh -s -- --no-telemetry) does the same. 
curl -fsSL https://executionassociates.com/install-lasso | LASSO_INSTALL_DIR=/usr/local/bin sh

If the install directory is not on your PATH, the script says so and prints the export PATH=... line to add.

Start it#

lasso start

lasso start (alias lasso up) runs the server in the background, writes its PID to ~/.lasso/lasso.pid and its log to ~/.lasso/lasso.log, and prints the URL once it has bound:

lasso started (pid 41234) → http://127.0.0.1:8090

The other lifecycle commands:

Command What it does
lasso status Whether the background server is running, and its URL.
lasso stop (alias down) Stop the background server.
lasso restart Stop it if running, then start it.
lasso serve Run in the foreground instead. A bare lasso does the same.

start, restart and serve accept the server flags, for example lasso start -listen 127.0.0.1:9000. lasso serve -h lists them, and Configuration describes each one. To keep lasso running across reboots, run it as a systemd unit: see Running under systemd.

Open the UI#

Open http://127.0.0.1:8090 in a browser on the same machine. You get herdr's terminal in the main column, a sidebar of tabs on the right (Files, Browser, Terminal, Usage, Settings and others), and a footer with New, the host menu (server icon), the sidebar toggle and your agents' usage budgets. The web UI walks through the layout.

lasso binds to loopback by default, and that is deliberate: the terminal is a writable shell as you, and the MCP endpoints can spawn agents. To reach it from your other devices, serve it on your tailnet with -tailnet, or publish it through Cloudflare Access with -listen-access. Both serve HTTPS, which a phone needs, and both check who is calling before lasso answers. See Deployment and On your phone.

Check the install#

lasso doctor

lasso doctor prints one line per check and exits non-zero if a hard requirement fails: herdr missing from PATH, or ~/.lasso not writable. It also warns when the herdr server is unreachable or speaks a different protocol, when herdr's agent integrations are missing, when another process holds port 8090, when the binary's directory is not on PATH, and when a newer release exists. CLI reference lists every check.

doctor does not check for ttyd. If the UI loads but the terminal stays blank, check that ttyd is installed and look in lasso's log (~/.lasso/lasso.log for lasso start, journalctl --user -u lasso under systemd).

herdr version#

This lasso release targets herdr protocol 22, the protocol herdr has spoken since v0.9.0, and is tested against herdr v0.9.2. lasso talks to herdr over its unix socket (~/.config/herdr/herdr.sock, or $HERDR_SOCKET_PATH), so the protocol is what has to match:

  • lasso doctor warns when the local herdr speaks a different protocol.
  • Another machine is only selectable in the host menu when its herdr speaks the same protocol as the herdr on lasso's own machine. The menu offers to update or set up herdr on a host that is behind. See Hosts.

Upgrade herdr on lasso's machine and on your other hosts together. Upgrading a herdr server across a protocol change can end the processes running in its panes, so checkpoint active agents before you approve a herdr restart. Updating covers both lasso and herdr updates.

Running lasso inside herdr#

lasso's main terminal runs herdr. If you start lasso from a shell that is itself inside a herdr pane, herdr refuses to launch nested by default and the terminal won't come up. Allow it in ~/.config/herdr/config.toml:

[experimental]
allow_nested = true

Starting lasso from outside herdr (a plain shell, systemd, lasso start from an ssh session) needs nothing.

Next steps#