Expose app-server over network transport for remote/mobile session attach

What feature would you like to see?

The Codex app-server already has an excellent bidirectional JSON-RPC 2.0 protocol with full session lifecycle, approval workflows, and event streaming. The TUI is reportedly being refactored to connect to remote app-server instances. The ask is to ship this: let the app-server listen on a Unix socket or TCP port so that remote clients can attach to running Codex sessions.

Something like:

# Listen on a Unix socket (ideal for SSH — no port forwarding needed)
codex serve --socket /tmp/codex.sock

# Or listen on a TCP port
codex serve --port 3284

# Attach from anywhere
codex attach /tmp/codex.sock
codex attach host:3284

Ideally speaking ACP, since Codex already supports it (via codex-acp) and ACP has broad adoption (Zed, JetBrains, GitHub Copilot CLI, Gemini CLI, Claude Code). Exposing ACP over a network socket would make Codex accessible to any ACP-compatible client — including Toad (2.1K stars) and potential mobile ACP clients — without needing tool-specific adapters.

Why this matters

The community has built 20+ third-party projects to work around the lack of a remote interface for agentic coding tools — mobile apps (Happy Coder, 10.8K stars; Omnara, YC S25; Zane, which already builds on Codex's app-server), Discord/Telegram bridges, web UIs, etc. Every one of them reinvents encrypted relays, session polling, and approval-prompt parsing. They break when the CLI updates because they're scraping terminal output rather than speaking a stable protocol.

Codex is architecturally closer to solving this than any other tool — the app-server already cleanly separates UI from agent logic. The missing piece is just letting it listen on a socket.

Prior art

• OpenCode already ships this: opencode serve / opencode attach http://host:port
• Codex app-server already has the JSON-RPC protocol — it just needs a network listener
• Zane (z-siddiqi/zane) demonstrated the viability by building a web client on top of the app-server's JSON-RPC interface via a Cloudflare Worker relay

Related issues

• #9224 — Codex Remote Control (same motivation, different framing)
• #10816 — Create mobile codex app
• #2744 — Connect from ChatGPT desktop app
• #5780 — Remotely control the local CLI (closed for low engagement — demand has grown significantly since)
• anthropics/claude-code#24365 — Parallel request for Claude Code