How do I resize the Brain drawer and run more than one brain?

In Codus 0.2.204 or later the Brain drawer sits on the left edge of the window, and from 0.2.207 you can move it to the right (see Choose which side the Brain opens on). Drag its inner edge to make it wider or narrower, and codus remembers that width the next time you open it. To run more than one brain, use the tabs across the top of the drawer and the + button beside them; each tab is a separate brain with its own conversation. The menu button (three lines) at the right end of the tabs lists every brain, and Pin as sidebar turns that list into a column down the side of the drawer. Closing the whole drawer (the brain button in the title bar, or the Esc key) hides the panel but keeps every brain running, so your conversation is still there when you reopen it. Closing a single brain tab does something different: it ends that brain's session for good, so codus asks you to confirm first.

Before you start

Open the Brain drawer. Click the brain button (a brain icon) at the top left of the codus window, just before the codus name (in Codus 0.2.204 and earlier it sat at the right end of the title bar, next to the settings gear). If you moved the Brain to the right, the button sits at the far right end of the title bar instead. It is a switch: click it again to close the drawer, and it stays highlighted while the drawer is open. The drawer slides in from its edge of the screen (the left unless you moved it) and pushes the rest of your work over to make room. If it is already open, you are ready.

Choose which side the Brain opens on

In Codus 0.2.207 or later the Brain can open on the left or the right. The left is the default.

1. Click the menu button (three lines, tooltip All Brains) at the right end of the Brain's tabs.
2. Click Move to the right. The drawer moves to the right edge and the brain button moves to the far right of the title bar. Choose Move to the left in the same menu to move it back.

The same choice is Brain side in Settings → Appearance, with a small picture for Left and Right. Codus 0.2.204 to 0.2.206 always put the Brain on the left, and earlier versions always put it on the right.

Resize the drawer (make it wider or narrower)

The drawer has a thin drag handle running down its inner edge: the right edge when the Brain is on the left, the left edge when it is on the right. You work it with your mouse. The steps below are for a Brain on the left; on the right, use its left edge and drag the other way.

1. Move your pointer to the right edge of the drawer, where it meets the rest of the window. The edge tints blue and your pointer turns into a left-and-right arrow. Hovering there shows the tooltip Drag to resize.
2. Press and hold the mouse button, then drag right to make the drawer wider, or left to make it narrower. The work to the right of the drawer reflows to match as you drag.
3. Let go when you are happy with the width.

The drawer opens at 380 pixels wide the first time. You cannot drag it narrower than 300 pixels, and you cannot drag it wider than 65% of the codus window, so it can never take more than about two-thirds of the screen. When the brain list is pinned as a sidebar, the list counts towards that 65% too. codus saves the width you choose and uses it every time, even after you quit and reopen the app. If you want the drawer wider than the limit allows, make the codus window bigger first.

What the buttons along the top do

Along the top of the drawer, from left to right, you will see:

• The brain tabs, one per brain, starting with Brain 1. The tab you are viewing is highlighted.
• The + button, right after the last tab. Its tooltip reads Add another brain.
• The menu button (three lines) at the right end. Its tooltip reads All Brains. Click it for a list of every brain, with New Brain and Pin as sidebar at the bottom.

Below the tabs is a second row with session, tasks, done and notes, and the globe button at its right end. The globe shows or hides the Brain's own browser; its tooltip flips between Show Brain browser and Hide Brain browser. See the Brain's Live View browser.

In Codus 0.2.204 or later the camera button and the artifacts button are no longer along the top. They sit in the bottom bar as small icons, and the small i help button has been removed. See Records, Assets and provider settings below.

These tabs and buttons are ordinary buttons you click with the mouse. That is different from the big terminal panel lower down, where clicking does nothing and you use the arrow keys and Enter instead.

See every brain in one list

When you have more brains than fit across the top, the tabs scroll sideways. The menu shows them all at once.

1. Click the menu button (three lines, tooltip All Brains) at the right end of the tabs.
2. A list of every brain drops down, each with its colour dot. Click a brain to switch to it.
3. Click New Brain to add one, or Pin as sidebar to keep the list open down the side of the drawer.
4. Click anywhere else, or press Esc, to close the menu without choosing.

Pin the brain list as a sidebar

Pin as sidebar replaces the tabs along the top with a column titled Brains down the outer side of the drawer (the left when the Brain is on the left, the right when it is on the right), one brain per row, like a list of chats. The column is added beside the session, so it does not squeeze the terminal.

• Click a row to switch to that brain. Double-click a row to rename it, and right-click it for colour and project settings, the same as a tab.
• The + next to the Brains title adds a brain.
• Drag the column's inner edge to make it wider or narrower (tooltip Drag to resize, double-click to reset). It goes from 110 to 360 pixels wide. Double-click that edge to put it back to its starting width of 148 pixels.
• Click Show as tabs at the bottom of the column to go back to tabs across the top.

codus remembers whether you chose tabs or the sidebar, and the column's width.

Change the order of your Brains

In Codus 0.2.208 or later you can put your brains in any order.

1. Press on a brain's tab and drag it left or right along the top of the drawer. If the list is pinned as a sidebar, drag a row up or down the Brains column instead.
2. A line appears between the tabs (or rows) to show where the brain will land. Let go to drop it there.

With the keyboard, click a brain's tab or row, then hold Option and Shift (Alt and Shift on Windows) and press the left or right arrow key (up or down in the sidebar) to move it one place.

The All Brains menu follows the same order. codus saves it straight away and keeps it after a restart, and once your computer has synced, the Codus iPhone app lists your brains in the same order.

Close the drawer vs close a brain

These two look alike and do very different things. This is the part that catches people out, so read it once more if it feels fiddly.

• The brain button in the title bar hides the panel, and pressing Esc does the same. Every brain keeps running in the background. When you reopen the drawer, each brain's conversation replays exactly where it left off. Nothing is lost.
• The × on an individual brain's tab (tooltip Close this brain) is the destructive one. It ends that brain's session for good. Because that cannot be undone, codus shows a confirmation first that reads: Close Brain 2? Its agent session ends. You can add a new brain any time. Click OK to end it, or Cancel to keep it.

Esc closes the drawer, unless you are typing. If your cursor is in a text box or a terminal, Esc goes there instead, so it can never swallow a keypress meant for your brain. If the Brain settings popup is open, Esc closes that popup first.

Run more than one brain

You can have several brains open side by side, each working on its own thing.

1. Click the + button (tooltip Add another brain) at the top of the drawer, or New Brain in the menu.
2. A new tab appears, named Brain 2 (then Brain 3, and so on), and it becomes the active tab. It has its own separate conversation, its own working folder, and its own browser preview, with nothing carried over from the other brains.
3. To rename a tab, double-click it. The tab turns into a small text box. Type the name you want and press Enter, or click anywhere else, to save it. Press Esc to cancel. If you leave it blank, the tab keeps its old name. Names are capped at 40 characters.
4. To switch between brains, click a tab. The terminal below swaps to that brain's conversation and replays what it has said so far, and the browser preview swaps to that brain's page.
5. To close a brain you no longer need, click the × on its tab and confirm. That brain's session ends.

Brain 1 is permanent. It has no × and cannot be closed, because it is the default brain that receives messages sent from your quadrant agents. (For how those messages work, see the related pages.) You can still rename Brain 1 by double-clicking its tab.

Your set of brains and their names are saved. Quit codus, open it again, and the same tabs are waiting for you.

Records, Assets and provider settings

Each Brain has session, tasks, done and notes tabs. They are separate from project-sidebar records; see Brain records and their lifecycle and sync and conflict choices.

The bottom bar of the drawer holds, from left to right: the Agent and Chat view picker, the provider selector, the Brain settings button (a gear) for model and reasoning, the camera button (tooltip Send a photo from your phone to this Brain), and the artifacts button (tooltip Open artifacts (drawings, diagrams, charts)). In Codus 0.2.204 or later the camera and artifacts buttons are icons only. The artifacts button opens the selected Brain's asset library beside the drawer; click it again, or the × on the panel, to close it.

The bottom bar selects the provider, model and supported reasoning settings. Read provider and model selection before changing a live session. Hiding the drawer is not the same as quitting Codus or closing a Brain tab.

How do I know it worked?

• After resizing: the drawer is visibly the width you set, and when you close and reopen it (or restart codus) it comes back at that same width.
• After adding a brain: you see two or more tabs (or rows, if the list is pinned as a sidebar), the new one is highlighted, and the panel below shows a fresh conversation with nothing from the other brains in it.
• After renaming: the tab shows the new name, and it is still there after a restart.
• After changing the order: the tabs or rows stay in the new order after a restart, and the iPhone app shows your brains in that order too.
• After closing a brain tab: the tab is gone and only the brains you kept remain.
• After closing the drawer: the panel slides away, the brain button in the title bar stops being highlighted, and clicking it brings the panel and your conversation straight back.

Common problems

I pressed Esc and the drawer stayed open. Your cursor was in a text box or a terminal, so Esc went there instead. Click somewhere neutral in the drawer and press it again, or use the brain button in the title bar.

Brain 1 has no × to close it. That is on purpose. Brain 1 is the permanent, default brain and cannot be closed. You can rename it by double-clicking its tab, but you cannot remove it.

Double-clicking a tab did not rename it. Double-click the tab itself, not the small × on it. A single click only switches to that brain. When the rename starts, the tab becomes an editable text box.

I closed the drawer and thought I lost the conversation. You did not. Closing the drawer keeps every brain running. Click the brain button in the title bar to reopen it, and the conversation replays.

A brain will not drag. Drag the tab or row itself, not its ×, and finish any rename first (a tab being renamed is a text box). Dragging brains needs Codus 0.2.208 or later; check Settings → Updates for your version.

I cannot find the brain tabs. The list is pinned as a sidebar. Look for the Brains column down the outer side of the drawer, or click Show as tabs at its bottom.

The drawer is on the other side of the window. In Codus 0.2.207 or later, use Move to the left or Move to the right in the Brain's menu, or Brain side in Settings → Appearance. Codus 0.2.204 to 0.2.206 always put the Brain on the left, and older versions put it on the right. Check Settings → Updates for your version.

The drawer will not get any narrower or wider. There are limits. It stops at 300 pixels when you drag in, and at 65% of the window when you drag out. Make the codus window bigger if you need the drawer wider than that.

It asks for a supported coding agent. Choose an installed provider in the Brain's bottom bar, or follow Brain setup. Claude Code is not compulsory. Provider installation and sign-in are separate checks.