Files tab

When you attach to a coding agent, the first tab is the harness. As soon as the agent edits a file inside a git repository under ~/workspace, a files tab for that repository appears next to it. You do not open it by hand.

The tab runs a diff viewer inside the repository folder. The viewer follows the agent's edits as they happen.

What the tab shows

The tab decides what to show each time it opens.

• If the working tree has uncommitted changes, it shows those changes.
• If the tree is clean and the agent made commits since the sandbox booted, it shows that range of commits.
• If there is nothing yet, it shows an empty diff and waits.

Edits outside ~/workspace do not create a tab. The harness is pointed at ~/workspace, so this covers normal work.

Switching tabs

Press ^p to open the command palette. Each open tab is listed as Tab: <name>. Pick one to switch. Press ctrl-x to detach from the whole session.

The diffViewer setting

The default viewer is lumen diff. Each environment can set its own with the diffViewer field.

version: v1
resource: environments
spec:
  id: starter
  imageId: starter
  enabledAiAgents:
    - id: claude_code
  sessionManager: shpool
  diffViewer: lumen diff

Apply the change.

helios code apply

The value is a command line. It runs inside the repository folder. When there is a commit range to show, the range is passed as the last argument and also set in the HELIOS_DIFF_RANGE environment variable. When the viewer is lumen diff, Helios adds --watch so the view updates live.

Requirements in the image

The viewer binary must exist in the sandbox image. At boot, Helios installs lumen if it is missing. If the download fails, or if you set a viewer that is not installed, the tab drops to a shell and prints why. Add the binary to your Dockerfile to be sure.

When the viewer exits, press Enter to reopen it. Press ctrl-c for a shell in the repository folder.