runtime

One plugin runtime for the Hanzo estate: a module declares what it exports, and a caller invokes an export by name with JSON in and JSON out. What language the module is written in is a property of the module, not of the caller.

type Module interface {
	Name() string
	Runtime() string
	Exports() []string
	Invoke(ctx context.Context, fn string, payload []byte) ([]byte, error)
}

That interface is zip's. This module implements it rather than declaring its own copy, which is the whole reason it exists: the same contract was written down twice — once in zip, once beside the loader — and only structural typing kept the two honest.

The runtimes

runtime	language	how
native	Go	in-process, no boundary
goja	JavaScript, TypeScript	in-process, no Node
wazero	Rust, and anything else	compiled to WebAssembly ahead of time
pyvm	Python	CPython via cgo, PEP 684 sub-interpreters — build tag pyvm

wazero is why this list is not a list of four languages. Anything that compiles to WebAssembly arrives without a new runner, and Rust is the first caller of that door rather than a special case built for it.

A module declares itself

extension.json, beside the module:

{
  "name": "brave-search",
  "version": "1.0.0",
  "runtime": "goja",
  "module": "index.js",
  "exports": ["search"]
}

Exports is the contract. A caller reads it to know what can be invoked, and nothing else has to be registered anywhere — which is what lets one registry publish a Go action and a Python one side by side.