fix(cloudflare): Fix instrumentDurableObjectWithSentry breaking Cloudflare Agents (#21101)

By investigating #20099 it seemed that Cloudflare Agents were not
working when `enableRpcTracePropagation: true` was set. The main reason
for that was that the original target was not bound to the call.

By doing that I changed the logic a little to also make it more
resistant. As the `rpc` trace was always everywhere attached, even
though it could be that it was not directly a real RPC call. No the
`rpc` trace is only attached when in the arguments the
`__sentry_rpc_meta__` is there as last parameter - which gives an extra
layer of safety.

Also `BUILT_IN_DO_METHODS` is not needed and got removed, as we actually
ignore these with the other checks (test was added for it)

The deprecated `instrumentPrototypeMethods` is still using the previous
behavior.

This PR also proofs that we can instrument Agents on Cloudflare
(`cloudflare-agent` e2e test)

--- 
AI text on top:

The fix binds ALL methods to the original object, ensuring private
fields
work correctly. Additionally, spans are now only created when Sentry RPC
metadata (`__sentry_rpc_meta__`) is present in the arguments, which is
only
the case for actual RPC calls that have trace propagation enabled on the
calling side. This prevents creating spans for internal framework method
calls like those made by the Agents SDK over WebSocket.

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: JPeer264

dev-packages/cloudflare-integration-tests/suites/tracing/durableobject-alarm-links-sync/index.ts

@@ -35,6 +35,7 @@ export default Sentry.withSentry(
   (env: Env) => ({
     dsn: env.SENTRY_DSN,
     tracesSampleRate: 1.0,
+    enableRpcTracePropagation: true,
   }),
   {
     async fetch(request: Request, env: Env): Promise<Response> {

dev-packages/cloudflare-integration-tests/suites/tracing/durableobject-alarm-links/index.ts

@@ -33,6 +33,7 @@ export default Sentry.withSentry(
   (env: Env) => ({
     dsn: env.SENTRY_DSN,
     tracesSampleRate: 1.0,
+    enableRpcTracePropagation: true,
   }),
   {
     async fetch(request: Request, env: Env): Promise<Response> {

dev-packages/cloudflare-integration-tests/suites/tracing/durableobject/index.ts

@@ -50,23 +50,30 @@ export const TestDurableObject = Sentry.instrumentDurableObjectWithSentry(
   TestDurableObjectBase,
 );
 
-export default {
-  async fetch(request: Request, env: Env): Promise<Response> {
-    const id: DurableObjectId = env.TEST_DURABLE_OBJECT.idFromName('test');
-    const stub = env.TEST_DURABLE_OBJECT.get(id) as unknown as TestDurableObjectBase;
+export default Sentry.withSentry(
+  (env: Env) => ({
+    dsn: env.SENTRY_DSN,
+    tracesSampleRate: 1.0,
+    enableRpcTracePropagation: true,
+  }),
+  {
+    async fetch(request: Request, env: Env): Promise<Response> {
+      const id: DurableObjectId = env.TEST_DURABLE_OBJECT.idFromName('test');
+      const stub = env.TEST_DURABLE_OBJECT.get(id) as unknown as TestDurableObjectBase;
 
-    if (request.url.includes('hello')) {
-      const greeting = await stub.sayHello('world');
-      return new Response(greeting);
-    }
+      if (request.url.includes('hello')) {
+        const greeting = await stub.sayHello('world');
+        return new Response(greeting);
+      }
 
-    // Test endpoint that modifies and reads a private field via RPC
-    if (request.url.includes('custom-greeting')) {
-      await stub.setGreeting('Howdy');
-      const greeting = await stub.sayHello('partner');
-      return new Response(greeting);
-    }
+      // Test endpoint that modifies and reads a private field via RPC
+      if (request.url.includes('custom-greeting')) {
+        await stub.setGreeting('Howdy');
+        const greeting = await stub.sayHello('partner');
+        return new Response(greeting);
+      }
 
-    return new Response('Usual response');
-  },
-};
+      return new Response('Usual response');
+    },
+  } satisfies ExportedHandler<Env>,
+);

dev-packages/e2e-tests/test-applications/cloudflare-agent/index.html

@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>temp-cloudflare-react</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>

dev-packages/e2e-tests/test-applications/cloudflare-agent/package.json

@@ -0,0 +1,42 @@
+{
+  "name": "cloudflare-agent",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "preview": "vite preview",
+    "cf-typegen": "wrangler types --include-runtime=false",
+    "test:build": "pnpm install && pnpm build",
+    "test:assert": "pnpm test:dev && pnpm test:prod",
+    "test:prod": "TEST_ENV=production playwright test",
+    "test:dev": "TEST_ENV=development playwright test"
+  },
+  "dependencies": {
+    "@cloudflare/ai-chat": "^0.7.1",
+    "@sentry/cloudflare": "^10.53.1",
+    "agents": "^0.13.1",
+    "react": "^19.2.6",
+    "react-dom": "^19.2.6"
+  },
+  "devDependencies": {
+    "@playwright/test": "~1.56.0",
+    "@cloudflare/vite-plugin": "^1.37.2",
+    "@cloudflare/workers-types": "^4.20260520.1",
+    "@sentry-internal/test-utils": "link:../../../test-utils",
+    "@types/node": "^24.12.4",
+    "@types/react": "^19.2.15",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.2",
+    "globals": "^17.6.0",
+    "typescript": "~6.0.3",
+    "vite": "^8.0.14",
+    "wrangler": "^4.93.0",
+    "ws": "^8.20.1"
+  },
+  "volta": {
+    "node": "24.15.0",
+    "extends": "../../package.json"
+  }
+}

dev-packages/e2e-tests/test-applications/cloudflare-agent/playwright.config.ts

@@ -0,0 +1,10 @@
+import { getPlaywrightConfig } from '@sentry-internal/test-utils';
+
+export default getPlaywrightConfig({
+  testDir: './tests',
+  port: 4173,
+  startCommand: 'pnpm preview',
+  use: {
+    baseURL: 'http://localhost:4173',
+  },
+});

dev-packages/e2e-tests/test-applications/cloudflare-agent/src/App.tsx

@@ -0,0 +1,47 @@
+import { useState } from 'react';
+import { useAgent } from 'agents/react';
+
+function App() {
+  const [greeting, setGreeting] = useState('');
+  const [connected, setConnected] = useState(false);
+
+  const agent = useAgent({
+    agent: 'my-agent',
+    name: 'user-123',
+    onOpen: () => setConnected(true),
+    onClose: () => setConnected(false),
+  });
+
+  const handleGreet = async () => {
+    if (!connected) {
+      setGreeting('Not connected yet...');
+      return;
+    }
+    try {
+      const result = await agent.call('greet', ['World']);
+      setGreeting(result as string);
+    } catch (err) {
+      setGreeting(`Error: ${err}`);
+      console.error('Agent call failed:', err);
+    }
+  };
+
+  return (
+    <div
+      style={{
+        display: 'flex',
+        flexDirection: 'column',
+        alignItems: 'center',
+        justifyContent: 'center',
+        minHeight: '100vh',
+        gap: '1rem',
+      }}
+    >
+      <button onClick={handleGreet}>Call Agent</button>
+      {greeting && <p>{greeting}</p>}
+      <p style={{ fontSize: '0.8rem', color: '#666' }}>{connected ? 'Connected' : 'Connecting...'}</p>
+    </div>
+  );
+}
+
+export default App;

dev-packages/e2e-tests/test-applications/cloudflare-agent/src/main.tsx

@@ -0,0 +1,9 @@
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+import App from './App.tsx';
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <App />
+  </StrictMode>,
+);

dev-packages/e2e-tests/test-applications/cloudflare-agent/start-event-proxy.mjs

@@ -0,0 +1,3 @@
+import { startEventProxyServer } from '@sentry-internal/test-utils';
+
+startEventProxyServer({ port: 3031, proxyServerName: 'cloudflare-agent' });

dev-packages/e2e-tests/test-applications/cloudflare-agent/tests/callable.test.ts

@@ -0,0 +1,63 @@
+import { expect, test } from '@playwright/test';
+import { waitForTransaction } from '@sentry-internal/test-utils';
+
+test('@callable() methods work correctly with Sentry instrumentDurableObjectWithSentry', async ({ page, baseURL }) => {
+  const transactionPromise = waitForTransaction('cloudflare-agent', transactionEvent => {
+    return (
+      transactionEvent.transaction === 'GET /agents/my-agent/user-123' &&
+      transactionEvent.contexts?.trace?.parent_span_id !== undefined
+    );
+  });
+
+  await page.goto(baseURL!);
+
+  await expect(page.getByText('Connected')).toBeVisible();
+  await page.getByRole('button', { name: 'Call Agent' }).click();
+  await expect(page.getByText('Hello, World!')).toBeVisible();
+
+  const transaction = await transactionPromise;
+
+  expect(transaction).toEqual({
+    contexts: {
+      trace: {
+        parent_span_id: expect.stringMatching(/[a-f0-9]{16}/),
+        span_id: expect.stringMatching(/[a-f0-9]{16}/),
+        trace_id: expect.stringMatching(/[a-f0-9]{32}/),
+        data: expect.any(Object),
+        op: 'http.server',
+        status: 'ok',
+        origin: 'auto.http.cloudflare',
+      },
+      cloud_resource: { 'cloud.provider': 'cloudflare' },
+      culture: { timezone: expect.any(String) },
+      runtime: { name: 'cloudflare' },
+    },
+    spans: expect.arrayContaining([
+      expect.objectContaining({
+        op: 'db',
+        description: 'durable_object_storage_get',
+      }),
+    ]),
+    start_timestamp: expect.any(Number),
+    timestamp: expect.any(Number),
+    transaction: 'GET /agents/my-agent/user-123',
+    type: 'transaction',
+    request: {
+      headers: expect.any(Object),
+      method: 'GET',
+      url: expect.stringContaining('/agents/my-agent/user-123'),
+      query_string: expect.any(String),
+    },
+    transaction_info: { source: 'url' },
+    platform: 'javascript',
+    event_id: expect.stringMatching(/[a-f0-9]{32}/),
+    environment: expect.any(String),
+    release: expect.any(String),
+    sdk: {
+      integrations: expect.any(Array),
+      name: 'sentry.javascript.cloudflare',
+      version: expect.any(String),
+      packages: expect.any(Array),
+    },
+  });
+});