Typed RPC

Define a capability once and share its runtime contract with clients. Query and mutation methods return ordinary promises; stream methods return async iterables. TypeScript infers inputs and results while runtime schemas check peer data.

import { defineCapability, procedure } from '@unstoppable-stack/p2p/rpc'

const noteId = (value: unknown): { id: string } => {
  if (typeof (value as { id?: unknown })?.id !== 'string') throw new Error('Expected id')
  return { id: (value as { id: string }).id }
}
const notes = defineCapability({
  name: 'notes', version: 1,
  methods: {
    get: procedure.input(noteId).query(({ input }) => ({ id: input.id, text: 'Hello' }))
  },
  defaultGrants: ['get']
})
// Host: createNode({ storage, capabilities: [notes] })
// Client: obtain a paired peer and use the shared contract.
const api = peer.client(notes.contract)
const note = await api.get({ id: 'n1' })

• Use procedure.input(schema).output(schema).query(handler), .mutation(handler) or .stream(handler). Validators can be parser functions, parse() objects or Standard Schema implementations.
• Input transformations run once on the host. Output schemas must be idempotent JSON wire validators; stripped fields are removed before transmission and clients validate received output again.
• Return JSON values: dates, maps, undefined, cycles and nonfinite numbers are rejected. Use null for an action with no result data.
• Binding checks service version, method presence and kind. Partial grants are valid; ungranted calls still fail with NOT_GRANTED. Type inference does not authorize a peer.
• Calls accept signal and timeout. Cancellation is cooperative; no mutation or stream is replayed automatically after reconnect. Obtain the replacement peer and bind a fresh client.

Keep contracts and validators in a shared application module. Bind the P2P client in the worker and expose app-owned IPC to the renderer; validator functions cannot be sent as JSON. Streams retain finite request and output budgets and do not implement durable subscriptions.