Arc Work

I'm building this because I’m not convinced we know what the end-game UI for agentic development looks like yet.

I actively use Claude Code, Codex, and Cursor CLI. I feel like using them together gets a better (and cheaper) result, but I was finding it impossible to stay on track while juggling terminal panes and a sprawl of Markdown. Particularly while working on more than one project at a time.

Arc Work is my exploration of a unified development environment, where conversations, tasks, diffs, and multiple harnesses, are part of the same application and workflows.

It’s built primarily for myself, but I’m putting it out into the world to see if it resonates.

Status: early, macOS-only, distributed source-only — run it with pnpm dev (see below). No packaged build yet.

Requirements

• Node.js 22 or newer
• pnpm 10.24 or newer
• macOS for the current Electron development target

Development

pnpm install
pnpm dev

Useful commands:

pnpm typecheck
pnpm test
pnpm build
pnpm storybook

Launching a live session needs node-pty and better-sqlite3 compiled for Electron's ABI. pnpm install builds them; if a native-module ABI error appears on launch, rebuild them explicitly:

pnpm rebuild   # electron-rebuild -f -w node-pty,better-sqlite3

Project Layout

src/main/       Electron main process, storage, hooks, MCP, and services
src/preload/    Electron preload bridge
src/renderer/   React renderer
src/shared/     shared schemas and types
tests/          Vitest coverage

Runtime state is local-only and ignored by git.

Hook instrumentation

To observe a target CLI (Claude, Codex, Cursor), Arc Work installs a single Arc-owned helper at ~/.arcwork/<profile>/runtime/arc-hook-signal.mjs — outside any repo, one copy per profile — and merges hook config pointing at it into the provider's settings (.claude/settings.local.json, .codex/hooks.json, .cursor/hooks.json). The helper no longer lands in the workspace, so it can never show up in git status. Each Arc-launched shell carries ARC_HOOK_HELPER (the helper's absolute path) next to ARC_HOOK_SOCK. One known limitation:

• Not portable. The merged hook commands are absolute (the Arc-owned helper path, plus node from the runner's PATH), so they only fire under Arc Work — instrumentation does not travel with the repo, by design. Re-running an install replaces Arc's prior hook block (matched by the helper filename) rather than appending, so a moved or upgraded helper leaves no orphaned stack behind.

The MCP server Arc exposes to those CLIs is wired repo-clean too: Claude and Codex receive it inline on the launch command (--mcp-config, -c), writing nothing. Cursor (which has no inline lever) instead loads an Arc-owned plugin via --plugin-dir — one directory under ~/.arcwork/<profile>/runtime/ that bundles both its hooks and the arc MCP server (mcp.json), so nothing lands in the workspace or in ~/.cursor. The explicit arc-mcp <provider> --write command still drops a persistent repo/user config if you want one.

The provider hook settings (.claude/, .codex/, .cursor/) are still merged into the repo today; relocating those out of the workspace (so a repo Arc opens stays byte-for-byte clean) is tracked separately.

Contributing

Bug reports and small focused fixes are welcome. See CONTRIBUTING.md for setup and the checks CI runs, and SECURITY.md to report vulnerabilities privately.

Profiles: dev vs stable state

pnpm dev and the built/preview app keep separate durable state, so a dev rebuild, half-run migration, or crash can never touch the database or Chromium profile of the app you rely on daily. State is split two ways (resolved by src/main/db/paths.ts; src/main/index.ts pins app.setPath("userData", …) at boot):

• Domain DB — home-rooted under ~/.arcwork/<profile>/, easy to inspect, back up, and reset from CLI/MCP workflows.
• Electron profile (cache, cookies, GPUCache, partitions, window state) — per-profile under one Arc Work userData app dir.

Profile	Selected by	DB file	Electron userData
stable	pnpm start (preview), or default	~/.arcwork/stable/state/arc.sqlite	~/Library/Application Support/Arc Work/stable
dev	pnpm dev (ARC_PROFILE=dev)	~/.arcwork/dev/state/arc.sqlite	~/Library/Application Support/Arc Work/dev

• ARC_PROFILE=dev|stable forces the profile; otherwise the presence of ELECTRON_RENDERER_URL (set only by electron-vite dev) means dev.
• ARC_DB_PATH=/path/to.sqlite overrides the DB file outright (scratch/testing); the Chromium profile still follows ARC_PROFILE.
• The resolved profile + DB path are logged at startup ([arc] profile=… db=…).
• Migration is manual: there's no automatic move of pre-existing files. To carry over old state, copy your DB to the new path by hand once.