@supermux/core is a TypeScript library for building apps on top of Claude Code, Codex, Cursor, OpenCode, Grok Build and Antigravity. It runs each agent's own CLI on your machine with the login that CLI already has, so what you build runs on your own subscriptions. Nothing is proxied. Your code gets one API for sessions, one normalized event stream, permission prompts and questions as events, subagents, and your TypeScript functions as tools. Each agent runs behind a small keeper process, so your app can crash, restart or redeploy and pick a running turn back up. The package includes an agent skill, so you can also ask your agent to build the app: npx skills add UstaLabs/supermux --skill supermux-core Two examples to copy: a chat app in the style of T3 Code, and a kanban board where each card is a task run by one agent in its own git worktree. MIT. Linux and macOS (Windows through WSL). It's 0.1, so the API can still change. It's the same core the supermux app runs on.

Supermux Core

Build Agentic Apps on your Claude Code, Codex Subscription

Build Agentic Apps on your Claude Code, Codex Subscription