CervTerm

CervTerm is an experimental, Windows-first GPU terminal emulator written in Go. It combines a native in-process multiplexer, Lua/Teal configuration, rich font and appearance controls, retained command UX, and a bounded terminal core behind one GLFW/OpenGL frontend.

Two tabs, two independent local panes, and window-local status on the qualified Windows frontend.

Beta software: Windows amd64 is the qualified GUI target. Back up important terminal workflows and keep another terminal available. Renderer selection, remote domains, and live session detach/reattach are intentionally unavailable.

Highlights

• Independent local panes: each pane owns its PTY, parser, terminal state, scrollback, focus, geometry, and zoom. Split, resize, move, swap, and close panes without rebuilding sibling state.
• Visible tabs, native windows, and workspaces: retained tab bar, multiple process-owned windows, named local workspaces, cross-window pane/tab movement, and optional layout-only persistence.
• Terminal behavior: scrollback and reflow, alternate screen, selection, bracketed paste, keyboard/mouse protocols, search, BiDi opt-in, OSC 7 working directory, OSC 8 hyperlinks, OSC 52 policy, semantic shell zones, bells, and notifications.
• Modern configuration: strict v2 documents, includes, environments, profiles, CLI overrides, provenance diagnostics, Lua modules, Teal generation, graph-wide watching, atomic activation, and failed-edit recovery.
• Typed actions and retained UX: leader chords, key tables, exact mouse bindings, command palette, Quick Select, launch menu, tab/window/workspace actions, and Lua callbacks with watchdogs.
• Fonts and appearance: ordered descriptors and fallback rules, ligatures/features, fixed-grid metrics, bitmap/COLR/SVG color glyphs, DirectWrite shaping/raster support, per-side padding, independent opacity controls, layered backgrounds, native blur capability, tab bar, and scrollbar policies.
• Bounded experimental graphics: independent default-off Kitty, Sixel, and iTerm inline-image subsets sharing explicit pane/process budgets and the existing OpenGL renderer.
• Diagnostics and hardening: --doctor, --explain-config, structured logs, panic capture, race coverage, fuzz smoke, replay fixtures, recovery gates, checksums, and GitHub provenance attestations.

Command palette

Search built-in typed actions and labeled user bindings without sending modal input to the shell.

Quick Select

Label visible links and configured matches while preserving pane, viewport, and output identity.

Platform status

Platform	Status
Windows amd64	Qualified beta GUI using GLFW/OpenGL and ConPTY. Release zip available.
Linux amd64	Headless release artifact. A narrow source-built WSLg/X11 GUI integration pass exists, but broad desktop support is not claimed.
macOS	Headless compile evidence only; no packaged or qualified GUI.

See the machine-readable support matrix and Phase 15 platform qualification for exact evidence and exclusions.

Install a Windows beta

1. Download cervterm-<tag>-windows.zip and SHA256SUMS.txt from the latest release.

2. Verify the archive:

   $archive = "cervterm-<tag>-windows.zip"
   $expected = ((Select-String -Path .\SHA256SUMS.txt -Pattern ([regex]::Escape($archive))).Line -split "\s+")[0]
   $actual = (Get-FileHash ".\$archive" -Algorithm SHA256).Hash.ToLowerInvariant()
   if ($actual -ne $expected.ToLowerInvariant()) { throw "SHA256 mismatch" }

3. Extract the zip and inspect the build:

   .\cervterm.exe --version
   .\cervterm.exe --build-info
   .\cervterm.exe --doctor

4. Generate and edit a v2 configuration, then launch:

   .\cervterm.exe --print-default-config > cervterm.lua
   .\cervterm.exe --config .\cervterm.lua

Beta binaries are currently unsigned. Releases include SHA256 checksums and GitHub provenance attestations; winget files are templates rather than a published package, and MSI/WiX publishing is deferred. Read release trust before distribution.

Configuration v2

A compact starting point:

local cervterm = require("cervterm")

return {
  config_version = 2,

  window = {
    initial_rows = 30,
    initial_cols = 100,
    decorations = "system",
    titlebar = "dark",
    padding_left = 8,
    padding_right = 8,
    padding_top = 8,
    padding_bottom = 8,
  },

  font = {
    family = "JetBrainsMono Nerd Font",
    size = 12.0,
    ligatures = true,
  },

  colors = {
    foreground = "#F7F7FB",
    background = "#1E1D40",
    cursor = "#FAD000",
    accent = "#FAD000FF",
  },

  tab_bar = { mode = "multiple", position = "top" },
  scrollbar = { mode = "scrolling", stable_gutter = true },

  keys = {
    { key = "t", mods = "ctrl+shift", label = "New tab",
      action = cervterm.action.NewTab },
    { key = "p", mods = "ctrl+shift", label = "Command palette",
      action = cervterm.action.ActivateCommandPalette },
    { key = "q", mods = "ctrl+shift", label = "Quick Select",
      action = cervterm.action.ActivateQuickSelect },
  },
}

The generated template documents common settings. The public schema also includes composition and persistence fields that are intentionally not expanded inline; consult the detailed configuration references below. V2 can compose local sources with includes, select declared environments and profiles, and apply repeatable typed CLI overrides:

.\cervterm.exe --config .\cervterm.lua `
  --config-override window.background_opacity=0.94
.\cervterm.exe --config .\cervterm.lua --explain-config
.\cervterm.exe --config .\cervterm.lua --explain-config-field font.family

Use --environment <name> or --profile <name> only after declaring that name in the configuration graph; unknown selections fail closed.

CervTerm watches the complete active source graph, including discovered local Lua module dependencies. Reload with Ctrl+Shift+R or term:reload_config(). Invalid edits preserve the active runtime and remain watched for automatic recovery. Application scope is explicit: some fields are live, shell changes apply to new panes, geometry may apply to new windows, and resource changes require restart.

See getting started, configuration compatibility, and scripting/actions.

Default shortcuts

Lua bindings override ordinary built-ins. Active retained modes and reserved search/reload routes run first.

Shortcut	Action
Alt+Shift+= / Alt+Shift+-	Split the focused pane right / below
Alt+Arrow	Focus the nearest pane geometrically
Ctrl+Shift+W	Close the focused pane, or the final window
Ctrl+= / Ctrl+- / Ctrl+0	Zoom only the focused pane / reset zoom
Ctrl+wheel	Zoom only the focused pane
Ctrl+Shift+F	Open scrollback search
Ctrl+Shift+R	Atomically reload configuration
Shift+PageUp/PageDown	Scroll one page
Shift+Home/End	Scroll to history start / live bottom
Ctrl+V or Shift+Insert	Paste clipboard
Ctrl+Insert or Ctrl+Shift+C	Copy selection
Ctrl+Shift+I	Toggle render statistics

Drag a divider with the left mouse button to resize adjacent panes. Tabs, windows, workspaces, command palette, Quick Select, and launch menu are typed actions but do not claim default chords; bind only the ones you want.

Tabs, windows, workspaces, and persistence

The default tab bar mode is multiple, so it appears when a second tab opens. always and hidden are also available. Tabs and panes can move between process-owned native windows while retaining stable process-local identities.

Named workspaces change which local windows are visible; switching does not suspend their sessions. Optional persistence saves bounded layout metadata only. Restore creates fresh local shell processes—it does not preserve or reattach live processes. Remote SSH/WSL domains and live detach/reattach are excluded.

Shell integration and trusted effects

CervTerm recognizes OSC 7 working directories, OSC 8 hyperlinks, OSC 133/633 semantic prompt zones, bounded notification sequences, and bell policies. Detected links require a fresh user click and an allowed HTTP(S) target before the platform opener runs. OSC 52 terminal writes default to off; reads are denied.

Windows native notifications are experimental, consent-gated, and disabled by default. When enabled, terminal-supplied notification titles and bodies are intentionally delivered to the native notification adapter; configuration diagnostics and fallback errors remain value-redacted.

Experimental opt-ins

These features are disabled by default, restart-scoped, and do not carry broad support claims:

Feature	Current boundary
Windows IME/preedit	Experimental native composition path. Broader real Japanese/Chinese/Korean qualification remains incomplete.
Windows UI Automation	Experimental visible-viewport projection only. Narrator/NVDA support is not claimed.
Kitty graphics	Bounded direct-data subset; independent flag and rollback.
Sixel graphics	Narrow 7-bit DCS subset with explicit grammar and budgets.
iTerm inline images	Narrow inline PNG subset; Windows/OpenGL visual evidence exists.

Example graphics opt-in:

return {
  config_version = 2,
  graphics = {
    kitty = { enabled = false },
    sixel = { enabled = false },
    iterm = { enabled = true },
  },
}

Operational rollback is independent: disable the affected protocol and restart. External file/URL transports, animation, broad Sixel scrolling/cursor behavior, and full protocol conformance are excluded.

Known limitations and non-goals

• GLFW/OpenGL is the only GUI renderer; selectable rendering backends are excluded.
• Windows is the only packaged and qualified GUI platform.
• No SSH/WSL domains, tmux integration, or live detach/reattach.
• Layout persistence restores fresh processes rather than live sessions.
• Native blur is capability-dependent and degrades when unsupported or incompatible.
• IME, accessibility, notifications, and inline graphics remain experimental/default-off where noted.
• Broader installed-font, DirectWrite shaping, SVG text, color-font fixture, and interactive vttest qualification continues.

Build and test

Requirements: use the exact Go version declared by go.mod (currently Go 1.25.8). Windows GLFW builds require a working C toolchain. Source-built Linux GUI work additionally requires the distribution equivalents of the GLFW, OpenGL, and X11 development headers. Run maturity gates only from a clean, full-history checkout.

go test ./...
go test -tags glfw ./internal/fontglyph ./internal/frontend/glfwgl ./cmd/cervterm -count=1
go run ./scripts/check-maturity-gates.go
go build -tags glfw -o cervterm.exe ./cmd/cervterm

Package and validate a local beta:

go run ./scripts/package-beta.go -version <tag> -outdir dist
go run ./scripts/release-preflight.go -version <tag> -outdir dist \
  -windows-zip dist/cervterm-<tag>-windows.zip

The Linux release artifact is currently headless:

GOOS=linux GOARCH=amd64 go build -o dist/cervterm-linux-amd64 ./cmd/cervterm

Documentation

• Getting started
• Scripting and typed actions
• Configuration roadmap
• WezTerm parity roadmap
• Support matrix
• Architecture
• Manual verification
• Troubleshooting
• Release packaging
• Release trust
• Support policy

License

See LICENSE.