iii

iii is a language-agnostic runtime where services, agents, and tools are composed of the same things: workers, triggers, and functions. One engine process (default port 49134) holds a live registry of every connected worker, every function those workers expose, and every trigger bound to them. Workers are independent OS processes that open a WebSocket to the engine and register Functions (service::name handlers) and Triggers (the events that invoke those Functions). There is no direct worker-to-worker traffic, every call routes through the engine, which makes the language, runtime, and physical location of any worker invisible to its callers.

When to Use

Use this skill to discover live iii capabilities, call functions, author SDK workers, bind trigger types, or operate project workers through Compose.

You extend yourself by writing iii workers. A few lines get you on the bus:

import { registerWorker } from 'iii-sdk'

const iii = registerWorker(process.env.III_ENGINE_URL!, { workerName: 'demo' })

iii.registerFunction('demo::add', async (payload: { a: number; b: number }) => {
  return { c: payload.a + payload.b }
})

The instant the handshake completes, demo::add is callable from any worker (and the harness itself) via iii.trigger({ function_id: 'demo::add', payload: { a: 2, b: 3 } }). No restart, no registration with the harness, the engine routes it automatically.

The four primitives

Primitive	What it is	Owned by
Engine	One coordinator process. Routes every invocation.	The operator
Worker	A process that opens a WebSocket to the engine.	Anyone who writes one
Function	A named handler inside a worker, id service::name. Stable across worker restarts.	The registering worker
Trigger	A (type, config, function_id) triple. Causes a function to run when an event fires.	A worker (the type-publisher) + a caller (the binding)

Three consequences worth internalising: