# `@wrnexus/rpc`

Define a service contract in a shared workspace package, then import that same contract from the caller and callee.

```ts
import {
  defineService,
  implement,
  inProcessTransport,
  procedure,
  serviceClient,
} from "@wrnexus/rpc";
import { v } from "@wrnexus/validation";

const greeter = defineService({
  name: "greeter",
  procedures: {
    greet: procedure
      .input(v.object({ name: v.string() }))
      .output<{ message: string }>()
      .build(),
  },
});

const service = implement(
  greeter,
  { greet: async ({ name }) => ({ message: `Hello, ${name}` }) },
  { selfApp: "greeter" },
);

const client = serviceClient(greeter, {
  app: "greeter",
  transport: inProcessTransport({
    "greeter/greet": (input, identity) => service.invoke("greet", input, identity),
  }),
});
await client.greet({ name: "Ada" });
```

Service files default-export `implement(...)` from `app/services`. The development server mounts them under the private `/__wrnexus/rpc` prefix.

Pass `{ as: ctx }` to `serviceClient` to propagate the subject. The signed token contains only subject and tenant identifiers; permissions are always checked by the callee. Set `WRNEXUS_RPC_SECRET` in every app, use at least 32 characters, and never reuse the session secret.

Calls time out by default. Retrying is intentionally deferred; when introduced, only procedures marked `.idempotent()` may be retried.