sessionview

A sidebar for tmux, in the spirit of herdr: your projects (tmux sessions) and your agents (seats), here and on remote hosts, one click away, with a right-click menu built from what is installed. Session's TUI — a controller and view for the session tools, drawn beside tmux.

Install from PyPI: uv tool install sessionview (see Install).

sessionview

In this terminal, that puts the sidebar on the left and the session main on the right; a private outer tmux holds the two panes. sessionview NAME attaches the session NAME instead, which must exist. In any tmux client, prefix H opens the same sidebar as a popup. Every verb, its form and an example: the sessionview command.

Read SPEC.md first: what sessionview is, the rules of the view, the contract with session, the plugin manifest, config, known limits. This repo is the reference implementation: session integrates from the spec; this stays comparable and runnable.

Requirements

• macOS (tested on macOS 27, Apple silicon)
• Linux
• WSL
• Windows

The direct dependencies and the tools a user meets, what needs each one, and how to upgrade it: dependencies.

Features

Grouped by component, named in the terms a comparison matrix would use.

Sidebar — projects (tmux sessions) above, agents (seats) below.

• Collapsible — the ◧ glyph at the far left of the tab bar hides it and shows it again; it keeps running, nothing restarts, and it comes back at the width it had.
• Resizable — drag the border. The width you drag to is remembered for the next open.
• Auto-sizing (fit: auto) — fits its contents: the widest row plus one, between width_min and width_max. Grows at once, gives width back after a few quiet redraws. Chrome never changes the width; only your content does. A drag switches back to a fixed width.
• Remote hosts — sessions and agents on other machines, over an ssh control master you already hold. The sidebar never opens a connection of its own, so a hardware key is never asked for a touch by a redraw.

Menus

• Overflow menu — three dots ⋯ at the right of the selected session open its menu (rename, new tab, config, settings, start an agent, close). Right-click opens the same menu on any row.
• Light dismiss — a click outside an open menu closes it, and so does a click into the main pane (focus leaves the sidebar).
• Keyboard — ↑↓ / j k move, the letter or enter picks, esc closes.

Tabbed windows — the tab bar on top: one tab per tmux window, the name once the window is named, the number until then; click to select, drag to reorder, + for a new tab, × to close (with a confirm). New tab - the +, or the session menu - is a picker: the session's standard windows (windows in config: repo, git, project, tasks, editor, shell) listed, typing narrows, enter opens the highlighted one or a plain tab of the name you typed. The same picker starts an agent (the + under agents, or the menu): the names session start knows, pinned ones first.

Agents

• Start an agent — + under the agents list, or Start an agent on a project's menu. The list you pick from is the launcher's own (session start --list-agents), so it cannot offer a name that will not start. An agent already running is never started twice.
• Agents have a home — an agent's own file says where it wakes (start: directory:); a project's menu starts it in the project.
• Consent on first open — Dreamcatcher asks once which agent to start when it opens (a numbered pick, or never), and remembers.

Settings — every setting, its default, its note and where its value comes from, in a small screen (project menu → Settings); the rows come from the template, so a new key needs no second edit.

Your terminal — the dock app opens sessionview in the terminal you use (terminal in config: iterm, ghostty or terminal), not whichever happened to be running.

Standard tmux — the frame is an outer tmux holding two panes; every view is a tmux session, window or pane. No daemon, no GUI toolkit, no tmux fork or plugin manager.

Terminals

Tested: Terminal.app, iTerm2, Ghostty (macOS). The sidebar needs mouse reporting and focus reporting from the terminal; anything that gives tmux those should work, but only the three above have been driven by hand. Blink Shell on iPad is wanted and not yet connecting.

Layout

bin/tmux-sidebar     the view, the clicks, the menus (Python 3.11+, stdlib)
bin/sessionview             the front door (the frame) + the sidebar supervisor
bin/sessionview-frame       the frame: outer tmux, sidebar pane + client pane
bin/sessionview-session     a project session with its configured tabs (repo / git / project / tasks)
bin/sessionview-newtab      the tab bar's "+": the new-tab picker, in a popup
bin/sessionview-config      settings: no verb opens the screen; list / get / set / unset / dump / path
bin/sessionview-autostart   the consent-on-open question; --start NAME is the + under agents
bin/sessionview-sidebar-toggle  hide / show the sidebar (the ◧ glyph)
bin/sessionview-terminal    which terminal the dock app opens
tmux/frame.conf       the sessionview look, session-scoped (sourced with S= and SESSIONVIEW_ROOT=)
tmux/tabs-top.conf   the same look, global and OPTIONAL (source-file it from ~/.tmux.conf
                     to have it outside sessionview too; the frame applies frame.conf itself)
config/config.json   every default, explicit; ~/.sessionkit/view/settings/view.json is made from it
plugins/*/           plugin.toml (+ scripts): session, voicemode, taskmaster
.claude-plugin/      sessionview is a Claude Code plugin; its skills load as
skills/*/SKILL.md    sessionview:NAME - sessionview, tmux, lazygit, neovim,
                     claude-code: short, safe driving skills with tools

Paths resolve from the checkout (SESSIONVIEW_ROOT); state lives in ~/.local/state/sessionview (SESSIONVIEW_STATE). Its direct dependencies: dependencies.

Install

From PyPI:

uv tool install sessionview
sessionview install

That puts sessionview, sessionview-config, sessionview-session and sessionview-messages on PATH; sessionview install then checks every requirement and links nothing.

From a checkout:

git clone https://github.com/sessionkit/sessionview ~/Code/sessionview
~/Code/sessionview/bin/sessionview-install

That links the tools into ~/.local/bin (make install in the checkout does the same) and checks every requirement, saying PASS / WARN / MISSING with the fix for each (tmux below 3.7 is the one that bites: an older tmux satisfies brew install tmux silently). It installs nothing else and never edits your shell config. sessionview-install --check reports without changing anything. Then, in a new terminal: sessionview.

The installer never moves links that already run another checkout (a second clone, a git worktree, or uv tool install's commands): it lists them, changes nothing and exits 3. --check lists the same links as WARN lines. Run bin/sessionview-install --relink from the checkout you want to run, or set PREFIX=DIR to install somewhere else. A bare make only lists the targets; installing is always make install.

The Claude Code plugin brings sessionview's skills. From a clone: claude plugin marketplace add <path-to-clone>, then claude plugin install sessionview@sessionview.

show-me (github.com/mbailey/show-me) is referenced, not bundled.

Dock app (macOS, optional)

sessionview install --app

That builds SessionView.app from macos/SessionView.applescript and puts it in ~/Applications (make app in a checkout does the same); drag it to the Dock and one click opens sessionview in your preferred terminal (see Terminals above). It is a front door, not the product -- sessionview in any shell does the same job.

On a cold click the app reuses the window Terminal opens for itself at launch, rather than adding a second one. If your Terminal profile runs a command of its own (Settings > Profiles > Shell > Run command) that window is busy, so the app opens its own and you get two.

Full screen on click is off by default; turn it on with

sessionview-config set fullscreen true

On Terminal.app that needs Accessibility permission for SessionView (System Settings > Privacy & Security > Accessibility) -- the app asks in a dialog the first time rather than failing quietly. iTerm and Ghostty need no permission.

Rebuilding the app (make app) gives it a fresh ad-hoc signature, which macOS treats as a different app -- so the Accessibility permission has to be granted again after every rebuild. A stable signing identity would fix that; the app does not have one yet.

What an install changes

uv tool install sessionview changes two places and fills uv's own cache, and it touches no shell startup file and nothing in ~/.claude. sessionview install after it checks the requirements and changes nothing. Everything else below appears only when you run the verb named beside it. Each line says what puts it there and what takes it away.

• PATH: ~/.local/bin/sessionview, sessionview-config, sessionview-session and sessionview-messages, or in UV_TOOL_BIN_DIR when that is set. uv says so if the folder is not on your PATH, and edits no shell file. uv tool uninstall removes them. From a checkout instead, bin/sessionview-install (or make install) links the checkout's bin/sessionview* tools and tmux-sidebar into ~/.local/bin, or into PREFIX/bin when PREFIX is set, and makes nothing else. Uninstall has the line that deletes them.
• The program: ~/.local/share/uv/tools/sessionview/, its own Python environment, or in UV_TOOL_DIR. sessionview has no Python dependencies: the environment holds sessionview and the files it ships (its tools, the tmux confs, the sidebar's plugins and the Dock app's source). uv tool uninstall removes it. If uv finds no Python 3.11 or newer, it downloads one into its own folder (uv python dir, ~/.local/share/uv/python/ by default). uv tool uninstall leaves that Python; uv python uninstall removes it.
• uv's cache: the install fills it with what it downloaded and built. It is uv's, shared by everything uv installs, not sessionview's. uv cache dir prints where it is (~/.cache/uv by default, or UV_CACHE_DIR). uv tool uninstall leaves it; uv cache clean sessionview drops this package's entries, and uv cache prune drops the ones nothing uses.
• Folders, each made by a verb you run:
  • ~/.local/state/sessionview/: the state folder, made the first time sessionview opens (or sessionview session or sessionview messages runs). SESSIONVIEW_STATE moves it. An older release's ~/.local/state/herd/ is renamed to it then, when only the old one exists. In it:
    • frame-PID.tty, one while each frame is open. The frame deletes it when it closes; a frame killed outright can leave it behind.
    • sessionview.log, the log (Logs).
    • recent.tsv, a line each time sessionview session opens a project, for the picker's order.
    • picker-order, when you flip the picker's sort.
    • sidebar-mail.txt, the last message typed at the sidebar's message prompt.
    • plugin-PLUGIN-ACTION.txt, the text a plugin's menu item last sent (the session plugin's Message or Continue, say), one for each item you have used.
    • sidebar-remote-HOST.json, what the sidebar last saw from each host in your remotes setting.
    • mutt/, an rc file for each box sessionview messages opens.
  • ~/Applications/SessionView.app: sessionview install --app (or make app in a checkout), or in DEST when that is set. It is built in a temporary folder that is deleted after, and a rebuild replaces it.
• Services (launchd agents): none. sessionview runs no daemon and writes nothing in ~/Library/LaunchAgents/. While a frame is open it runs a tmux server of its own, sessionview-frame, beside yours; the server exits when the last frame closes.
• Plugin and skills, optional: claude plugin marketplace add and claude plugin install (Install). Claude Code names the marketplace and the plugin in ~/.claude/settings.json (extraKnownMarketplaces, enabledPlugins), lists them in ~/.claude/plugins/, and keeps a copy in ~/.claude/plugins/cache/sessionview/. The plugin brings five skills (sessionview, tmux, lazygit, neovim, claude-code) and no hooks. Uninstalling the plugin takes it out of the settings and leaves the cached copy. The sidebar's own plugins (plugins/: session, taskmaster, voicemode) ship inside the program and install nothing. SESSIONVIEW_PLUGINS names a folder of your own.
• Settings: the install writes none. ~/.sessionkit/view/settings/view.json is made from the shipped template the first time anything reads your settings: sessionview, or a sessionview-config verb such as get (path only prints it). sessionview-config set writes it. SESSIONVIEW_CONFIG names another file instead. ~/.sessionkit/view/settings/neomuttrc is there only if you write it.
• Your tmux server, while it runs: a frame binds keys on the tmux server it attaches to: prefix H (the sidebar as a popup) and three mouse bindings on the status line (MouseDown1Status, MouseDown1StatusRight, MouseDrag1Status). It gives each session it opens the sessionview look, with options set on that session only. With pane_menu on, it also binds a right-click in a pane (MouseDown3Pane), in place of yours, and sets two global @sessionview_agent_menu_ options. Nothing is written to ~/.tmux.conf: these last until that tmux server exits.
• Outside these folders, only on a verb: with fullscreen on, the Dock app on Terminal.app needs the Accessibility permission you grant in System Settings, and macOS keeps it there until you turn it off. Start an agent runs session start, and a message from the menu is sent with message: what those make is in sessiontools' and sessionmail's own lists. The editor tab, when it runs neovim, listens on a socket in $TMPDIR while it runs. With no TMPDIR, the socket goes in XDG_RUNTIME_DIR, or in ~/.local/run, which is made then and stays.

Uninstall

Close every sessionview frame first. Then remove the plugin, if you installed it, and the command. Skip the lines for what you never installed:

claude plugin uninstall sessionview@sessionview
claude plugin marketplace remove sessionview
uv tool uninstall sessionview

Installed from a checkout instead, delete the links it made, and the checkout if you want it gone:

rm ~/.local/bin/sessionview ~/.local/bin/sessionview-* ~/.local/bin/tmux-sidebar

That leaves what the verbs made, listed above. The Dock app, the plugin's cached copy and the state folder are sessionview's alone. To delete them:

rm -rf "${HOME:?}/Applications/SessionView.app"
rm -rf "${HOME:?}/.claude/plugins/cache/sessionview"
rm -rf "${HOME:?}/.local/state/sessionview"

uv's cache stays too, with the other things uv installed; uv cache clean sessionview drops this package's entries. The key bindings go when your tmux server next exits.

The rest is your data: delete it by hand only if you want it gone. ~/.sessionkit/view/ holds your settings, and the kit's other packages keep theirs beside it in ~/.sessionkit/.

Keys and clicks

• sidebar: click a project or seat → go there; right-click, or the ⋯ on the selected project → its menu; + between the lists → a session picker (type to filter, ↑↓, enter); + at the bottom → start an agent; the store name → that store's session and store view, its ⋯ (or s) → Switch store, right-click → Kick; all · grouped on the agents heading are toggles; drag the border to resize; q reloads, Q quits, esc backs out of any view
• tab bar: ◧ at the far left hides/shows the sidebar; click selects, drag reorders, + new tab (the picker); a close ×, on by default; tmux set -g @sessionview_tab_close 0 turns it off
• menu: ↑↓ / j k move, the letter or enter picks, esc or a click anywhere else closes
• agent panes (opt-in): right-click an agent's pane for Speak, Continue, Read Clipboard, Park or Succeed; each mails that agent. Turn it on with sessionview-config set pane_menu true. It replaces your own tmux right-click menu, which is why it is off by default. Using tmux without session view? Add source-file -q /path/to/sessionview/tmux/agent-menu.conf to ~/.tmux.conf and reload.

The look follows herdr's; its colours were matched from herdr's own window.

Configuration

• Settings: JSON, in layers, a later one winning. The template config/config.json holds every key and its default. ~/.sessionkit/view/settings/view.json is yours, made from it on first use; a store's and a project's .sessionview come after it. sessionview-config set KEY VALUE writes yours, and sessionview-config dump --where names the file behind each key. An older install's settings are never read. Moving them is one step, in Upgrading from 0.1.0. Until then sessionview makes nothing and refuses: sessionview-config exits 3 and prints the move to run, and the sidebar shows the same message. If the old file is left beside the new one, it uses the new one and warns you to remove the old one.
• Your neomutt view: ~/.sessionkit/view/settings/neomuttrc, optional, read after the shipped config/neomuttrc.
• Plugins: plugins/<name>/plugin.toml in the checkout.
• Environment: SESSIONVIEW_CONFIG (another file for yours), SESSIONVIEW_FROM (the name mail is sent as, else mail_from, else $USER; sessionview from prints the name in effect), SESSIONVIEW_STATE (state, default ~/.local/state/sessionview), SESSIONVIEW_PLUGINS (another plugin directory).
• sessionview does not read the kit's settings cascade today, only these.

Every file, variable and tmux option is in Configuration, and every key in Settings.

Logs

• ~/.local/state/sessionview/sessionview.log: what went wrong, one entry each, starting with the time (a failed tmux call, an uncaught error with its traceback). Follow it with tail -f ~/.local/state/sessionview/sessionview.log when a click seems to do nothing.
• Levels: log_level in your settings (or $SESSIONVIEW_LOG_LEVEL for one run). error, the default, logs only what went wrong. timing adds a line per click or key with its milliseconds, and each command that took 50 ms or more, so a slow click names its slow part. debug adds every command and every mouse event (what the old sidebar-mouse.log held).
• It sits under $SESSIONVIEW_STATE when that is set. It is not rotated: turn timing or debug on while you look, then back to error.
• Health: sessionview install --check: exit 0 and ready when every requirement is present, exit 1 with each MISSING one named otherwise. It checks the machine, not a running sidebar.