ai-isolate-cloudflare: unsafe_eval is gated by Cloudflare; port to worker_loader

[Sriketk]

TanStack AI version

0.1.8

Framework/Library version

@tanstack/ai-isolate-cloudflare@0.1.8

Describe the bug

The ai-isolate-cloudflare worker hardcodes env.UNSAFE_EVAL.eval(code). The unsafe_eval binding is workerd-internal and gated by Cloudflare for all customer accounts — there is no public entitlement and no path to enable it.

Result: the package is unusable in production and broken in wrangler dev on current Wrangler 4.x.

Reproduction

wrangler.toml per the README:

[[unsafe.bindings]]
name = "UNSAFE_EVAL"
type = "eval"

Attempt	Wrangler	Result
wrangler deploy	4.87	binding UNSAFE_EVAL has an unknown type eval [code: 10021]
wrangler dev (default = remote)	4.87	binding mode remote, runtime returns UnsafeEvalNotAvailable
wrangler dev --local	3.114	Fatal: setsocketopt TCP_NODELAY crash

Root cause

unsafe_eval was never publicly enrolled. The cloudflare.com/products/workers-unsafe-eval/ page is dead. Cloudflare's supported replacement is the worker_loader (Dynamic Workers) binding, GA-beta'd 2026-03-24.

Suggested fix

Swap the worker's eval call:

// before
const result = await env.UNSAFE_EVAL.eval(wrappedCode);

// after
const child = env.LOADER.load({
  compatibilityDate: "2026-05-01",
  mainModule: "main.js",
  modules: { "main.js": wrapAsModule(wrappedCode) },
  globalOutbound: null,
});
const resp = await child.getEntrypoint().fetch(new Request("https://sandbox.invalid/"));
const result = await resp.json();

wrapAsModule wraps the existing IIFE in export default { fetch() { ... } }, returns JSON. ~40 LOC change in worker, driver/protocol untouched, public API unchanged. Requires Workers Paid plan (CF API rejects worker_loader on Free with code: 10195; same plan tier unsafe_eval would have required).

Validation

I have a working bun patch of 0.1.8 deployed against a real CF Worker (worker_loader binding accepted, e2e passing for HTTP tool-callback round-trip). PR incoming.

Refs

• Cloudflare Dynamic Workers docs
• Pricing