Share a session

Someone wants to watch Claude Code work, or help you in a shell. The session-share package lets them join one of the workspace’s tmux sessions, in a browser or over SSH, read only or typing along. When the time you chose runs out, they are disconnected and your session keeps running.

You need: a workspace, and a tmux session in it. Every devmachine ssh login already gives you one.

Before you start: machine, skills, workspace

curl -fsSL https://mydevmachine.sh/install.sh | sh
devmachine setup
devmachine skills add
devmachine workspaces new acme
devmachine sync

Already have a machine? Skip setup. Already have the workspace? Skip the last two.

From the app

With the session-share package on the workspace (step 1 below), right-click the session in the sidebar and choose Share…. Pick how long, and whether they only watch or can type. The first share of a workspace publishes its share server at share-<workspace>.<your domain>, so the link works for anyone. Copy the link and the password: the password shows only there.

While it is shared, the session has a mark beside its name. Right-click it for Open chat, Add 30 minutes and Stop sharing. The chat opens in the context panel: guests write from the shared page, you answer there. Settings → Shares lists every share this Mac started.

By hand

1. Add the package

devmachine packages pin
devmachine packages add session-share --workspace acme
devmachine sync

packages pin moves you to the packages release that has session-share.

2. Find the session

devmachine run --argv --workspace acme -- tmux ls

The session devmachine ssh acme opens is called main.

3. Share it

devmachine run --package session-share --workspace acme -- start main --mode read --for 1h

Sharing "main" (read only) until 16:40.

  Link:      http://127.0.0.1:7690/s/k3j2abcdwxyz/
             Only this machine can open it. Publish it with: session-share expose
  Password:  v3bd-28s5-nave-dvcg
             Send it apart from the link.
  Stop:      session-share stop k3j2abcdwxyz

Always pass --workspace. The share runs as the workspace’s account, which owns its tmux sessions; without it the command would run as root.

--mode write lets them type too. --for takes anything from 1m to 24h.

4. Give the link a public address

The link above only works on the machine. Publish the share server once, at a name of your own:

devmachine expose add acme 7690 --host share.example.com
devmachine run --package session-share --workspace acme -- expose proxy --url https://share.example.com

From then on every share’s link starts with https://share.example.com. A machine with no public address can use Tailscale Funnel instead, at a ts.net name: -- expose funnel.

Send the link and the password through different channels. They open the link, type the password and see the session.

5. Or let them in over SSH

devmachine run --package session-share --workspace acme -- start main --ssh-github bob --no-web --for 1h

Their GitHub keys can log in to the workspace’s account for that hour, and land straight in the shared session: no shell, no tunnels, no other command. They connect with ssh -t to the account and the machine’s address.

6. Talk to them

The shared page has a chat beside the session. Up to five people can be there at once; --max-viewers changes it. Answer from your terminal:

devmachine run --package session-share --workspace acme -- chat k3j2abcdwxyz --message "I'll push the fix now"
devmachine run --package session-share --workspace acme -- chat k3j2abcdwxyz --follow

The chat is text only. Nothing written there reaches the session.

7. Stop, or give them more time

devmachine run --package session-share --workspace acme -- list
devmachine run --package session-share --workspace acme -- extend k3j2abcdwxyz --for 30m
devmachine run --package session-share --workspace acme -- stop k3j2abcdwxyz

stop disconnects them within a second.

What they can do

	read	write
See the shared session, live	yes	yes
See your other sessions	no	no
Run a tmux command: kill the session, open a window, detach you	no	no
Type into the program in the session	no	yes

Write means trust. Someone who can type into a shell, or approve a tool in Claude Code, runs commands as the workspace’s account. Keep write shares short, and for people you would hand your keyboard to.

With your agent

Share the main tmux session of my devmachine workspace acme with bob for
an hour, read only.

The agent adds the package if it is missing, runs start, and hands you the link and the password to pass on.

Check it: open the link in a private window, sign in, and watch your session move as you type in it. -- list shows one viewer.

Source: session-share, tmux