zhitongblog/unterm

Unterm

The terminal AI agents can drive.

Cross-platform terminal (macOS / Linux / Windows) built on a customized WezTerm engine, with one design bet: the terminal itself is controllable from the outside by any AI agent over MCP. Claude Code, Cursor, Aider, Continue, your own scripts — they all get the same JSON-RPC surface to spawn shells, run commands, read pane state, capture screenshots, change settings, and record sessions.

The other 2026 terminals each pick a different side: Warp embeds AI inside a closed cloud (Oz), Ghostty stays out of your way and lets you bring your own tools, iTerm2 is Mac-only. Unterm picks the third side — terminal as MCP-controllable surface, deliberately keep AI features out of the terminal, let external agents grip it through the API.

Practical implications:

• Every Unterm window starts a local MCP server (line-delimited JSON-RPC over TCP) and a local HTTP settings server (Web Settings page) on auto-allocated ports. Both are auth-token gated, both are 127.0.0.1-only, no cloud round trip.
• Settings live in the browser, not the terminal. Cell-grid TUIs can't deliver modern form UX (no proper text inputs, no live preview, no color picker). The in-terminal ▼ overlay is intentionally minimal — six quick actions and a link to the Web Settings page.
• 9 languages out of the box: en / 简体中文 / 繁體中文 / 日本語 / 한국어 / Deutsch / Français / Italiano / हिन्दी. Auto-detects from system locale, can be overridden in Web Settings or via unterm-cli lang set <code>.
• Multi-instance discovery: every running Unterm process owns one NATO-named instance (alpha, bravo, charlie…) and writes its ports + auth token to ~/.unterm/instances/<name>.json. Agents that drive several windows at once enumerate that directory.
• Cross-platform parity is a correctness property: if a feature works on Windows but bails on macOS or Linux, that's a bug, not "not supported yet."
• Subtraction over decoration: no AI overlay inside the