claude-web-ui

A local, zero-dependency browser companion for the Claude Code CLI.

One small Node server (standard library only — no npm install) gives your terminal Claude Code session a browser surface that does the things a terminal can't: render math, hold an isolated side-conversation, answer interactive prompts with a click, and show that Claude is still working.

The terminal session stays the source of truth — the browser is a mirror of it, not a replacement.

Features

• 🪞 Live session mirror (/mirror) — tails your terminal session's transcript (.jsonl) and renders it in the browser with full Markdown + KaTeX (inline $…$ and display $$…$$), which the terminal can't show. Read-only, near-instant, and costs zero extra tokens (it just follows the file). A status bar shows model · effort · context % · rate-limit windows.
• ⌨️ Remote input — type in the browser composer and it is injected into the live terminal session (Korean/IME-safe) via cmux send.
• 💬 btw side conversations — a push-split side panel (button, the btw <question> composer prefix, or ⌘/Ctrl-B) opens an isolated, context-aware side chat. It is seeded with your main conversation's recent context (or a full --fork-session on demand) but never writes to the main transcript. Read-only by default (--permission-mode plan).
• ❓ In-browser question picker — renders Claude Code's AskUserQuestion prompts as clickable cards in the mirror and answers them by sending keystrokes to the terminal. (A pending picker isn't written to the .jsonl until answered, so it is scraped live from the terminal screen.)
• ✻ Working indicator — shows "Claude is working" with the real elapsed time and token count, read from the terminal's live spinner — so you can tell a turn is progressing even during silent thinking, across multi-step turns.
• 💻 Headless chat (/) — a standalone browser chat that drives its own headless claude process (separate from the mirrored terminal session).

How it works

browser  ── SSE /mirror/stream ──◀  server  ◀── tails ~/.claude/projects/<cwd>/<id>.jsonl
browser  ── POST /mirror/send  ──▶  server  ──▶ cmux send / send-key  ──▶ terminal session
                                    server  ──▶ cmux read-screen      ──▶ picker + working spinner

• The mirror follows the session .jsonl incrementally (multi-byte-safe) and streams renderable events over Server-Sent Events.
• Remote input, the question picker, and the working indicator use cmux (send / send-key / read-screen) to drive and read the terminal.
• The status bar reads the JSON that Claude Code feeds its status-line command.
• No database, no framework, no dependencies — just Node built-ins.

Requirements

• Node.js (any recent version — no npm install needed)
• Claude Code CLI (claude on your PATH)
• cmux — for remote input, the question picker, and the working indicator. The read-only math mirror works without it.
• macOS (the cmux integration is macOS-oriented)

Usage

node server.mjs
# then open:
#   http://127.0.0.1:8765/mirror   ← live math-rendered mirror of your terminal session
#   http://127.0.0.1:8765/         ← standalone headless browser chat

Keep it running across sessions (recommended)

node server.mjs dies when the terminal that started it closes — and nohup … & is not enough either: a terminal multiplexer such as cmux tears down its pane's whole process group on session exit, taking the server with it. The included launcher solves this:

./claude-web            # start (and open in a browser)
./claude-web --no-open  # just ensure it's running
./claude-web --restart  # hard-restart (e.g. after editing server.mjs)

On macOS this installs a launchd LaunchAgent (com.claude-web-ui) that owns the server — it survives the terminal/session that started it exiting, auto-starts at login, and is KeepAlive-respawned if it ever dies. The agent definition is generated automatically from the repo's location, so it works wherever you cloned it. Off macOS the launcher falls back to a detached background process. (open-mirror.sh calls this launcher to guarantee the server is up before opening a bound mirror.)

To stop / remove the agent: launchctl bootout gui/$(id -u)/com.claude-web-ui and delete ~/Library/LaunchAgents/com.claude-web-ui.plist.

To bind a mirror to a specific terminal session and cmux surface, pass them in the URL:

/mirror?session=<session-id>&surface=<cmux-surface-id-or-ref>

(open-mirror.sh is an example helper that captures the current terminal's session + surface from cmux identify and opens the mirror bound to them.)

Configuration

All optional, via environment variables:

Variable	Default	Meaning
CLAUDE_WEB_PORT	8765	HTTP port
CLAUDE_WEB_CWD	process.cwd()	working dir whose Claude Code sessions to mirror
CLAUDE_BIN	claude (or Homebrew path)	path to the claude binary
CLAUDE_WEB_MODEL	opus	model for the headless chat
CLAUDE_WEB_PERM	bypassPermissions	permission mode for the headless chat

Notes

• The server binds to 127.0.0.1 only (localhost).
• The headless chat defaults to bypassPermissions for a frictionless experience — set CLAUDE_WEB_PERM (e.g. plan) to tighten it. The btw side sessions are read-only (plan) by default regardless.

License

MIT