Features

Sidebar

• Every session under ~/.claude/projects/, grouped by project with collapsible headers (and one header-bar toggle that collapses every group, or opens them all again). Which projects are expanded is remembered across restarts.
• Drag a project header up or down to rearrange projects; the order is yours and persists (new projects join the list alphabetically).
• A Favorites section pinned on top — star any session to move it there.
• Compact single-line rows: name, relative time, status — with an optional second line showing the project folder path (Preferences → Show folder path). Within a project, sessions sort by creation time, newest first, so rows don't jump around as sessions produce output.
• Row actions on hover — pointing at a row swaps its timestamp for its buttons, so a row shows either when it last ran or what you can do with it: archive on every row, preceded by stop (exit the agent and close its tab) and background (detach with /bg, leaving it running) on the sessions that have a tab open.
• A + button on every project header starts a new session in that project; right-click a header for New session here and Archive project. Projects whose sessions are all archived or favorited still show their header, so the folder stays reachable.
• Open a project's folder anywhere else from that same right-click menu: one row per app you added under Preferences → Footer apps, each with its own icon, plus Open in File Manager and Open in Terminal for whichever apps your desktop nominates for those jobs ($TERMINAL, xdg-terminals.list, and the system's own x-terminal-emulator are honoured, in that order). The Chats group has no folder of its own, so its menu stays as it was.
• A search button that opens a search box across the sidebar header, filtering by name, project, message preview, or session ID, plus a footer showing session, project, transcript-size, and open-tab counts.
• Live updates — sessions appear and reorder as they're created or written to, via a filesystem watch. A just-started session shows a "New Thread" placeholder row until the agent writes its transcript.
• Quick switcher (Ctrl+Shift+K) — a type-ahead dialog to jump to any session by name, project, preview, or ID.
• Running sessions are filled in: a session with a tab open gets a fill, so live work stands out from the archive of past sessions — read or unread, the fill is the same. The session shown in the selected tab takes the peach highlight.
• A yellow guide line marks a session running detached in the background (/bg) — no fill, because there is no tab to return to; reopen the row to re-attach.
• A moving barber pole marks a session in a tab whose agent is working right now: the row's guide line turns into blue stripes climbing while output is flowing, and goes still a couple of seconds after the agent stops — so a glance down the sidebar says which sessions are thinking and which are waiting on you. Collins reads the tab's terminal for this, so only sessions with a tab pole; a detached session's yellow line stays put whatever its agent is doing. The pole follows the desktop's animation setting: with animations off, the line simply stays put.
• Waiting badge — an amber ? marks sessions where the agent's last message was a question awaiting your reply, so you can spot what needs you at a glance.
• Interrupted badge — a red stop icon marks sessions you stopped mid-task.

The search button (or Ctrl+Shift+F) opens the search box across the sidebar header, and it filters the whole list as you type — the X closes it again and restores the unfiltered list:

Auto-generated titles

Unnamed sessions get a title generated for them:

• Sessions that already existed when the app launched are titled locally (the first 10 words of the initial prompt) — the model never sees your backlog.
• Sessions created while the app is running have their first prompt summarized to five words or fewer by a headless claude -p --model haiku run — the same CLI and login the whole app is based on, no extra credentials needed.

Titles are persisted so each is generated only once; right-click → Regenerate name re-runs the model for one session, and a Preferences toggle turns auto-titling off. A manual rename always wins.

Quick switcher

Press Ctrl+Shift+K anywhere to fuzzy-jump to a session — arrow keys move, Enter opens, Esc closes.

Custom names, favorites & emoji

• Give any session a custom name (right-click → Rename…, or rename its tab — the name syncs everywhere).
• Star sessions to pin them to Favorites.
• Add an emoji prefix to a tab (right-click a tab → Set emoji…, or Ctrl+Shift+E for a quick 😊 marker).

All of this is stored in ~/.config/collins/state.json. Your agents' own session files are never modified.

Tabs & terminals

• Clicking a session opens a tab with an embedded VTE terminal running your $SHELL with the agent's resume command (claude --resume <id> for Claude Code) — in the directory the session last worked in (worktree-aware), not just where it started.
• If the session is still running detached (e.g. after backgrounding it), Collins re-attaches to the live process (claude attach) instead of resuming a copy.
• A tab with unread output is marked by the tab bar itself; tabs carry no status dot of their own.
• Tabs sit in the sidebar's order — left to right is exactly the session list read top to bottom, whatever order you opened them in, and they re-arrange when the list does (a project dragged to a new spot takes its tabs with it). Chats and replays, which have no row in the list, collect at the right-hand end. The tab bar can't be dragged into a different order for that reason: reorder the projects in the sidebar instead.
• A slim tab footer shows the agent's live working directory (click to copy) and the current git branch (⎇), plus the terminal-panel buttons.
• Pull request chips trail the branch: one per PR the session has opened, each with its CI mark (✓ / ✗ / ●) or GitHub's merge mark, and each opening that PR on click. The caret beside them lists every one with its title — the same list a sidebar row's GitHub button opens.
• Right-click a chip (or a PR in either list) for what to do with it: mark a draft ready for review, merge it — or turn on auto-merge while its checks are still running — or ask Claude for a review (a @claude review comment, for repositories running the Claude Code GitHub action). Left-clicking still opens the page, which is why nothing in the menu does; a PR with nothing left to do says so rather than opening empty.
• Two of those items are sent to the session as a prompt instead of run against GitHub: address the CI errors, when that PR's CI is red, and open pull request, once it has merged and the terminal's working directory has uncommitted changes again — your work landed, and what is in the tree now wants a PR of its own. Both are only offered while the session is open and sitting at an empty prompt, so a half-written line of yours is never sent along with it (and a permission dialog, which takes Enter too, is never answered by it).
• Rename tabs, copy the session ID, or fork a session (--fork-session) from the right-click menu.
• Shift+Enter inserts a newline in the agent's prompt.
• In-terminal search (Ctrl+Shift+G) over the scrollback.
• Easy copy & paste (on by default): plain Ctrl+C copies whenever text is selected — otherwise it interrupts the agent as usual — plain Ctrl+V pastes, and right-click opens a Copy / Paste / Select All menu. No Ctrl+Shift finger-twisting just because it's a terminal; the classic Ctrl+Shift+C / Ctrl+Shift+V always work, and the mode can be toggled in Preferences.
• Closing a tab asks the agent to exit cleanly (Claude Code's Ctrl+C Ctrl+C) in the background first, rather than terminating it. The quit keystroke rather than a typed /exit, because it works from whatever the agent happens to be showing — a permission prompt, the trust dialog, its session list — and not just from an empty prompt. For agents that support it, the close dialog also offers to background the session instead (Claude Code's /bg) — the agent keeps running detached, and reopening the session re-attaches to it. The same option appears when closing the whole window with active sessions, which hands the sessions over one at a time so each is correctly paired with the background agent it becomes.
• While a session tab is focused, two header buttons act on it directly, skipping the confirmation dialog: one exits the session and closes the tab, the other backgrounds it (shown only for agents that support detaching) and closes the tab.
• Backgrounding is greyed out until it is safe: a brand-new thread can't be backgrounded until Collins knows its session id, and no session can be backgrounded while another handoff is still waiting for the id its agent moved to. Both windows last a second or two; the tooltip says which one you are in. Backgrounding before then would detach an agent that nothing could find its way back to.
• The tab bar can be hidden with a header toggle — tabs and sessions keep running. While it is hidden the window title becomes the active tab's title, so the header (and alt-tab, and the dock) still names the session you are looking at; showing the tab bar again restores "Collins".
• On the next launch the app reopens the session you had focused when you closed the window, and the window comes back at its last size.
• The sidebar is resizable (drag the divider) and its width is remembered.

Terminal panel

Every tab has a second, plain-shell terminal area — no agent auto-launched — that lives below or beside the agent terminal, with tabs of its own:

• Toggle it with Ctrl+J or the buttons in the tab footer; Ctrl+K clears it (screen and saved history).
• The panel's tab row has a + button that opens another shell tab and switches to it; each tab's ✕ closes it (and deletes its saved history), asking first if a command is still running in it. Closing the last tab hides the panel — the footer's terminal button brings it back with a fresh tab.
• Shells open in the agent's current working directory (worktree-aware), and the swap button moves the panel bottom ↔ right without restarting them.
• Right-click the footer's terminal button to open that same directory — the agent's live one, not the project root — in your desktop's own terminal instead, for the times a window of its own beats a panel. The terminal is whatever $TERMINAL, xdg-terminals.list or the system's x-terminal-emulator nominate (the same pick the sidebar's Open in Terminal uses), and the directory is handed to it on its own command line, so an already-running terminal opens where you asked rather than wherever it last was.
• Scrollback persists across restarts, per panel tab — reopen a session and the panel picks up where it left off, every tab in place, with a "restored panel history" marker.
• Each session remembers its panel's open state, position, and size; the last-used position and size also become the default for new panels.
• Typing exit in a panel tab closes that tab (closing the last one hides the panel).
• Closing a session tab while a command is running in any of its panel's shells — even a hidden panel's — asks for confirmation before the command is killed.

Editor panel

A syntax-highlighted code editor lives beside the agent terminal — the "read and fix what the agent just did" surface, not a general-purpose IDE:

• Toggle it with F8 or the footer icon (a page with a folded corner, between the footer apps and the terminal-panel button) — one editor per tab, full-height in a right-hand column.
• A project file tree rooted at the tab's directory; click a file to open it in a tab strip of its own, with a dot marking unsaved changes.
• Quick open (Ctrl+Shift+O): fuzzy-find any file in the project by typing a few letters of its name or path — no digging through the tree.
• An Agent files list pinned above the tree: the files this session's agent has most recently written or edited, newest first, one click from the change it just made. It appears the moment the agent first writes a file.
• In a chat tab, a tool chip that names a file (an edit, a write, a read) becomes a link once the call's details arrive — click it to open that file in the matching session tab's editor.
• Real editing: line numbers, current-line highlight, bracket matching, undo/redo, and 180 languages' worth of syntax highlighting via GtkSourceView, the same engine behind GNOME Text Editor and Builder.
• Save with Ctrl+S or the status row's save button; find in the current file with Ctrl+F.
• External changes are the normal case, not the edge case — the agent is rewriting these files while you look at them. A clean buffer reloads silently, cursor and scroll preserved; a buffer with your own edits gets a banner instead, so nothing is overwritten without asking.
• The color scheme follows the app's light/dark setting by default, or pick one of GtkSourceView's bundled schemes in Preferences, along with the editor's font and whether the file tree shows hidden files.
• Each session remembers which files were open, the cursor in each, and the panel's width — restored the next time you reopen it.
• Pop it out to a second monitor with the status row's detach button (rightmost): the whole editor — open files, cursors, unsaved changes — moves into a window of its own, and the in-tab panel disappears until it comes back. Dock it back with the window's headerbar button, by closing the window, or with the tab's footer icon (while the editor is popped out, one click means "bring it back"). One editor per tab, in one place at a time; the popped-out window remembers its own size.

If the footer icon is greyed out, the GtkSourceView 5 library the editor is built on isn't installed — the .deb pulls it in automatically, but a source checkout needs it installed by hand (Debian/Ubuntu: gir1.2-gtksource-5, Fedora: gtksourceview5, Arch: gtksourceview5). Install it and restart Collins; the button's tooltip says the same.

Claude usage panel

Below the session list, a Claude usage panel shows your subscription limits — the 5-hour session window, weekly limits, and any extra-usage credits — as progress bars with "resets in…" countdowns. It reads the OAuth token the claude CLI already stores (never modifying it), refreshes every 5 minutes, and pauses while the window is minimized or the screen is locked. Toggle it in Preferences (Show Claude usage).

Knowing what's happening

• Desktop notifications when a background session goes quiet after producing output — click to jump straight to that tab. (Off by default; toggle in Preferences.)
• Session details (right-click → Details…): message and tool-call counts, models used, token totals, timestamps, transcript size — plus a recent activity peek of the last messages, so you can identify a session without resuming it. It also lists the MCP servers available to the project and which ones the session actually used.

• MCP servers browser (menu → MCP servers): a read-only view of every MCP server configured in ~/.claude.json, global and per-project.

Prompt cards

When the agent asks a structured question in the terminal, a native option card overlays it — answer with a click instead of typing a number.

Starting sessions

• New session (tab icon in the header, or Ctrl+Shift+T) starts a fresh agent session in the visible session's project — no dialog needed. With no session visible, it asks for a folder.
• Advanced new session (New Session menu): choose a model, a permission mode, or an extra directory (--add-dir).
• Continue the most recent session in a folder (claude --continue).

Bulk actions & housekeeping

• Select mode (sidebar menu → Select multiple sessions) to open, star, archive, or trash many sessions at once.
• Archive sessions you're done with (kept on disk, toggle "Show archived" to see them and restore any of them); archiving a session with an open tab closes the tab too. Whole projects can be archived from their header's right-click menu.
• Delete archived sessions… (sidebar menu) clears the lot in one go: every session the sidebar keeps out of sight — archived by hand, archived with its whole project, or replaced by a backgrounded fork — has its transcript moved to the trash. Archiving is cheap and the pile grows quietly, so the confirmation spells out the damage first: how many transcripts, in which projects, and how many of those projects lose every session they have. Greyed out when nothing is archived.
• Keeping a project after its sessions go: any dialog that would empty a project out offers "Keep the N emptied project(s) in the sidebar" (checked by default). Kept projects stay as empty headers with their folder, so New session here still works — they're remembered across restarts, and the header's right-click menu can Remove project from sidebar again. A project that gets real sessions back simply keeps its place.
• Export as Markdown (right-click) writes a session transcript to a readable Markdown file.
• Move a transcript to trash (recoverable) or delete it permanently — the only actions that touch a transcript file, and always behind a confirmation.
• Open in Ghostty to resume a session in an external Ghostty window instead of an embedded tab (shown when ghostty is on your PATH).

Caffeine Mode

The coffee cup at the right of the header keeps the computer awake and the screen on while an agent works unattended — click it to toggle, and the cup fills while it's on.

• Right-click it for a timer: 1 hour, 2 hours, 3 hours, 6 hours, 12 hours or Indefinitely. Picking a duration turns Caffeine Mode on for that long and turns it off again when the time runs out — so a long build can't leave the machine awake all week because you forgot.
• The time left counts down just left of the cup while a timer is running. Picking another duration restarts the clock, Indefinitely clears it, and turning Caffeine Mode off cancels it.
• Preferences → Turn on at launch starts every launch with Caffeine Mode on, and Turn off after arms one of the same durations at startup.

Multiple windows

Open additional windows from the New Session button's menu or with Ctrl+Shift+N. Windows share one session list and state, so favorites, names, and live updates stay consistent across them.

Preferences

Terminal font, scrollback size, easy copy & paste (on by default), a terminal color theme (Dracula, Solarized, Gruvbox, Nord, Catppuccin, Tokyo Night, Monokai, One Dark…), the editor's color scheme, font, and line numbers/hidden files toggles, the app's color scheme (system / light / dark), the language (English, Magyar, Deutsch, Español, Français), the sidebar's Show folder path, Show Claude usage, and Auto-generate session titles toggles, and the idle-notification toggle — reachable from the sidebar menu or Ctrl+,.