Updated July 2026

amux vs Antigravity CLI (agy)

Different layers of the AI engineering stack — and why most teams use both.

Antigravity CLI (agy) is Google's AI coding agent: a single interactive or headless session that writes and edits code using Gemini models. amux is the control plane that runs and manages many such sessions at once — launching them, watching for stalls, auto-recovering failures, and surfacing the whole fleet through a browser dashboard and iOS app. The two tools operate at different layers. You run agy inside amux, not instead of it.

What Is Antigravity CLI?

Antigravity CLI (agy) is Google's successor to the Gemini CLI, released June 18 2026. Where Gemini CLI was open-source (Apache 2.0) with 1,000 free requests per day, Antigravity CLI is closed-source and requires a Google AI Pro subscription. It retains the 1M token context window, the Hooks and Agent Skills system (Extensions were renamed to Plugins), and Subagent support. SWE-bench performance is competitive with Claude Code.

It is a capable, focused tool: one agent, one terminal, one task. For developers already deep in the Google ecosystem — Google Cloud, Vertex AI, Workspace — it integrates naturally. The 1M context window is a genuine advantage for large-repo scans that would otherwise require chunking. The Plugin system enables repeatable, composable agent behaviors.

What Antigravity CLI does not provide is fleet management. It does not watch for a session going silent at 3am and restart it. It does not route tasks across ten parallel agents and surface progress on your phone. That is not its job. That is amux's job.

What Is amux?

amux is an open-source control plane for AI agent teams — run dozens of parallel coding agents from your phone or browser with self-healing, kanban, CRM, and email built in. It is distributed as a single Python file with zero external dependencies, and installs in under a minute. MIT licensed.

At its core, amux wraps any terminal-based AI agent — Claude Code, Antigravity CLI, OpenAI Codex CLI, or any headless subprocess — in a named tmux session, then monitors that session for health. If a session goes silent (context overflow, stuck tool call, network hiccup), amux compacts or restarts it automatically. The dashboard at https://localhost:8822 shows every session's last output and status in real time, from any device.

Beyond session management: amux ships with a built-in kanban board for task routing across sessions, a notes system for shared context, a CRM for contacts, an email API, browser automation, and a scheduler for recurring agent tasks. It is designed to be the single place where a small team runs an AI engineering function.

amux vs Antigravity CLI: At a Glance

They Work Together, Not Against Each Other

The most effective configuration for teams using Antigravity CLI is to let amux manage the fleet. You register your project with amux, set the session runtime to agy, and spawn as many sessions as your workload requires. Each session gets its own tmux window, its own task card on the kanban board, and amux watches for the process going silent. If it does, amux compacts the context or restarts the session — automatically.

The division of responsibility is clean:

• Antigravity CLI (agy) handles the coding: reading files, writing patches, running tests, calling tools via the Plugin system.
• amux handles the orchestration: spawning sessions, routing tasks, recovering failures, surfacing status, and giving you a single dashboard across the whole fleet.

You do not have to choose a model allegiance to use this stack. If one task benefits from Gemini's 1M context window and another fits Claude Code's reasoning profile, amux can run both simultaneously — different sessions, same dashboard, same kanban board.

When to Use Antigravity CLI Alone

Running agy standalone makes sense when you are working on one task interactively and the session lifecycle is short enough that you will be watching it. It is also the natural environment for exploring the Plugin system, testing Subagent behaviors before embedding them in a workflow, or doing a single large-context scan where the 1M token window is the primary advantage you need.

If you are a solo developer on a focused task, already paying for Google AI Pro, and deeply integrated with Gemini tooling — running agy without amux is a reasonable call. amux adds the most value when you need parallel sessions or unattended operation. Below that threshold, it is optional infrastructure.

When to Add amux for Antigravity CLI Fleet Management

The coordination threshold arrives quickly. At two or more concurrent agy sessions, the overhead of watching them manually — tracking which is on which task, noticing when one has stalled, copying context between sessions — exceeds the cost of running amux.

Add amux when:

• You are parallelizing across multiple features, repos, or experiments simultaneously.
• Sessions need to run overnight or unattended — amux will restart a crashed session before you wake up.
• You want to route tasks from a phone or browser without SSH-ing into your machine.
• Multiple people on a team need visibility into what each agent session is working on.
• You want a shared task board that your agy sessions can read from and write to.
• You are mixing runtimes — some sessions running agy, others running claude or codex.

The install is a single command. amux has zero external dependencies beyond Python 3 and tmux, both of which are already present on any development machine running Antigravity CLI. The marginal cost of adding it is effectively zero; the marginal benefit compounds with every additional session.

See also: Agentic Engineering guide and Getting Started with amux.

Migrating from Gemini CLI to Antigravity CLI in amux

If you were running Gemini CLI sessions under amux, migrating is a one-line change. amux session configuration takes a command field specifying what CLI to invoke. Change the value from gemini to agy — the session otherwise behaves identically. Same project directory, same task on the board, same health-check logic.

# Before (Gemini CLI)
amux register myproject --dir ~/Dev/myproject --cmd gemini

# After (Antigravity CLI)
amux register myproject --dir ~/Dev/myproject --cmd agy

The internal rename from Extensions to Plugins does not affect amux — amux only cares about the process lifecycle, not the agent's internal tool system. Hook configurations carry over unchanged. If you relied on any Gemini-specific Plugin behaviors, review the Gemini CLI to Antigravity CLI migration guide for a full diff of the Plugin schema.

One practical note: Antigravity CLI requires an active Google AI Pro subscription, whereas the old Gemini CLI offered a free tier. If you were running many parallel gemini sessions under the free quota, budget accordingly — or consider running those same slots with Claude Code sessions under amux, which has no per-session subscription overhead beyond API token costs.

Frequently Asked Questions

git clone https://github.com/mixpeek/amux && cd amux && ./install.sh

See also: All comparisons · Agentic engineering guide · Getting started with amux · Gemini CLI → Antigravity CLI migration