OverShell 0.2.2

OverShell

Overseer Shell - a Windows terminal shell that wraps the real Windows Terminal rendering engine in your own chrome, tabs and layout - and watches the AI coding agents running in its tabs so you know which one needs you.

The terminal emulation is Microsoft's: VT/ANSI parsing, the text buffer, the GPU-accelerated DirectWrite renderer, selection and scrollback all come from Microsoft.Terminal.Control.dll, built from Windows Terminal's source by our fork and shipped as the OverShell.Terminal.Wpf package - upstream plus a short, documented patch series (a rendering mode that lets the terminal body be translucent). Everything around it - window chrome, tab strip, layout, keybindings, agent detection, notifications - is ours.

It reads your existing Windows Terminal settings.json: profiles, colour schemes and fonts are shared, and there is no second configuration to maintain. OverShell never writes to it.

Install

Windows 10 19041+ (Windows 11 22621+ for the system backdrop), x64 only.

Every release ships SHA256SUMS.txt. Release assets are built by the release workflow, which Authenticode-signs the OverShell binaries with Azure Artifact Signing; the Windows Terminal control binaries arrive signed the same way from our fork, and the ConPTY binaries carry Microsoft's signature. overshell version prints the version and where it runs from.

Build & run

dotnet build OverShell.slnx -c Debug -p:Platform=x64
.\artifacts\bin\OverShell.App\debug_win-x64\OverShell.exe
dotnet test OverShell.slnx -c Debug -p:Platform=x64

Requires the .NET 10 SDK and Windows 10 19041+ (Windows 11 22621+ for the system backdrop). x64 only.

Crashes are always logged to %TEMP%\overshell-crash.log.

To exercise the link handling and shortcuts by hand, run tools\Show-LinkTestCard.ps1 inside a tab: it prints every case with what should happen.

Configuration

Configuration lives in the first of OVERSHELL_CONFIG_DIR, $XDG_CONFIG_HOME\overshell, %APPDATA%\OverShell - so a dotfiles directory that other tools already share through XDG_CONFIG_HOME picks up OverShell too. Machine-local state (labels, the last session) goes to the first of OVERSHELL_STATE_DIR, $XDG_STATE_HOME\overshell, %LOCALAPPDATA%\OverShell.

OverShell settings path    # which directories, chosen by which variable, and every file
OverShell settings init    # a fully commented settings.jsonc + keybindings.jsonc to start from

Or from the window: Ctrl+Shift+P, Change a setting... picks a setting and then its value (theme, accent, backdrop, terminal opacity, what comes back after a restart, notification sinks, the summon key, ...), each with its current value and a line on what it does; Open settings.jsonc opens the file in your editor, written from the commented defaults first. A change from the palette is one line written into the file, the rest of it untouched.

All files are JSONC and reload live when saved: settings.jsonc, keybindings.jsonc, snippets.jsonc, agents\*.jsonc, layouts\*.jsonc, skins\*.xaml. Below, the configuration directory means that root.

Agents

Every tab is watched for the harness running in it - OpenCode, GitHub Copilot CLI, Claude Code, Codex, or any other - and shows what it is doing: working, needs you (a permission or question prompt - never inferred from silence), done (finished while you were not looking; stays until you look), error, exited. Detection uses what the program already emits (title, OSC 9;4 progress, notifications, bell, screen text, the process tree) plus, when installed, the harness's own hooks:

OverShell integrations install opencode   # writes a plugin into OpenCode's plugins folder
OverShell integrations install copilot    # writes hooks into ~/.copilot/hooks
OverShell integrations install claude     # merges hook entries into ~/.claude/settings.json
OverShell integrations install codex      # a notify script + one line in ~/.codex/config.toml
OverShell integrations install shell      # only for profiles that run their own command: a prompt hook in the PowerShell profiles
OverShell integrations status

The OpenCode and Copilot files are separate from your own configuration; Claude Code and Codex keep hooks in their own config files, so OverShell's entries are merged in under a marker and taken out again by uninstall — never replacing anything of yours (a Claude settings.json with comments, or a Codex notify you wrote, is left alone and integrations show <claude|codex> prints the entries to add by hand). All of them do nothing outside OverShell. Inside a tab, OVERSHELL_ENDPOINT, OVERSHELL_TOKEN and OVERSHELL_TAB_ID let any script report state with one curl:

curl.exe -X POST "$env:OVERSHELL_ENDPOINT/v1/report?token=$env:OVERSHELL_TOKEN" `
  -H "Content-Type: application/json" `
  -d "{`"tab`":`"$env:OVERSHELL_TAB_ID`",`"source`":`"me`",`"state`":`"blocked`",`"message`":`"needs a decision`"}"

Rules per harness live in agents\*.jsonc in the configuration directory (bundled defaults inside the app; a file with the same name replaces one wholesale).

Spawning and orchestration. agent.new (herd mode N) opens a tab that starts a harness in a directory with a first prompt, delivered once the agent shows its composer; agent.newWorktree (W) does it in a fresh git worktree beside the repository, so several agents share one repository without touching each other's files. The same is available to programs: a control API on the loopback endpoint (GET /v1/tabs, .../screen, .../wait, POST /v1/tabs to spawn, .../input, .../reply, DELETE) and OverShell mcp, an MCP server over stdio with seven tools (overshell_list_tabs, read_screen, send, reply, spawn, wait, close) - so an agent can oversee the herd itself. "endpoint": { "control": false } turns both off.

Coming back. The herd log (herd mode L) lists everything that happened this run - every state change with its reason, every call for attention - newest first, and keeps it as JSON lines under the state folder's logs\. When an agent's turn ends in a tab you are not looking at, the tab says 2 changed: tab.changes (D) lists the files it changed in its repository since you last looked, with their status; Enter opens one.

Prompt bar, sessions, groups

Ctrl+Shift+Enter opens a prompt bar under the terminal: type once and send to the active tab, to every agent, to the agents that need you, or to every tab (Ctrl+Shift+B opens it aimed at all agents). Snippets in snippets.jsonc — [ { "name": "Explain", "text": "Explain what you just did." } ] — appear on the bar and as Snippet: … commands.

The session - tabs (profile, directory, label, group), view, layout, where every window sits - is saved every two seconds, so a crash or a power cut loses seconds, not the session: the next start brings everything back, says so when the last run was interrupted, and resumes each agent that was running - by session id when the integration reported one (opencode --session <id>, copilot --resume=<id>), else with the tool's "most recent session" form (opencode --continue); a profile whose program is the agent is relaunched with those arguments, a shell gets them typed. Ctrl+Shift+Z reopens the tab you just closed, agent included; session.history lists recently closed tabs and the last ten sessions to bring back - so does the taskbar jump list. After a crash each restored tab shows the last screen it had, dimmed, above its new prompt; two crashes in a minute hold the restore instead of looping; closing with agents working asks first. Workspaces (workspaces\<name>.jsonc, workspace.save) are named sets of tabs to open together. OverShell --fresh starts without restoring. Ctrl+Shift+G puts a tab in a named group (headers in the strip and the list); drag a tab along the strip to reorder it, or use Alt+Shift+←/→. Ctrl+Shift+E opens the explain panel — why a tab is in its state, with the transition history. Ctrl+Shift+X detaches a tab into a window of its own with the same chrome (the terminal moves; nothing restarts) and Ctrl+Shift+A, or that window's close button, brings it back. Ctrl+Shift+F finds in the tab, scrollback included: Enter walks up through older text, Shift+Enter down; the match is the terminal's selection, the others on screen are tinted.

overshell://focus/<tab> is registered for your user at start; a clicked toast (the Palantir recipe sets --launch) opens the running window on that tab. A second OverShell.exe hands its arguments to the first and exits — one window per user. settings.theme is system (follows Windows, live), dark or light, settings.accent the Windows accent, the palette's own or any colour; settings.skin names a skins\<name>.xaml ResourceDictionary that overrides theme brushes, fonts and metrics; colours update live on save.

Views & layouts

Four views, one key each (Ctrl+Shift+1..4, Ctrl+Shift+` toggles the last two), and a switch in the caption bar with a badge for tabs that need you:

A view is a layout plus what the middle shows. Layouts are small JSONC files: where the tabs go (top, bottom, left, right, hidden), how they look (strip, list, rail), whether the sidebar and status bar show. Eight presets ship (top, bottom, left-rail, left-list, right-list, zen, herd, dashboard); drop a same-named file into layouts\ to change one, or pick any preset for the current view from the palette (Layout: …). Retune the views in settings.jsonc:

{ "views": { "terminal": { "layout": "left-list" } } }

Every configuration file — settings.jsonc, keybindings.jsonc, agents\*.jsonc, layouts\*.jsonc — reloads live when saved. Tabs in a git repository show their branch (from .git/HEAD, no process spawned); "git": { "dirty": true } adds a * from git status.

Keys & palette

Ctrl+Shift+P commands · Ctrl+Shift+Space switch tab (fuzzy; @blocked, #repo; with a screen preview) · Ctrl+Shift+J jump to the tab that needs you · Ctrl+Shift+R rename · Ctrl+Shift+1..4 views · Ctrl+Shift+Enter prompt bar · Ctrl+Shift+G group · Ctrl+Shift+E explain · Ctrl+Shift+F find · Ctrl+Shift+T / Ctrl+Shift+W / Ctrl+Shift+D / Alt+1..9 tabs (Windows Terminal's chords; Ctrl+T stays with the shell) · Ctrl+Tab most-recent switcher (hold, tap, release) · Ctrl+Shift+K then a key: herd mode (j/k tabs, b the tab waiting longest, 1-9, l last, s/c a cursor into the sidebar / cards, i the inbox, m/w mute / watch, N/W spawn an agent / on a worktree, L the herd log, D what changed while away, ? the keys) · Win+` summon from anywhere · @3 ... / #group ... / @blocked ... in the prompt bar address it · Alt+Shift+←/→ reorder · Ctrl+Shift+C / Ctrl+Shift+V clipboard (Ctrl+C copies only with a selection). Right-click a tab, a sidebar row or a card for rename / treat as agent or shell / explain / close.

Everything is a command bound in keybindings.jsonc (Windows Terminal's shape; "command": "unbound" removes a default).

Notifications

settings.jsonc names the sinks: an in-window toast for background tabs, a taskbar badge with the number of tabs needing you (amber while one is blocked), a system sound while the window is unfocused, a native Windows toast (toast, no external program; a click opens the tab), and any command - the shipped recipe sends richer toasts through Palantir:

{ "notifications": { "sinks": { "palantir": { "enabled": true } } } }

Status

Working: single terminal on launch, tabs with live titles, profile menu, theming from your colour schemes, custom chrome with a Windows 11 backdrop, links (hover underlines one in its own colour where the renderer would, Ctrl+click opens it), bracketed paste, the agent layer (detection, two-line tabs with state, palette, endpoint, OpenCode plugin, Copilot, Claude Code and Codex hooks, notifications incl. native toasts), the views (layouts, Herd sidebar, Dashboard cards, Zen, live configuration reload, git branch per tab), the depth features (prompt bar and broadcast, session restore with agent resume, overshell:// toast clicks, tab groups and drag reorder, explain panel, skins, tear-off windows), and resilience (two-second session saves, restore after a crash with window placement and tear-offs, agent resume with or without a session id, recently closed tabs and session history, opt-in restart with Windows), and the polish pass (Windows Terminal chords, an honest working directory with a shell hook, restore hold and close question, the previous screen after a crash, workspaces, tab-strip overflow, the jump list, light and dark themes with the Windows accent, tear-offs with the window's chrome, find in the buffer), Terminal parity (the shell integration injected into a plain PowerShell launch, no profile edit; every tab's environment rebuilt from the registry, so a freshly installed tool is on PATH in the next tab), and an extension API (IShell, ITab, IExtension: the shell is the engine, features sit on top) with the keyboard features built on it (herd mode with a which-key bar, MRU Ctrl+Tab, global summon, prompt addressing, a cursor in the sidebar and dashboard, waiting tabs by age), and triage (an inbox of everything waiting for you with y/n and replies that reach the agent through its own API when the integration is installed, Allow / Deny on toasts, mute, watch, auto-advance), and orchestration (spawn an agent in a tab or a fresh worktree with a first prompt; a control API over the endpoint; OverShell mcp so an agent can oversee the herd itself), and oversight (a herd log of every state change as JSON lines with a picker; changes while you were away - the files an agent changed in its repository while you were not looking, counted on the tab and listed).

Not yet confirmed by a human: see the test card (tools\Show-LinkTestCard.ps1) and DESIGN.md 8.

A translucent terminal body, on by default ("window": { "terminalOpacity": 0.85 }; 1.0 for a solid one) - the one thing the control as Microsoft ships it could not do (DESIGN.md 7.6), and the reason the control is now built by our fork (DESIGN.md 12.20).

Documentation

docs/TUTORIAL.md - ten minutes, hands on: the window and the palette, tabs, the look, an agent and what OverShell shows about it, herd mode, the inbox, views, the prompt bar, spawning, leaving and coming back, the control API. In the palette: Help: Tutorial. The first start says so above the first prompt.

docs/GUIDE.md - the user guide: configuration and where it lives, every setting, keys and commands, views and layouts, agents and integrations, notifications, prompt bar, sessions, overshell://, skins, the command line, troubleshooting.

DESIGN.md - what it is, why it is built this way, the architecture decision behind embedding Windows Terminal, the configuration pipeline, field notes on every non-obvious trap encountered, the herd-overseer plan (12), distribution and the release pipeline (13), and the open/closed item list.

Licence

MIT - see LICENSE.