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What is an agent CLI harness?

Name: ConnectOnion
Author: ConnectOnion

An agent CLI harness is a set of command-line tools an AI agent runs to reach email, chat apps, a browser, files and servers. How it works, and what ConnectOnion includes.

An agent CLI harness is a set of command-line tools that an AI agent runs to reach real services: email, chat apps, a browser, files and servers. Each capability is an ordinary shell command, so any agent that can run a shell can use it, including Claude Code, Codex and agents you build yourself. A person can run the same command to see exactly what the agent sees. ConnectOnion is an open-source agent CLI harness, and its commands all start with co.

1. Install the harness

ConnectOnion is a Python package (3.10 or newer) that installs the co command.

pip install connectonion

2. Give the agent an identity

co init creates a keypair and a 0x address, signs in to OpenOnion with $5 of model credit, and gives the agent a mailbox.

co init

3. Connect the services it needs

Each service is one command: co auth google for Gmail, Calendar and Drive, co auth microsoft for Outlook, co whatsapp listen for WhatsApp, co browser for a real browser.

co auth google
co gmail inbox
co browser go_to https://example.com

4. Hand it to your coding agent

co skills link links ConnectOnion's bundled skills into Claude Code and Codex, so they know which co command to run.

co skills link

5. See everything it can do

co commands prints every command and subcommand with a one-line summary. There are 42 top-level commands.

co commands

FAQ

Why commands instead of an SDK?

A command works with any agent that has a shell, not only agents written in one language. Its output is text you can read, pipe and log, and you can run it yourself to check what the agent did. ConnectOnion also ships a Python SDK for building your own agent, and the SDK exposes the same capabilities as tools.

Which agents can use an agent CLI harness?

Any agent that can run shell commands: Claude Code, Codex, Cursor and similar coding agents, ConnectOnion's own co ai, or a script. co skills link adds ConnectOnion's skills to Claude Code and Codex.

What does the ConnectOnion harness connect to?

Gmail, Google Calendar, Meet, Drive and YouTube; Outlook mail, contacts, calendar and Teams meetings; WhatsApp, Telegram, Discord, Feishu, Lark and SMS; a real logged-in browser; a Synology NAS; remote agents; and servers you own. It also gives the agent its own address, mailbox and memory.