@void-energy/webmcp

Agent-callable runtime

Every Void Energy site exposes its runtime affordances to in-browser AI agents via the W3C WebMCP draft (navigator.modelContext). The system tools below register on mount through WebMCPHost.svelte in Layout.astro; consumer-defined tools register alongside via the customTools prop.

Browser support

WebMCP shipped behind a flag in Chrome 146 (Feb 2026). Until other browsers follow, this page detects support and the adapter no-ops cleanly in unsupported browsers — your VE site remains identical for every user; agents that can call navigator.modelContext get the surface for free.

navigator.modelContext

Not detected

no-op fallback

Live engine snapshot

This is the exact payload void_get_state returns to an agent right now. It updates reactively as you change atmosphere / density / open a modal elsewhere.

{
  "atmosphere": "frost",
  "mode": "dark",
  "physics": "glass",
  "density": "standard",
  "scale": 1,
  "openModal": null,
  "shortcutCount": 0,
  "navCount": 5
}

System tool catalog

13 tools register with navigator.modelContext on mount. Two require explicit user confirmation through the existing modal.confirm singleton via agent.requestUserInteraction; the rest trust the browser's native consent layer.

void_get_state

read-only

Snapshot of current atmosphere, mode, physics, density, scale, open modal, auth.

void_list_atmospheres

read-only

Built-in + custom atmospheres available in the registry.

void_set_atmosphere

Switch to a known atmosphere id. Reversible.

void_set_preferences

Update density / scale / fontHeading / fontBody.

void_apply_temporary_theme

Preview a theme without persisting.

void_list_modals

read-only

Modal fragment keys registered on this page.

void_open_modal

Open a modal by key. User can dismiss.

void_close_modal

Close the active modal.

void_toast

Show a transient toast (info / success / error / warning / loading).

void_list_shortcuts

read-only

Registered keyboard shortcuts on this page.

void_fire_shortcut

confirm

Invoke a registered shortcut. Confirmation required.

void_list_pages

read-only

Top-level navigation destinations.

void_navigate

confirm

Navigate to a path. Confirmation required.

Extending with custom tools

Pass a customTools array into <WebMCPHost /> (or compose your own provider) to register consumer-defined tools alongside the VE system set. Tools are spec-compliant ToolDescriptor objects.

import { WebMCPProvider } from '@void-energy/webmcp';

const customTools = [{
  name: 'app_submit_order',
  description: 'Submit the active order',
  inputSchema: {
    type: 'object',
    properties: { confirm: { type: 'boolean' } },
    required: ['confirm'],
    additionalProperties: false,
  },
  execute: async ({ confirm }, agent) => {
    if (!confirm) return { content: [{ type: 'text', text: 'Pass { confirm: true } to submit.' }] };
    const ok = await agent.requestUserInteraction(() =>
      new Promise(resolve => modal.confirm(
        'Submit order?',
        'This will charge your card.',
        { onConfirm: () => resolve(true), onCancel: () => resolve(false) },
      ))
    );
    if (!ok) return { content: [{ type: 'text', text: 'User declined.' }] };
    await submitOrderAPI();
    return { content: [{ type: 'text', text: 'Order submitted.' }] };
  },
}];

<WebMCPHost {customTools} />