feat(cloudflare/workers-for-platforms): dispatch namespace binding + deploy workers into namespaces

[sam-goodwin]

Add the Workers for Platforms dynamic-dispatch binding and let a Worker deploy into a dispatch namespace as a "user worker" — no duplicate Worker resource.

Bind a dispatch namespace to a platform Worker

Two interchangeable styles, both emitting the native dispatch_namespace binding:

// Effect-native — yield the binding, get a typed client
const dispatch = yield* Cloudflare.WorkersForPlatforms.Get(namespace);
const userWorker = yield* dispatch.get("customer-a"); // Effect<Fetcher, DispatchNamespaceError, RuntimeContext>

// Async / InferEnv — pass the namespace on env, call it directly
const platform = Cloudflare.Worker("Platform", {
  main: "./handler.ts",
  env: { DISPATCH: namespace },          // DispatchNamespace is now a valid env binding
});
type Env = Cloudflare.InferEnv<typeof platform>; // env.DISPATCH : cf.DispatchNamespace

// handler.ts
export default {
  async fetch(request: Request, env: Env) {
    return env.DISPATCH.get("customer-a").fetch(request);
  },
};

Provide Cloudflare.WorkersForPlatforms.GetBinding on the Worker's runtime layer for the Effect-native path.

Worker namespace prop — deploy into a namespace

const ns = yield* Cloudflare.WorkersForPlatforms.DispatchNamespace("Customers", {});
const userWorker = yield* Cloudflare.Worker("CustomerA", {
  namespace: ns.name, // string | DispatchNamespace
  script: `export default { fetch() { return new Response("hi") } }`,
});

The provider switches its put/read/delete/settings calls to the dispatch/namespaces/:ns/scripts endpoints when namespace is set, skips the (inapplicable) subdomain / custom-domain / workers.dev / cron reconciliation and the precreate placeholder, and replaces the Worker if it moves into/out of/between namespaces. Reference the namespace via ns.name (an Output) so it resolves and orders correctly.

Tests

DispatchBinding.test.ts deploys a namespace + a user worker in it + two platform workers (Effect-native Get and async env/InferEnv), then drives each over HttpClient (forwards by script name, asserts the dispatched response + header pass-through), plus an unknown-script negative case. Verified live: fresh deploy → dispatch round-trip for both styles → destroy.

Depends on

distilled patch alchemy-run/distilled#361 (typed errors + a placement-union fix for getDispatchNamespaceScriptSetting (append the omitted response variant)); the submodule pointer is bumped to it here.

🤖 Generated with Claude Code

[alchemy-version-bot]

Install the packages built from this commit:

alchemy

bun add alchemy@https://pkg.ing/alchemy/5343c81

@alchemy.run/better-auth

bun add @alchemy.run/better-auth@https://pkg.ing/@alchemy.run/better-auth/5343c81

@alchemy.run/pr-package

bun add @alchemy.run/pr-package@https://pkg.ing/@alchemy.run/pr-package/5343c81