@fabric-harness/cloudflare

Cloudflare Workers + Sandbox adapter for Fabric Harness.

Install

npm install @fabric-harness/cloudflare @fabric-harness/sdk @cloudflare/sandbox

@cloudflare/sandbox is a peer dependency and is required for the sandbox example below. You can omit it when using only the package's persistence, R2, or Workers AI helpers.

Quick start

import { defineAgent } from '@fabric-harness/sdk';
import { getSandbox } from '@cloudflare/sandbox';
import { createCloudflareSandboxEnv } from '@fabric-harness/cloudflare';

export default defineAgent({
  name: 'edge-assistant', triggers: { webhook: true },
  run: async ({ init, payload, env }) => {
    const sandbox = createCloudflareSandboxEnv(getSandbox(env.Sandbox, 'session-1'));
    const session = await (await init({
      sandbox,
      model: 'anthropic/claude-sonnet-4-6',
      runtime: 'stateless',
    })).session();
    return { reply: await session.prompt<string>(String((payload as any)?.message ?? '')) };
  },
});

Build with fh build --target cloudflare to produce an artifact ready for wrangler deploy.

What's in the box

• createCloudflareSandboxEnv(sandbox, options?) — adapts getSandbox(env.Sandbox, id) from @cloudflare/sandbox into a Fabric SandboxEnv.
• createCloudflareDurableObjectSessionStore(sql, options?) — durable-object-backed session store with optional R2 routing for large artifacts (configurable r2ThresholdBytes, r2KeyPrefix).
• createCloudflareRunRegistry(sql) — tenant-aware pointer index used to list finite runs across per-run Durable Objects.
• createCloudflareRunRegistryClient(namespace) and handleCloudflareRunRegistryRequest(...) — private Worker-to-registry protocol used by generated Cloudflare artifacts. Per-run objects remain authoritative; terminal upserts heal missed starts.
• r2FilesystemSource(bucket, options?) — mount an R2 bucket prefix as a read-only FilesystemSource. Use with session.mount().

Documentation

• Cloudflare deployment
• Sandboxes
• Filesystem sources

License

Apache-2.0