Panes overview

Every pane lives in the mosaic inside a room, has a stable UUID, appears in atrium pane list, and restores after quit/crash.

Pane types

Type

Summary

Reference

Terminal	xterm.js-backed PTY. Hosts shells and agents.	Terminal
Editor	Monaco code editor with LSP, git decorations, multi-file subtabs.	Editor
Markdown	Rich editor for Markdown with RTE/source toggle.	Markdown
Notepad	Workspace-scoped notebook — markdown, sketches, interactive canvas, sandboxed HTML.	Notepad
Browser	Full Chromium browser with DevTools, automation CLI, subtabs.	Browser
Source control	Git panel with staging, diffing, commits, branches, and the diff-review surface.	Source control
Search	Repo-wide text and regex search.	Search
Tasks	List and detail views for task cards.	Tasks
Diff review	Follow-along surface for an agent addressing a sent review batch.	Source control § Review
Viewers	Image viewer, diff viewer, snapshot viewer.	Viewers

The Library is a popover, not a pane — it materializes saved layouts and panes into the active workspace. See Library & vault.

What panes share

Every pane supports:

• Header with title, dirty indicator, and responsive overflow menu. Header actions collapse into an overflow ⋯ button as the pane narrows, and the title truncates on the left so the file basename or session ID stays readable. The default title is auto-generated from the pane type and content; override it with atrium pane rename <id> --name <name>. Copy Pane ID and Copy Session ID sit in the context menu for sharing or debugging.
• Split and subtab participation. Any pane can be dragged onto a split zone or another pane's header to join a subtab group. A + button in the header opens a new subtab on the same pane, and subtabs show a dirty indicator on unsaved state.
• Resize handles with snap and restore. Drag a divider as usual, or use the inline snap / restore controls that appear on hover to quickly collapse a pane to the edge or pop it back to the previous size.
• Focus cycling (Cmd+[ / Cmd+]) and click-to-focus.
• Close with confirmation if the pane has unsaved state or a running process. Closing a room with several saved Library panes prompts to save each one individually.
• Persistence — all pane-type-specific state is written to the workspace snapshot and restored on launch.
• CLI targetability — every pane appears in atrium pane list with its type, name, adapter (if any), workspace, and room.

Opening a pane

Panes are opened via any of:

• Keyboard shortcuts — Cmd+Shift+G (git), Cmd+Shift+F (search), Cmd+Shift+B (browser), Cmd+Shift+K (tasks list), Cmd+Shift+J (task detail), Cmd+Shift+L (Library popover).
• Launcher — Cmd+L in an empty terminal pane opens the adapter picker and pane-type launcher.
• File drop — drag a file from Finder to open an editor (or markdown editor, or image viewer) pane.
• CLI — atrium pane create --type <type> [--split <id>] [--cwd <path>] [--url <url>] [--focus].
• Other panes — the git changes pane opens a diff pane; a browser pane's new-tab action opens a browser subtab; the tasks list pane opens a task detail pane.

Closing

• Cmd+W closes the focused pane.
• The pane header menu has Close, Close others in split, and Move to new room/workspace.
• atrium pane close <id> from the CLI.

Pane navigator

The left sidebar's Rooms section shows every room in the active workspace with a color-coded miniature of its mosaic — split orientation and pane-type tints (notepad amber, diff-review teal, git red, browser blue, and so on) — so you can tell rooms apart at a glance. Click a room to switch; drag a room to reorder; right-click for rename / close / pin.

The sidebar's Summary view mode (toggled from the workspace section header) replaces the tree with per-workspace activity micro-cards — running agents, pending tasks, ahead/behind counts diffed against each worktree's fork base. Right-clicking any row offers the same actions as the tree view (open search, source control, edit, hide, remove). Use Copy Workspace ID from the same menu.

The Activity sidebar (Cmd+Shift+A) surfaces every running agent in the workspace, regardless of room, with jump-to-pane on click. See Activity sidebar.

Discovery from scripts and agents

Agents inside atrium can introspect the pane graph from the CLI. You can do the same from any shell with ATRIUM_CLI_PATH on your $PATH:

# Every pane, type, adapter, workspace, room
"$ATRIUM_CLI_PATH" pane list --json

# Just the agent panes
"$ATRIUM_CLI_PATH" agent list

# Just the browser panes
"$ATRIUM_CLI_PATH" browser list

Pane read and write are gated by MCP access scope — a per-pane setting (same-tab / same-workspace / all) that controls which other panes a given pane can see. Change a pane's scope from its header menu. The default is same-tab: an agent only sees panes in its own room. See Agent messaging for the scoping rules.