amux vs OpenAI Symphony
Developer-driven Claude Code fleet vs autonomous Codex pipeline — same goal, fundamentally different execution model.
OpenAI Symphony (open-sourced June 2026) is a ticket-driven autonomous coding pipeline. It polls a Linear issue board, claims tickets, spawns Codex CLI agents in parallel, and opens GitHub pull requests — no human input required during execution. Written in Elixir/OTP, MIT licensed. Designed as a reference implementation for autonomous coding at OpenAI's internal scale.
amux is an open-source control plane for running a parallel AI engineering team. It runs Claude Code sessions in tmux, monitored from a web dashboard or mobile app, with a built-in kanban board, self-healing watchdog, and REST API for agent coordination. MIT + Commons Clause, single Python file, zero external dependencies.
For the deep-dive comparison including architecture breakdown, workflow analysis, fault tolerance details, and the "500% PR increase" claim, see the complete amux vs Symphony comparison.
The core difference: autonomous pipeline vs developer cockpit
Symphony's design is fully autonomous: connect it to Linear and Codex, and it runs indefinitely without human intervention. Tasks flow from issue to PR with no dashboard to monitor and no controls to steer mid-run. This is powerful for teams with well-defined, tightly scoped tickets and a high degree of trust in Codex's output.
amux gives you a cockpit. You see every session, its current status, token spend, and live output. You can steer a running agent, replay a failed session, or pause the board. The self-healing watchdog handles failures automatically, but you're always able to intervene. This works better for codebases where human judgment is still part of the loop — most production systems.
Feature comparison
| Feature | amux | OpenAI Symphony |
|---|---|---|
| Agent model | Claude Code (Anthropic) | Codex CLI (OpenAI) |
| Execution model | Developer-driven dashboard + queue | Fully autonomous pipeline |
| Issue tracker | Built-in SQLite kanban board | Linear (only, at launch) |
| Web dashboard | Full UI — sessions, board, peek, spend | None in reference implementation |
| Mobile management | Native iOS app + PWA | None |
| Self-healing | Python watchdog — context overflow, crash, stuck, rate-limit | Elixir/OTP supervision trees |
| Fault tolerance | Auto-compact, restart with message replay, YOLO mode | Process supervision + exponential backoff |
| Runtime | Python 3 + tmux | Elixir/OTP (BEAM VM) |
| Setup complexity | Low — ./install.sh, 5 min | High — Elixir, mise, Linear + Codex API keys |
| Human-in-the-loop | Optional (YOLO mode for full autonomy) | Not in reference implementation |
| License | MIT + Commons Clause | MIT |
| Maintenance | Active — iOS app, cloud deploy, regular commits | Reference implementation, not a maintained product |
When Symphony is a better fit
- You use Linear for issue tracking. Symphony's Linear integration is native and purpose-built. If your team lives in Linear, the issue-to-PR automation is compelling.
- You prefer Codex. If you've chosen OpenAI's Codex as your primary coding agent, Symphony is the orchestrator built for it.
- Fully autonomous pipeline. If you want the pipeline to run with zero human touchpoints — tickets in, PRs out — Symphony's design makes that the default.
- You have Elixir expertise. Symphony's OTP architecture is sophisticated and extensible for teams already in that ecosystem.
When amux is a better fit
- You prefer Claude Code. amux is built specifically for Claude Code and its output patterns. Self-healing handles Claude-specific failure modes (context exhaustion, thinking-block corruption) that Codex doesn't have.
- You want observability. The dashboard, mobile app, per-session token spend, and live peek give you visibility that Symphony's reference implementation doesn't provide.
- You don't use Linear. amux's built-in SQLite kanban requires no external services.
- Quick setup. Python 3 + tmux + one script. Symphony requires Elixir and mise, which most developers don't have installed.
- Long-term maintenance. OpenAI has said Symphony is a reference implementation, not a product they plan to maintain. amux is actively developed with a public roadmap and iOS app.
See also
- Full amux vs Symphony deep-dive — architecture, workflows, fault tolerance in detail
- Getting started with amux
- Kanban board guide
- amux vs OpenAI Codex
- amux vs Claude Managed Agents
Get started with amux
Run an AI engineering team from your dashboard or phone. Open source, Python 3 + tmux.
git clone https://github.com/mixpeek/amux && cd amux && ./install.sh
amux register myproject --dir ~/Dev/myproject --yolo
amux start myproject
amux serve # → https://localhost:8822