Basics

Sessions

A session is one agent working on one task in a project. Sessions run side by side, in every project, and each says when it needs you.

The sidebar

The sidebar lists your projects (the switch at its top shows Machines instead; Add project at its bottom opens a folder), the one you last worked in first (sent a message or started a session in), each with its open sessions, the one you last worked in first, then its newest past ones (More shows older ones). Click a project's name to fold or unfold it. Hover it for New session and ⋯ (also on right-click), which has New worktree…, Open terminal, Move to section, Copy path, Archive and Remove from sidebar.

Sections group projects under a name, below the projects in none. Drag a project by its name onto a section (its name or any project in it) to put it there, onto a project in no section to take it out, or onto Archived to archive it. A project's Move to section does the same, New section… included (also right-click the sidebar where there's no row, or ⌘P, New section…). Click a section's name to fold it; folded, it shows what in it needs you. Drag a section's name onto another to take its place, or use its ⋯ (also on right-click) for Rename…, Move up, Move down and Remove section, which leaves its projects in none.

Archive puts a project away in Archived, at the bottom of the sidebar (also ⌘P, Archive …). Its sessions stop, as with Remove from sidebar, but it keeps the ones you had open: click it in Archived to bring it back with them, or right-click it for Unarchive.

To keep a session on top of the sidebar, whatever its project, right-click it and choose Pin to top, or press ⌘P and choose Pin session to top. A pin marks it while it's idle. Unpin takes it back to its project.

A session's own subagents show under it, on a dotted line down from its mark: a spinner while one runs, with what it's doing now; a check once it's done; red if it failed; a grey ring if it was stopped. Click one to see it in its session. They're the ones since your last message; past five, those that finished fold into one line (click it to show them). Only Claude Code's show so far. With Balanced on, a lead's workers sit under it the same way. One whose session is open here has its own subagents under it; one that isn't (the worker on the lead's own machine runs without one) opens with a click. In Machines, workers stay with their machine.

The mark before a session says how it is:

A folded project shows its most pressing mark. The Board gathers what needs you from every project and machine.

Starting a session

⌘N, the New session button at the top of the sidebar, or New session on a project starts a session; an untouched new one is reused. It runs on the project's agent with Settings' defaults (Agents and models).

Switching between sessions

Besides clicking one in the sidebar:

Finding in a session

⌘F opens a find bar over the session. Type, and the newest message holding it is lit and shown, with how many there are ("2 of 5"). ↩, ⌘G or ↑ goes to the next older one, ⇧↩ or ↓ the next newer, round the ends; Esc or ✕ closes it. It looks in what you and the agent said, notices and cards, not in tools' output.

Allowing from the keyboard

When the agent asks to use a tool, the request sits on top of the message box with Deny, Always allow (when it can be remembered; its tooltip says where) and Allow. ⌘↩ allows the oldest waiting request and ⌘⌫ denies it; "1 of 3" says more are waiting. The tool's card in the conversation has the same buttons and the diff. Questions and plans are answered in their own cards.

Permission modes

The mode picker under the message box sets how much the agent does without asking you. ⇧Tab steps through the first three:

Bypass permissions and Full access let the agent edit files and run commands without asking: you confirm once per session, and the picker turns red. Claude Code restarts the session on the same conversation to take Bypass permissions, so not while Claude works.

New sessions start in Manual (Claude Code), Auto (Codex) or Ask (Pi), unless the agent's page in Settings gives another.

Stopping a turn

Esc or ⌘. stops the turn, as does Stop at the right of the message box; Esc first closes an open list in the message box. Claude Code still runs messages you queued; Pi gives its queued messages back.

Rewinding to an earlier message

Hover a message you sent and click Rewind (or right-click it: Rewind…). Choose what goes back to before that message: the conversation (your message returns to the message box), the files the agent changed since, or both. Rewind works for Claude Code and Pi, not Codex, and not while the agent works.

Closing and reopening

⌘W, or ✕ on the session showing in the sidebar, closes it: its agent stops, and the conversation stays among the project's past sessions. While it works or waits for you, Magnum asks first. ⇧⌘T reopens the session closed last; again, the one before. A past session reopens with a click and goes on when you send it a message.

Quitting Magnum doesn't stop a session that has started working: it keeps going, and Magnum picks it up when it opens again.

Titles and the session menu

A session is named by the first line of your first message, until Claude Code or Pi titles it after its first turn. Codex sessions keep their first message.

Click the title in the toolbar (with tabs, right-click the session's tab), or right-click a session in the sidebar, for its menu: Detach (or Dock), Continue on another copy of the project (Environments), Copy session ID and Close. Pi's sessions add their own, among them Session tree, Fork from a message… and Rename session…

Tabs and tiles

The sessions you open in the window line up as tabs in the toolbar, on the line with Run and the panes' buttons, from any project (another project's name shows beside its title), with the projects' terminals. Click a tab to show it. Point at a tab for its two buttons: Detach on the left, and ✕ on the right, which takes it off the strip (the session stays open in the sidebar; a terminal ends).

Detach (on a tab, the button at the right under the message box, the session menu, or ⌘P) turns every tab into a tile, side by side, then in rows, that session with the keyboard; the strip goes. From then on each session you open (from the sidebar, ⌘N or the Board) joins the tiles. When there's no room for another, the tile you used least recently gives way; it stays open in the sidebar. Under a tile's message box, the environment and the pickers show their icons alone; point at one for its name.

Dock (the arrow in a tile's header, the session menu, or ⌘P) turns every tile back into a tab, that session in front. The ✕ in a tile's header (or ⌘W in it) closes the tile: the session stays a tab, and nothing stops; closing the last tile docks it.

⌃⌥T switches between tabs and tiles. In tiles, ⌃⌥←, ⌃⌥→, ⌃⌥↑ and ⌃⌥↓ move to the tile beside (⌃⌥→ from the rightmost, and from a session in tabs, to the side pane when it shows the Board or a file; ⌃⌥← back), and ⌃⌥↩ zooms the tile you're in to the whole area and back. Tabs, tiles and the strip come back after a restart; terminals don't (their shells end with Magnum). The window has every part of the layout, with its keys.

Density

Comfortable, Compact or Dense sets how much of the conversation fits: Settings → Appearance → Density, ⌘P → Density, or ⇧⌘L. Dense uses the pane's whole width, with smaller text.