Introduction

cyberlegion lets one agent session reach another. Send a peer a message, spawn one to take a piece of work off your hands, collect the verdict when it comes back. Sessions in Claude Code, Cursor, and Codex all join the same Legion and address each other the same way, so a mixed set of tools behaves like one team.

There is nothing to run. No server, no port, no daemon to keep alive. State lives under a shared hub root ($CYBERLEGION_ROOT, else the global hub), and each harness’s own session-start hook delivers the mail.

The Legate

The Legate is the agent plugin, and it is the part you talk to. Ask in plain language: get this to the pane on the right, spawn a reviewer for this branch, tell me what is in my inbox. It reads the request and works out how to reach the target, choosing between a warm peer in its own pane, a cold one-shot subagent, and simply doing the work in-session.

That choice is the whole value of the layer. Load the legate skill in any session and you have it, along with onboarding and inbox skills for the rest. See Skills.

The CLI

cyberlegion is the npm package the Legate composes, and you can drive it yourself. It spawns sessions, sends and reads mail, and reports which multiplexer is live. It never decides when any of that is the right move, which is exactly why a routing layer can be built on top of it.

Reach for it directly when you already know the command you want, or when you are scripting. Its output is shaped for agents to read: token-efficient TOON by default, --format json when something needs to parse it. See the CLI Reference.

Building your own layer

The Legate is one routing layer over the CLI, not the only one. cyberfleet is another: its skills call unit spawn, unit who, and mail send directly and use no cyberlegion skill at all, because fleet work needs its own judgment about mission graphs and merge order. SDD builds on the same primitives.

That is what the CLI holding no routing opinion buys. A layer takes the parts it needs and decides the rest for itself.

Where to go next

• Installation: the plugin via the marketplace, the CLI via npx
• The Spine: the three nouns every command is named after
• Architecture: how the layers fit and the invariants that hold them