docs: add Cloudflare Sandbox SDK deployment guide

- Add docs/deploy/cloudflare.mdx with full deployment guide
- Add examples/cloudflare/ with working Worker code
- Update docs navigation to include Cloudflare option
- Update deploy index page with Cloudflare card

The example shows how to run sandbox-agent inside a Cloudflare Sandbox
with exposed ports for API access.

Co-authored-by: Shelley <shelley@exe.dev>

examples/cloudflare/.gitignore

@@ -0,0 +1,3 @@
+node_modules/
+.wrangler/
+.dev.vars

examples/cloudflare/README.md

@@ -0,0 +1,46 @@
+# Cloudflare Sandbox Agent Example
+
+Deploy sandbox-agent inside a Cloudflare Sandbox.
+
+## Prerequisites
+
+- Cloudflare account with Workers Paid plan
+- Docker running locally for `wrangler dev`
+- `ANTHROPIC_API_KEY` or `OPENAI_API_KEY` for the coding agents
+
+## Setup
+
+1. Install dependencies:
+
+```bash
+pnpm install
+```
+
+2. Create `.dev.vars` with your API keys:
+
+```bash
+echo "ANTHROPIC_API_KEY=your-api-key" > .dev.vars
+```
+
+## Development
+
+Start the development server:
+
+```bash
+pnpm run dev
+```
+
+Test the endpoint:
+
+```bash
+curl http://localhost:8787
+```
+
+## Deploy
+
+```bash
+pnpm run deploy
+```
+
+Note: Production preview URLs require a custom domain with wildcard DNS routing.
+See [Cloudflare Production Deployment](https://developers.cloudflare.com/sandbox/guides/production-deployment/) for details.

examples/cloudflare/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "@sandbox-agent/example-cloudflare",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "wrangler dev",
+    "deploy": "wrangler deploy",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@cloudflare/sandbox": "latest"
+  },
+  "devDependencies": {
+    "@cloudflare/workers-types": "latest",
+    "@types/node": "latest",
+    "typescript": "latest",
+    "vitest": "^3.0.0",
+    "wrangler": "latest"
+  }
+}

examples/cloudflare/src/cloudflare.ts

@@ -0,0 +1,52 @@
+import { getSandbox, proxyToSandbox, type Sandbox } from "@cloudflare/sandbox";
+export { Sandbox } from "@cloudflare/sandbox";
+
+type Env = {
+  Sandbox: DurableObjectNamespace<Sandbox>;
+  ANTHROPIC_API_KEY?: string;
+  OPENAI_API_KEY?: string;
+};
+
+export default {
+  async fetch(request: Request, env: Env): Promise<Response> {
+    // Proxy requests to exposed ports first
+    const proxyResponse = await proxyToSandbox(request, env);
+    if (proxyResponse) return proxyResponse;
+
+    const { hostname } = new URL(request.url);
+    const sandbox = getSandbox(env.Sandbox, "sandbox-agent");
+
+    console.log("Installing sandbox-agent...");
+    await sandbox.exec(
+      "curl -fsSL https://releases.rivet.dev/sandbox-agent/latest/install.sh | sh"
+    );
+
+    console.log("Installing agents...");
+    await sandbox.exec("sandbox-agent install-agent claude");
+    await sandbox.exec("sandbox-agent install-agent codex");
+
+    // Set environment variables for agents
+    const envVars: Record<string, string> = {};
+    if (env.ANTHROPIC_API_KEY) envVars.ANTHROPIC_API_KEY = env.ANTHROPIC_API_KEY;
+    if (env.OPENAI_API_KEY) envVars.OPENAI_API_KEY = env.OPENAI_API_KEY;
+    await sandbox.setEnvVars(envVars);
+
+    console.log("Starting sandbox-agent server...");
+    await sandbox.startProcess(
+      "sandbox-agent server --no-token --host 0.0.0.0 --port 8000"
+    );
+
+    // Wait for server to start
+    await new Promise((r) => setTimeout(r, 2000));
+
+    // Expose the port with a preview URL
+    const exposed = await sandbox.exposePort(8000, { hostname });
+
+    console.log("Server accessible at:", exposed.url);
+
+    return Response.json({
+      endpoint: exposed.url,
+      message: "sandbox-agent server is running",
+    });
+  },
+};

examples/cloudflare/tsconfig.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "target": "esnext",
+    "lib": ["esnext"],
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "types": ["@cloudflare/workers-types"],
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "noEmit": true
+  },
+  "include": ["src/**/*.ts"]
+}

examples/cloudflare/wrangler.jsonc

@@ -0,0 +1,29 @@
+{
+  "$schema": "node_modules/wrangler/config-schema.json",
+  "name": "sandbox-agent-cloudflare",
+  "main": "src/cloudflare.ts",
+  "compatibility_date": "2025-01-01",
+  "compatibility_flags": ["nodejs_compat"],
+  "containers": [
+    {
+      "class_name": "Sandbox",
+      "image": "docker.io/cloudflare/sandbox:latest",
+      "instance_type": "lite",
+      "max_instances": 1
+    }
+  ],
+  "durable_objects": {
+    "bindings": [
+      {
+        "class_name": "Sandbox",
+        "name": "Sandbox"
+      }
+    ]
+  },
+  "migrations": [
+    {
+      "new_sqlite_classes": ["Sandbox"],
+      "tag": "v1"
+    }
+  ]
+}