Files panel

The files panel shows the files of the active workspace in a column on the right of its panes: a tree to browse them, a viewer to read them in your terminal’s colours (and to see its images), and a bar to search their names or their text. Git’s marks are everywhere, so you see at a glance what an agent touched, and the lines you pick go back to the agent with a click.

The files of an issue worktree, with what changed marked in the tree.

Open and close it

Click Files at the bottom of the sidebar, under Issues, to open the panel, and again (or × in the panel, or Esc) to close it. It takes the same column as the changes panel, the TODO panel and the Flow panel, so only one of them shows at a time: opening one closes the others. Drag its left border to make it wider or narrower.

In the compact layout, a ▤ button in the top bar opens it over the whole screen, and a file shown full screen covers the top bar too.

The panel follows the active workspace, and each workspace keeps its own open folders, search and open file, so switching back finds them as you left them. Worktrees show their own files. The panel works in any folder, git or not; the marks need git.

Browse

The tree starts at the workspace’s folder, folders first. Click a folder to open or close it, a file to read it, and use the wheel to scroll. Hidden files such as .env are listed; files git ignores, such as target/ or node_modules/, are not. New files show up within two seconds, so you see what an agent creates as it goes.

In a git workspace, a changed file gets its status in its colour: M for modified, A for added or new. A folder holding changes gets a ●, yellow, or green when everything in it is new. The marks follow the project scope of the changes panel: what isn’t committed yet, or, when you pick Commits or All there, what the branch changed.

Read a file

Lines 11 and 12 changed; the lines they replaced are shown above them.

The header shows the file’s path, its number of lines and its language; ‹ goes back to the tree.

▢, left of ×, shows the file full screen, over the sidebar and your panes, so a long line or a big file has the whole window without dragging the border. ❐ or Esc puts it back in the panel, at the width it had. The file keeps its place, its selected lines and its highlights both ways, and the wheel, the lines, open, ask agent and copy work as in the panel. Going back to the tree, closing the panel, open, ask agent (when it finds an agent) and switching to another tab also put it back. Your programs keep their size and keep running underneath.

The same file full screen; the restore button is left of the close button.

Code is coloured with your terminal’s palette by tree-sitter grammars, for about 60 languages. A language without a grammar of its own borrows a close relative’s, so its comments and strings still read right. Files over 2 MB show without colours.
Beside the line numbers, git’s marks show what changed: a green ▎ on added lines, a blue ▎ on changed ones, and a red ▁ under the line after which lines were deleted (▔ when they were at the top). A new file is green all the way down.
Click the mark of a changed or deleted block to see the lines that were there before, in red, and again to hide them.
The viewer follows the file on disk: when an agent edits it, you see the new version within a second, marks included.
Images show as pictures. Other binary files, files over 8 MB and files that are gone say so instead of showing their content.

To change a file, use open: the panel only reads.

Pick lines and act on them

Click a line to select it, or press and drag over several. Hold the pointer on the first or last line shown, or past it, and the file scrolls while the selection follows; the wheel scrolls it too while you keep the button pressed. The header says which lines, such as lines 11-12, and its buttons act on them:

Button	Does
open	Opens the file in a new tab with your `$VISUAL` or `$EDITOR` (or `vi`), at the first selected line. The tab closes when you quit the editor.
open in…	A menu of your apps: file manager or Finder, VS Code, Cursor, Zed, Sublime Text when installed, and default app. An editor opens the file at the first selected line; default app opens it with the app your system picks, such as Preview for an image. It shows only on this computer (a remote window offers copy path), and a narrow panel leaves it out; the tree’s right-click still has it.
ask agent	Types a reference such as `src/returns/address.rs:11-12` into the agent running in this workspace and switches to its tab, so you can write your question after it. With nothing selected it types the file’s path. Without an agent in the workspace, it copies the reference to your clipboard instead.
copy	Copies the selected lines to your clipboard, or the whole file when nothing is selected, exactly as it is on disk (tabs included).

Images

Click a PNG, JPEG, GIF, WebP, BMP or ICO file and the viewer shows the picture itself, drawn by your terminal. cornercase knows an image by its content, not by its name; an SVG file is text, and shows as text.

The header says what the file is: its format, its size in pixels and its size on disk, such as PNG · 1280×720 · 245 KB.
The picture sits under the header, centred, made smaller to fit the panel and never larger than it is, so an icon stays small. Drag the panel’s border, or click ▢, to see it bigger.
An animated GIF or WebP shows its first frame.
The viewer follows the file: when an agent saves a new screenshot over it, you see the new picture within a second.
ask agent types the image’s path, such as docs/returns-page.png , into the agent running in the workspace, which can open the image itself; copy copies the path. An image has no open and no lines to select, but it has open in…, where default app shows it in Preview or your image viewer.
While a dialog is open, such as the settings, the picture is hidden: a terminal can’t dim a picture the way it dims text. Menus and the search show over it as usual.
A file cornercase can’t decode says why instead, such as cannot read this image: ….

Each window draws pictures with its own terminal. With two windows attached to one server, say Ghostty on your desk and another terminal over SSH, each shows the picture the way its terminal can, and a window whose terminal can’t shows why in its place. Over SSH and with cornercase remote, the picture travels to the terminal in front of you, so a large one can take a moment on a slow link.

Which terminals show them

Terminals draw pictures with one of three protocols. When it starts, cornercase asks your terminal for its name, which works over SSH too, and picks the one your terminal understands; there is nothing to set.

Terminal	Protocol	What it needs
Ghostty	kitty graphics	Any version.
kitty	kitty graphics	0.28 or later.
Rio	kitty graphics	0.5.27 or later; before that, iTerm2 inline images.
iTerm2	iTerm2 inline images	Your OK the first time; see iTerm2 asks first.
WezTerm	iTerm2 inline images	Nothing.
Warp	iTerm2 inline images	Nothing.
VS Code, Cursor	iTerm2 inline images	`terminal.integrated.enableImages` turned on in the settings.
Tabby	iTerm2 inline images	Settings › Terminal › Sixel turned on.
foot	sixel	On unless `foot.ini` says `sixel=no`.
Konsole	sixel	22.04 or later.
xterm	sixel	Running as a VT340: `xterm -ti vt340`.
mlterm	sixel	Built with sixel.
Contour	sixel	Nothing.

With kitty graphics, cornercase draws the picture as the panel’s own cells (kitty’s Unicode placeholders), so it goes through tmux and anything drawn over it, such as a menu, covers just that part.

Alacritty, Terminal.app, GNOME Terminal and the other terminals built on VTE (Ptyxis, Console, Tilix, Terminator, xfce4-terminal), st, urxvt and the terminal of JetBrains IDEs can’t show pictures. The panel says so where the picture would be, and names terminals that can.

iTerm2 asks first

The first time a program shows a picture, iTerm2 asks Allow Terminal-Initiated Display? Allow it, and let iTerm2 remember your answer so it doesn’t ask again. Until you answer, the picture doesn’t show.

If you once declined and told iTerm2 to remember, it shows no pictures and says nothing about it: allow them again in iTerm2 › Suppressed Alerts (iTerm2 3.7 or later). With iTerm2’s Disable potentially insecure escape sequences turned on, it shows 🚫 instead of the picture.

Inside tmux

tmux shows pictures in one of two ways, depending on your terminal. Ghostty, kitty and Rio get them passed through, which tmux allows only with allow-passthrough; a terminal with sixel gets them drawn by tmux itself, which needs a tmux built with sixel and no setting (both are described below). For passthrough, add this line to ~/.tmux.conf, or to ~/.config/tmux/tmux.conf if that is where yours is:

set -g allow-passthrough on

Load it into the running tmux, then quit cornercase with Quit and start it again, since cornercase checks your terminal when it starts:

tmux source-file ~/.tmux.conf

tmux show -g allow-passthrough says whether it took: on or all, or 1 on tmux 3.3. With on, tmux drops a picture sent while cornercase’s window isn’t the one tmux shows. Use all instead (tmux 3.4 or later) so pictures arrive even then.

When cornercase runs on another machine, reached with SSH from inside tmux, it asks the terminal through tmux when it starts. If its pane was hidden or wasn’t the active one at that moment, no answer comes back: start cornercase again in a pane you are looking at.

Ghostty, kitty and Rio show pictures through tmux, also when cornercase runs on another machine you reach with SSH from inside tmux.
Terminals with sixel, such as foot, Konsole, WezTerm or iTerm2, show them when tmux itself was built with sixel (tmux 3.4 or later; Ubuntu’s and Debian’s packages are): tmux then draws the pictures. A tmux without sixel says this tmux (…) cannot draw sixel images.
iTerm2 inline images don’t survive tmux’s own redraws, so cornercase doesn’t send them through tmux. A terminal that only has them, such as Warp, shows no pictures inside tmux: run cornercase outside tmux there.
tmux inside tmux doesn’t pass pictures through.

GNU screen and Zellij

GNU screen can’t pass pictures through: run cornercase outside screen, or in tmux.

Zellij 0.45 or later draws sixel pictures itself, so in a terminal with sixel, such as foot, Konsole, WezTerm or xterm as a VT340, cornercase shows them inside Zellij. Older versions claim sixel whatever the terminal can do, so cornercase can’t tell and shows none: update Zellij. kitty graphics and iTerm2 inline images don’t pass through Zellij: in Ghostty, kitty, Rio, iTerm2 or Warp, run cornercase outside it.

Another multiplexer that cornercase only knows by its TERM, such as screen-256color without GNU screen’s variables, doesn’t pass pictures either.

Choose the protocol yourself

Some terminals can show pictures but don’t tell who they are, such as Blink Shell and a-Shell on an iPad, which understand iTerm2 inline images. Set CORNERCASE_IMAGES when you start cornercase to choose the protocol yourself:

CORNERCASE_IMAGES=iterm cornercase

Value	Pictures are drawn with
`kitty`	kitty graphics, with Unicode placeholders.
`iterm` or `iterm2`	iTerm2 inline images.
`sixel`	sixel.
`off`	Nothing: this window shows no pictures.

The variable belongs to the window, not to the server: each cornercase you start reads its own, so two windows on one server can use different values, and with cornercase remote it’s the one on your own machine that counts. A protocol your terminal doesn’t understand shows nothing, or stray characters, where the picture would be: start cornercase without the variable to go back.

When a picture doesn’t show

The panel says why where the picture would be, and what to do. The messages, with what they mean:

The panel says	What to do
`images need tmux to pass them through`	Allow passthrough as in Inside tmux, in `~/.tmux.conf` or `~/.config/tmux/tmux.conf`, run `tmux source-file` on that file, then start cornercase again. `all` instead of `on` (tmux 3.4 or later) also lets pictures arrive while the window is hidden.
`inside tmux, images need set -g allow-passthrough on`	No answer came back through tmux. Allow passthrough as in Inside tmux. If it is on already, cornercase’s pane was hidden or not the active one when it started: start it again there (`all`, tmux 3.4 or later, also covers a hidden window). Otherwise the terminal running tmux can’t show pictures.
`cornercase cannot show images in … through tmux`	Ghostty, kitty and Rio can show pictures through tmux; outside tmux, more terminals can. See Inside tmux.
`this tmux (…) cannot draw sixel images`	Your terminal has sixel, but this tmux wasn’t built with it. Use tmux 3.4 or later built with sixel, or run cornercase outside tmux.
`images do not pass through tmux inside tmux`	Run cornercase in the outer tmux, or outside tmux.
`GNU screen cannot pass images through`	Run cornercase outside screen, or in tmux with `set -g allow-passthrough on`.
`this multiplexer (TERM=…) cannot pass images through`	Run cornercase outside it.
`cornercase shows images in Zellij only as sixel, and this terminal has no sixel`	Run cornercase outside Zellij, or in a terminal with sixel, such as foot, WezTerm or Konsole.
`Zellij … claims sixel whatever the terminal can do, so cornercase cannot tell`	Update Zellij to 0.45 or later, or run cornercase outside it.
`Ghostty did not answer the image query: its image-storage-limit is 0`	Remove `image-storage-limit` from Ghostty’s config (the default is 320000000), reload it (`ctrl+shift+,`, or `cmd+shift+,` on macOS), then start cornercase again.
`kitty … is too old for images in cornercase`	Update kitty to 0.28 or later.
`Konsole … cannot show images`	Update Konsole to 22.04 or later.
`xterm shows images only when it runs as a VT340`	Start it with `xterm -ti vt340`, or add `XTerm*decTerminalID: vt340` to `~/.Xresources` and run `xrdb -merge ~/.Xresources`.
`sixel images are turned off in foot`	Remove `sixel=no` from the `[tweak]` section of `foot.ini` and restart foot.
`VS Code's terminal shows images only with terminal.integrated.enableImages on`	Turn it on in Settings (it also needs `terminal.integrated.gpuAcceleration`), open a new terminal and start cornercase again. Cursor shows the same message and has the same setting.
`Tabby shows images only with its Sixel setting on`	Turn on Settings › Terminal › Sixel, then start cornercase again.
`WezTerm did not report the window's size in pixels, so it shows no images`	Run cornercase in a local WezTerm tab rather than through a WezTerm multiplexer domain.
`the terminal did not report its cell size in pixels, which sixel images need`	Run cornercase directly in the terminal: mosh and some multiplexers hide the window’s size in pixels.
`… cannot show images`	This terminal can’t draw pictures, such as Alacritty, Terminal.app, GNOME Console or mlterm without sixel. Ghostty, kitty, WezTerm, iTerm2, Konsole and foot can; see Which terminals show them.
`this terminal cannot show images, or cornercase could not tell which terminal it is`	Ghostty, kitty, WezTerm, iTerm2, Konsole and foot can show them. If yours can, start cornercase with `CORNERCASE_IMAGES=kitty`, `iterm` or `sixel`; see Choose the protocol yourself.
`cornercase does not know how to show images in …`	The terminal said its name, but cornercase doesn’t know it. If it can show pictures, choose the protocol yourself.
`images are turned off in this window`	`CORNERCASE_IMAGES=off` was set when cornercase started: start it without it to see them.
`cannot read this image: …`	The file isn’t an image cornercase can decode, it is damaged, or it is too large (over 16384 pixels on a side).

Search

The bar at the top of the panel searches the whole workspace, skipping what git ignores. Click it and type: what you type goes to the bar instead of your pane, and results show as you type. An empty bar shows the tree again.

Searching the text: every matching line, grouped by file.

By default it searches the text of the files: each line that holds what you typed, grouped by file, with what matched highlighted. Case is ignored unless you type an uppercase letter. Binary files are skipped, and the search stops at the first 1,000 matches. Opening a match opens the file at that line, selected, with every match highlighted.

Click ▤ at the right of the bar to search file names instead, and again to go back to the text. Type the letters of a path in order: retadd finds src/returns/address.rs. The best 200 files show, best first, with the letters that matched in cyan; between two equally good matches the shorter file name wins, so workspace-session puts workspace-session.ts before workspace-session-handler.ts.

Keys	Do
Type, paste, `Backspace`	Change the search.
`↑` `↓`	Pick a result.
`Enter`	Opens the picked result.
`Esc`	Clears the bar and gives the keys back to your pane. On an empty bar, closes the panel.

× in the bar clears it too. A click in a pane gives the keys back and keeps the search; a click on the bar takes them again.

Paths in your panes are links

When a program prints the path of a file, hovering it underlines it, and clicking it opens the file in the files panel, opening the panel if it was closed. Claude Code’s Update(src/app.rs), a compiler’s src/main.rs:12:5, git status and grep -n all work, as do files outside the workspace such as /tmp/report.md, ~/.claude/plans/fix.md or a file in another project or worktree.

A line number after the path opens the file at that line, selected, so ask agent takes it at once: :12, :12:5, a range like :12-20, or GitHub’s #L12-L20.
A relative path is looked up from the folder of the program that printed it, then from the workspace’s root. A leading ~/ expands to your home folder. Only regular files are links: folders, devices such as /dev/zero and FIFOs aren’t opened.
Files inside the workspace keep their relative path. An outside file shows its absolute path, which open and ask agent use too. It has no git marks. ‹ returns to the tree or your previous search results; the panel remembers the outside file when you close and reopen it, until the server stops.
In a program that doesn’t use the mouse, pressing and dragging over a path still selects text, as anywhere else.
In a program that uses the mouse, such as Claude Code in its full-screen mode, a click on a path that releases on the same spot opens the file, and the program doesn’t see it; if you drag, the program gets the press and the drag as usual.