@insler/rpc/context

Context is per-request metadata — an identity, a tenant, a trace — defined by zod schemas on the contract, separate from method input. This entrypoint owns the Propagator abstraction that moves context values into and out of a string-keyed carrier (request metadata):

import { createPropagator, type Propagator } from '@insler/rpc/context';
import { jsonSerde } from '@insler/serde';

const propagator: Propagator = createPropagator(jsonSerde);

const carrier: Record<string, string> = {};
propagator.inject({ identity: { userId: 'u_1' } }, carrier);
propagator.extract(['identity'], carrier); // { identity: { userId: 'u_1' } }

• inject(context, carrier) encodes each context value via the serde.
• extract(keys, carrier) decodes only the keys you ask for — driven by the contract’s context schema keys.

What it does not own

What context means lives on the contract (/contract); the wire serde itself is @insler/serde; validation happens on the host. This layer only maps Record<string, unknown> to Record<string, string> metadata and back.

Use it well

The client and host each default to a JSON-stringify propagator and accept a propagator option. Supply a custom one when context encoding must differ — for example, trace headers in a specific wire format.