@ethisyscore/extension-runtime

Host + plugin runtime for EthisysCore extension contracts:

• Contract A — host-rendered SDUI extensions. Plugins return a closed-vocabulary SduiNode tree from a ResourceHandler; the host's declarative interpreter mounts it directly.
• Contract B — worker remote-runtime extensions. Plugin code runs in a sandboxed Web Worker; UI mutations flow via Remote DOM into the host's semantic primitive registry. The capability token never crosses the worker boundary.

Built on top of @ethisyscore/protocol (canonical bridge / manifest / SDUI / capability / theme types).

Subpath exports

| Entry | Use | Surface | | ----- | --- | ------- | | @ethisyscore/extension-runtime | Root re-exports | Stable consumer-facing types and helpers. | | @ethisyscore/extension-runtime/host | Host integration | WorkerRemoteDomTransport, declarative interpreter, semantic component registry, offscreen-canvas helpers. | | @ethisyscore/extension-runtime/plugin | Plugin side | ExtensionRuntimeProvider, useMcpResource, useMcpTool, transport abstraction. | | @ethisyscore/extension-runtime/mock-host | Local dev | DeclarativeMockHost and the mock-host CLI entry. |

The mock-host bin (npx mock-host <dir>) is shipped — boots a Vite dev page that mounts the declarative interpreter against a directory of SDUI JSON resources. Run --render-mode remote-runtime <bundle> for the Contract B variant.

Local development

This package consumes @ethisyscore/protocol via npm link. The protocol package is registered globally in E1.S8:

cd <repo>/sdk/extension-runtime
npm install
npm link @ethisyscore/protocol

Scripts

| Script | Purpose | | ---------------- | ---------------------------------- | | npm run build | Build ESM + CJS + .d.ts via tsup | | npm test | Run unit tests (Vitest, jsdom) | | npm run lint | Type-check only (tsc --noEmit) |

Targets

• Node.js >= 20
• React >= 18 (peer dep, required by ./host and ./plugin subpaths in later tasks)