Sinclair vs. other terminals

An honest comparison with kitty, Alacritty, Ghostty, and WezTerm — four excellent terminals, all of which have been at this longer than Sinclair has. If one of them already fits how you work, keep it. This page is for people deciding where Sinclair sits, what it does differently, and what it doesn't do yet. Feature notes on other terminals reflect their documentation at the time of writing; check their sites for the current state.

The factual base for Sinclair's side is parity.md, the feature-by-feature coverage map we keep as we build.

The short version

• kitty is the feature powerhouse with its own protocol extensions (graphics, keyboard) and a scripting ecosystem (kittens).
• Alacritty is deliberately minimal: a very fast emulator that leaves tabs, splits, and everything else to tmux or your window manager.
• Ghostty pairs a fast core with platform-native UI (SwiftUI on macOS, GTK on Linux) and strong defaults.
• WezTerm is the everything-terminal: built-in multiplexing, SSH domains, Lua config, runs everywhere including Windows.
• Sinclair covers the modern-terminal baseline (GPU rendering, tabs/splits, ligatures, themes, live-reload config) and then focuses on something the others don't: being a workspace for coding agents — an agent mesh, a built-in MCP server, per-pane agent status, plus a no-build plugin system and built-in session recording.

Core emulation

All five handle the essentials: truecolor, the common DEC/CSI set, alt screen, scrollback, bracketed paste, mouse reporting, OSC 8 hyperlinks, and OSC 52 clipboard. Differences show up at the edges:

	Sinclair	kitty	Alacritty	Ghostty	WezTerm
GPU rendering	yes (gpui)	yes	yes	yes	yes
Sixel images	yes	no (own protocol)	no	no	yes
Kitty graphics protocol	yes (complete)	yes (origin)	no	yes	yes
Kitty keyboard protocol	yes (all five flags)	yes (origin)	partial	yes	yes
Synchronized output	yes	yes	yes	yes	yes
Shell integration (OSC 133)	yes, auto-injected	yes	no	yes, auto-injected	yes (sourced script)
Reflow on resize	yes	yes	yes	yes	yes

Being specific about the gaps: Sinclair speaks sixel and the whole kitty graphics protocol — every transmission medium, animation, unicode placeholders, cropping, scaling, and z-index — and the whole kitty keyboard protocol, all five enhancement flags over the full functional-key table (see parity.md). The keyboard's one practical limit is the window layer rather than the encoding: gpui reports shift/alt/ctrl/super and caps lock, not hyper, meta, or num lock, and it does not name keypad keys separately on macOS. Stacked combining marks beyond the first per cell are dropped, so complex grapheme clusters aren't fully there yet. Heavy/double/ dashed box-drawing characters fall back to the font instead of being drawn custom.

Workspace

	Sinclair	kitty	Alacritty	Ghostty	WezTerm
Tabs + splits	yes	yes	no (by design)	yes	yes
Command palette	yes	no	no	yes	yes
Scrollback search	yes	yes (pager)	yes	no built-in UI	yes
Copy/vi mode	yes	yes	yes	no	yes
Session restore on launch	yes	startup sessions	no	limited	via plugin
Detach/reattach (live mux)	no	no	no	no	yes
SSH/remote domains	no	ssh kitten	no	no	yes

If you need a terminal that survives its own window closing — a real detachable multiplexer — WezTerm has that built in, and tmux inside any of these does it too. Sinclair restores your tab/split/cwd layout on relaunch (and relaunches agent panes resumed), but it is not a live mux server.

Configuration and extensibility

• Sinclair: a plain key = value file, reloaded live on save, with a GUI settings panel that writes back to the same file. Plugins are plugin.toml manifests — commands, side panels, webview surfaces, event triggers, and MCP tools — with no build step.
• kitty: kitty.conf plus kittens (Python) and remote control — the deepest scripting story of the group.
• Alacritty: a TOML file and intentionally no plugin system.
• Ghostty: a simple config file with strong defaults; extensibility is mostly upstream feature work rather than user plugins.
• WezTerm: full Lua configuration — the config is a program, which is either the best or worst part depending on taste.

What Sinclair does that the others don't

This is the actual reason Sinclair exists, so weigh it by whether you run coding agents at all. If you don't, this section is mostly noise to you.

• MCP server built in. sinclair mcp exposes the running terminal to any Model Context Protocol client: run commands into panes/tabs/splits, read the screen, replay macros, switch tabs, manage git worktrees.
• Relay, an agent mesh. A bundled sidecar that lets independent agent sessions (Claude Code, Codex, others) register on a shared bus, message each other, and park cheaply between tasks — launched into splits and arranged as tiled teams from the terminal.
• Agent-legible UI. Every pane self-reports a state (working, blocked, done, idle) shown on its tab and rolled up in an activity panel; tabs show git branch + cwd; OSC 9/777/99 raise native notifications and light up background tabs.
• Git worktrees as first-class verbs. Create/open/remove worktrees as keybinds or MCP calls, one isolated branch per agent, with lifecycle triggers for setup/teardown.
• Recording + export in the box. Record any pane to an asciinema v2 .cast, then export GIF/MP4/WebM — on macOS through the app's own text renderer, so exports match what you saw on screen.
• Typed-command macros. Record the commands you type, replay them paced by shell-integration prompt marks; stored as plain text files.

Parts of this exist elsewhere in other forms — kitty's remote control and WezTerm's Lua can script panes, and anything can run agents in plain shells. The difference is that Sinclair treats "a grid of agents plus the human supervising them" as the primary workload rather than something you wire up yourself.

What Sinclair doesn't do (yet)

Straight from parity.md and the roadmap:

• No detachable sessions / live multiplexing, no SSH domains.
• Grapheme clusters beyond one combining mark per cell.
• Heavy/double/dashed/rounded box-drawing falls back to the font.
• No macOS status-bar (tray) item.
• macOS and Linux are the primary targets; Windows packages are published with each release but get far less testing.
• It's young. kitty, Alacritty, and WezTerm have a decade-plus of combined edge-case fixes that Sinclair simply hasn't accumulated yet. If you hit one of those edges, file an issue.

Choosing

• You want maximum protocol features and scriptability: kitty.
• You want the smallest, most focused emulator and you already live in tmux/i3: Alacritty.
• You want the most platform-native feel with great defaults: Ghostty.
• You want built-in multiplexing, SSH domains, Lua, or Windows: WezTerm.
• You spend your day supervising coding agents, or you want the tabs-splits-themes baseline plus MCP/plugins/recording without extra tooling: Sinclair.