The command line

rxr is Reactor from a terminal. You write a loop in a file, save it as a draft, try it, test it, publish it and run it, with no page open. An AI agent that works in a terminal can do the same: every command has an output made for a program.

rxr works in your account as you, and only as far as your role allows. It reaches plutonium.io through the same server an AI tool connects to (Connect an AI tool), so the two can do the same things.

Install

curl -fsSL https://plutonium.io/install.sh | sh

This puts one file, rxr, in ~/.local/bin. It runs on macOS and Linux, on arm64 and x86-64, and it needs nothing else installed. The installer checks the download against a SHA-256 it carries, and installs nothing when they differ. Set RXR_INSTALL_DIR to install somewhere else.

Sign in

rxr login

rxr opens plutonium.io in your browser. Sign in, and a page asks whether to connect rxr, with what it could do. Press Allow, and the terminal says it is connected. You paste no key.

When the terminal is on another machine than your browser, run rxr login --no-browser: open the address it prints, press Allow, and paste the address the browser ends on.

Settings lists the connection under Connected AI tools, as “rxr on” and the machine’s name. Disconnect there ends it at once. rxr logout forgets the sign-in on one machine.

Your first loop

rxr new support_desk
rxr push support_desk.loop.yml
rxr run support_desk "Where is my order?" --draft
rxr publish support_desk
rxr run support_desk "Where is my order?"

1. rxr new writes support_desk.loop.yml, a small loop that saves as it is. Open the file and change its name, its description and its entry, the instruction the loop follows. Building a Loop explains every key.
2. rxr push saves the file as the loop’s draft. A draft serves nobody. When the document has a problem, the answer names each one and where it is.
3. rxr run --draft runs the draft as you, and prints what the run does and then its reply. Change the file, push, and run again until it does what you want.
4. rxr publish makes the draft the version that runs use. It asks you first.

rxr chat support_desk --draft is a conversation: each line you type is your next message. With no command at all, rxr lists your loops to choose from.

To change a loop you have, rxr pull support_desk writes its document to a file, and says which version number the changed copy must carry.

Test cases

A loop document can declare test cases: example conversations that must pass before a version publishes (Testing a Loop).

rxr test support_desk

This runs each case against the draft and prints a verdict for each, with the reason when one fails. Each case is a run that costs money, so rxr asks before it starts them. A case run acts on nothing live.

Runs

When a run waits for your approval, rxr shows what it asks and waits for your answer. A run costs what any run costs, wherever it was started.

For an AI agent

An agent that drives rxr reads rxr guide: the whole of this page for a program, with the order of the commands and what each exit status means.

• --json on any command prints one JSON document on standard output, and nothing else.
• No question is asked when there is no terminal. A step that publishes, or that spends money on test cases, then needs --yes: the agent asks you, and passes it when you agree.
• The exit status says what happened, so a program need not read sentences:

An AI tool that speaks MCP needs no rxr: it connects to the same server. rxr mcp prints the lines that add it to Claude Code, Cursor or another tool.