Status: Stable · RFC 0008.
Normative home:
nodePackRuntimes.
Why this exists
v2 carried this family only by pointing at spec/v1/node-packs.md. This is its v2 contract, and it lets a remote pack name its MCP server by an inline MCP Registry record instead of a bare URL. The shape is $defs/Runtime in schemas/v2/node-pack-manifest.schema.json.
Languages
runtime.language is one of javascript, python, go, wasm, wasm-component, remote. entry is a path inside the tarball, or, for remote, the URL of an MCP server the host calls as an MCP client. A host MAY refuse a language it cannot execute, at workflow registration and with unsupported_runtime.
WASM
A host that loads wasm packs MUST advertise nodePackRuntimes.wasm with at least one abiVersions[] entry (RFC 0008), and MUST reject at load a pack whose openwop_abi_version() is not listed. When it advertises maxMemoryBytes it MUST enforce it and emit cap.breached with kind: "wasm-memory" on a breach. nodePackRuntimes.wasmComponent advertises wasm-component loading; its interfaces are reserved for a later RFC.
The MCP registry record
RFC 0203 (Accepted): a remote runtime MAY carry mcpServer, an inline subset of an MCP Registry server.json (schema 2025-12-11): name, description, version, optional title, websiteUrl and repository, and exactly one remotes[] entry of type: "streamable-http" with an https:// URL. It has no packages[], headers, variables or _meta, so it carries no install instruction and no credential. mcpServer under any other language, or an entry that differs from remotes[0].url, makes the manifest invalid (pack_validation_failed). The record is by value; this contract defines no registry lookup. A host SHOULD NOT treat name as a verified identity: an inline record carries no proof of namespace ownership. A host that authenticates to the server does so through the node's requiredCredentials or auth.