nebula

English

✨ About

Nebula is a terminal emulator for Windows, built in Rust on a GPU-accelerated rendering core and designed around one idea: your terminal sessions are too valuable to die with a window. It pairs a tmux-style resident session model with a glass UI, an AI-CLI-aware sidebar, and a shell experience that works without extra setup.

🚀 Features

Sessions that survive

• Session residency — closing the window detaches instead of killing: every PTY (your running claude, builds, SSH sessions) keeps running in a resident process. Launch Nebula again and the window re-attaches — same processes, same scrollback, mid-conversation.
• Cold session restore — if the resident process is gone (reboot, crash), the next launch still restores your tab layout and per-tab working directories from a continuously autosaved snapshot, with a crash-loop breaker.
• Single instance — a second launch hands over to the running instance instead of piling up windows.

Built for AI-CLI workflows

• Real brand marks in the sidebar — a tab running claude shows the actual Anthropic starburst; codex shows the OpenAI blossom, tinted to the theme. Other programs get Nerd Font icons (gemini, copilot, git, vim, cargo, …).
• Live turn state, wired to the source — Nebula installs Claude Code hooks (and Codex notify) pointing at a bundled bridge (nebula-hook.exe, dependency-free): prompt submitted → spinner; turn finished → dot + toast; Claude needs your input → toast carrying the actual message text. Delivered over a local named pipe, with no shell integration required.
• Click-to-focus notifications — every toast knows which pane raised it: click one and Nebula comes to the foreground, switches to that tab and focuses that split.
• Zero setup, self-healing — the hook entries install on first boot and re-install themselves if a config switcher rewrites the file (a watcher on the config directory re-applies them). Scoped by environment: claude running in any other terminal is untouched. nebula setup-ai --remove undoes everything.
• Plays nice with existing notifiers — codex has a single notify slot; Nebula wraps it (--chain) instead of stealing it, so a pre-existing notifier keeps firing.
• Fallback signals — OSC 133 command tracking + BEL still cover every other CLI: long builds toast on completion, with their duration.
• Native SSH sessions — saved hosts open directly through Nebula's Rust SSH transport: no wrapper shell and no external console window. Host aliases, usernames, ports and identity files are resolved from ~/.ssh/config; authentication supports standard private keys and certificates, encrypted-key passphrases, Windows Credential Manager passwords, and keyboard-interactive/MFA. Accepted host keys use the standard known_hosts store, and additional tabs reuse an already authenticated connection to the same user@host:port for a faster second shell.
• Built-in SFTP transfers — open a remote file drawer from any saved SSH host and reuse its authenticated connection. Browse or type remote paths, filter entries, upload and download files or folders, create and rename folders, recursively delete, follow symlink targets, and cancel transfers with visible progress and errors.
• AI-aware over SSH — remote Hook envelopes can return through a per-channel, randomly authenticated private OSC bridge. Nebula validates the channel token, replaces any remote pane identifier with the local pane, and routes the event through the existing sidebar and Windows notification path. The nebula ssh compatibility command remains available for forwarding, query and explicit-command forms that need the system SSH client.

Performance & correctness

• Instrumented startup — the boot path is fully traceable (NEBULA_BOOT_TRACE=1); no shell profile is loaded and history loads lazily.
• Modern ConPTY host — ships the side-by-side ConPTY host for correct resize behavior, with its startup handshake (DA1) pre-primed so a new tab doesn't stall on that round-trip.
• Coalesced resizing — interactive drags resize the grid only; the PTY learns its final size once, so full-screen TUIs don't smear redraws into scrollback.

Shell experience

• Inline ghost-text completions — fish-style dim suggestions from command history and filesystem paths; accept with → or Tab.
• Persistent indexed history — commands stored as JSONL under %APPDATA%\Nebula, shared across sessions, with prefix hints.
• Powerline prompt built in — themed gradient prompt with git branch and clock, for PowerShell and Git Bash, no plugins to install.
• Quality-of-life fixes — unquoted cd D:/Program Files just works, bare $env:KEY=value assignments are auto-quoted, ls gets colors and clickable OSC 8 hyperlinks.

Documents & native mathematics

• Markdown/GFM document tabs — open Markdown, JSON, and plain-text files directly from the file drawer with headings, lists, tables, code blocks, links, quotes, word wrapping, and virtualized scrolling.
• Native TeX mathematics — inline $...$ and display $$...$$ formulas are parsed and laid out entirely in Rust, then drawn through cached Latin Modern Math glyphs and GPU rule quads. Fractions, radicals, scripts, limits, integrals, matrices, scalable delimiters, Greek letters, and common symbols render without a WebView, JavaScript runtime, or external TeX process.
• Bounded document rendering — oversized formulas fit the reading column, long prose and failed formulas wrap, and parser, layout, cache, atlas, and per-frame work all have explicit limits. See the math rendering fixture for the screenshot and regression set.

Interface

• Glass chrome & seven themes — Nebula plus three matched light/dark pairs: Silver Light / Steel Dark, Limestone / Coal Dark, Linen Light / Moss Dark. One skin system drives chrome, prompt and dialogs; every theme persists across restarts.
• Tabs & splits — sidebar tabs with drag-to-reorder and drag-to-dock into splits; unfocused panes dim instead of growing borders.
• Files, Git and SFTP drawers — browse local or remote files without leaving the terminal. The Git drawer can stage, commit, pull fast-forward updates, and push.
• Quick terminal — global Ctrl+` drops a Quake-style terminal from the top edge.
• Settings tab & command palette — settings opens as a normal reusable tab, with themes, language, background image/opacity, shell choice and completion behavior; all persisted.
• Inline images — OSC 1337 image protocol support, lazily anchored to scrollback rows.

📥 Install

⚠️ Install the bundled font first. Nebula's powerline prompt, program icons and AI brand marks are drawn with Maple Mono Normal NF CN (a Nerd Font). Nebula embeds the same font as a runtime fallback so forgetting to install it no longer breaks the interface, but a normal system installation is still the intended setup. The font ships in the release zip under fonts/ and the repo at assets/fonts/MapleMonoNormal-NF-CN-Regular.ttf — double-click it and press Install, then launch Nebula. Nebula checks the font on every launch; if the system font is missing, a dismissible reminder can open the bundled `