What gamestruct is

gamestruct is a zero-dependency ESM library. It defines one contract - four primitives over one semantic tree - and ships reference renderings for both audiences plus two transport bindings.

The four primitives

Every door exposes exactly these four operations. A client that uses only these four can operate the surface.

primitive	signature	meaning
`observe`	`() -> Snapshot`	the surface’s state for this seat
`act`	`(handle, verb?, value?) -> Result`	do one thing, by stable handle
`wait_for`	`(predicate, timeoutMs) -> Outcome`	resolve when a condition holds, or time out honestly
`events`	`(sinceFrame) -> { frame, events[] }`	what changed while you were not looking

The two lanes

Both lanes read the same tree. They are not two implementations of the same feature; they are two renderings of one description.

human lane (profiles/human) - render, a11yDump, audit. The assistive-technology view: roles, accessible names, focus order, live regions.
agent lane (profiles/agent) - toolCatalog, affordances, toolCall. The machine view: one MCP-shaped tool per actionable node, each with an inputSchema so a client auto-wires.

The bindings

A binding is transport only; it never invents state.

HTTP (bindings/http) - /observe, /act, /wait_for, /events, /health. Fail-closed token auth.
MCP (bindings/mcp) - JSON-RPC 2.0: initialize, tools/list, tools/call, plus observe/events as direct methods.

What ships in the box

file	what it carries
`lib/roles.mjs`	the ARIA-aligned role + action vocabulary
`lib/tree.mjs`	the semantic tree, stable handles, traversal, lookup
`lib/events.mjs`	the bounded event ring with an honest cursor
`lib/bridge.mjs`	the door: tree + ring + handlers, the four primitives
`lib/profiles/human.mjs`	the human lane (render, a11yDump, audit)
`lib/profiles/agent.mjs`	the agent lane (toolCatalog, affordances, toolCall)
`lib/bindings/http.mjs`	the HTTP door
`lib/bindings/mcp.mjs`	the MCP door
`lib/adapters/synmergia.mjs`	the reference WORLD adapter
`lib/adapters/vant.mjs`	the reference BRAIN adapter
`bin/gamestruct.mjs`	the CLI: `check` and `doctor`

The smallest surface

A door and a client share exactly one vocabulary: the handle. Everything else is a rendering.

import { Bridge, ROLES, human, agent } from 'gamestruct'

const bridge = new Bridge({ name: 'pause menu' })
bridge.tree.add(null, { id: 'ui:start', role: ROLES.BUTTON, name: 'Start game' })
bridge.on('ui:start', { activate: () => startGame() })

That is the whole product: the rest is the two lanes reading it.

More in these docs: start here · the contract · bindings · adapters · the CLI