test(e2e): Add MCP auto-instrumentation e2e apps

.size-limit.js

@@ -406,7 +406,7 @@ module.exports = [
     import: createImport('init'),
     ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
     gzip: true,
-    limit: '139 KB',
+    limit: '142 KB',
     disablePlugins: ['@size-limit/esbuild'],
   },
   {

dev-packages/bun-integration-tests/node-suites/excludes.ts

@@ -101,7 +101,7 @@ const NO_AUTO_INSTRUMENTATION = [
   'suites/tracing/lru-memoizer/test.ts',
   'suites/tracing/mastra/test.ts',
   'suites/tracing/mcp-handler-exact-once/test.ts',
-  'suites/tracing/mcp-server-streamed/test.ts',
+  'suites/tracing/mcp-server/**',
   'suites/tracing/mistral/test.ts',
   'suites/tracing/mongodb-v4/test.ts',
   'suites/tracing/mongodb-v5/test.ts',

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/instrument.mjs

@@ -0,0 +1,9 @@
+import * as Sentry from '@sentry/node';
+
+Sentry.init({
+  environment: 'qa', // dynamic sampling bias to keep transactions
+  dsn: process.env.E2E_TEST_DSN,
+  debug: !!process.env.DEBUG,
+  tunnel: `http://localhost:3031/`, // proxy server
+  tracesSampleRate: 1,
+});

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "node-express-mcp-v1-app",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "build": "tsc",
+    "start": "node --import ./instrument.mjs dist/app.js",
+    "test": "playwright test",
+    "clean": "npx rimraf node_modules pnpm-lock.yaml",
+    "test:build": "pnpm install && pnpm build",
+    "test:assert": "pnpm test"
+  },
+  "dependencies": {
+    "@modelcontextprotocol/sdk": "^1.26.0",
+    "@sentry/node": "file:../../packed/sentry-node-packed.tgz",
+    "@types/express": "^4.17.21",
+    "@types/node": "^18.19.1",
+    "express": "^4.21.2",
+    "typescript": "~5.0.0",
+    "zod": "~3.25.0"
+  },
+  "devDependencies": {
+    "@playwright/test": "~1.63.0",
+    "@sentry-internal/test-utils": "link:../../../test-utils",
+    "@sentry/core": "file:../../packed/sentry-core-packed.tgz"
+  },
+  "type": "module",
+  "volta": {
+    "extends": "../../package.json"
+  },
+  "sentryTest": {
+    "optional": true
+  }
+}

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/playwright.config.mjs

@@ -0,0 +1,7 @@
+import { getPlaywrightConfig } from '@sentry-internal/test-utils';
+
+const config = getPlaywrightConfig({
+  startCommand: `pnpm start`,
+});
+
+export default config;

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/src/app.ts

@@ -0,0 +1,17 @@
+import * as Sentry from '@sentry/node';
+import express from 'express';
+import { mcpRouter } from './mcp.js';
+
+const app = express();
+const port = 3030;
+
+app.use(express.json());
+app.use(mcpRouter);
+
+app.get('/test-success', function (_req, res) {
+  res.send({ version: 'v1' });
+});
+
+app.listen(port, () => {
+  console.log(`Example app listening on port ${port}`);
+});

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/src/mcp.ts

@@ -0,0 +1,120 @@
+import { randomUUID } from 'node:crypto';
+import express from 'express';
+import { McpServer, ResourceTemplate } from '@modelcontextprotocol/sdk/server/mcp.js';
+import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
+import { z } from 'zod';
+
+const mcpRouter = express.Router();
+
+// Intentionally NOT wrapped with `wrapMcpServerWithSentry`: the `mcpServer` integration
+// auto-instruments the `McpServer` constructor, so spans must be produced anyway.
+const server = new McpServer({
+  name: 'Echo-V1',
+  version: '1.0.0',
+});
+
+server.registerResource(
+  'echo',
+  new ResourceTemplate('echo://{message}', { list: undefined }),
+  { title: 'Echo Resource' },
+  async (uri, { message }) => ({
+    contents: [
+      {
+        uri: uri.href,
+        text: `Resource echo: ${message}`,
+      },
+    ],
+  }),
+);
+
+server.registerTool(
+  'echo',
+  { description: 'Echo tool', inputSchema: { message: z.string() } },
+  async ({ message }) => ({
+    content: [{ type: 'text', text: `Tool echo: ${message}` }],
+  }),
+);
+
+server.registerPrompt('echo', { description: 'Echo prompt', argsSchema: { message: z.string() } }, ({ message }) => ({
+  messages: [
+    {
+      role: 'user',
+      content: {
+        type: 'text',
+        text: `Please process this message: ${message}`,
+      },
+    },
+  ],
+}));
+
+server.registerTool('always-error', {}, async () => {
+  throw new Error('intentional error for span status testing');
+});
+
+const transports: Record<string, StreamableHTTPServerTransport> = {};
+
+mcpRouter.post('/mcp', async (req, res) => {
+  const sessionId = req.headers['mcp-session-id'] as string | undefined;
+
+  try {
+    let transport: StreamableHTTPServerTransport;
+
+    if (sessionId && transports[sessionId]) {
+      transport = transports[sessionId];
+    } else if (!sessionId && req.body?.method === 'initialize') {
+      transport = new StreamableHTTPServerTransport({
+        sessionIdGenerator: () => randomUUID(),
+        onsessioninitialized: sid => {
+          transports[sid] = transport;
+        },
+      });
+
+      transport.onclose = () => {
+        const sid = transport.sessionId;
+        if (sid && transports[sid]) {
+          delete transports[sid];
+        }
+      };
+
+      await server.connect(transport);
+    } else {
+      res.status(400).json({
+        jsonrpc: '2.0',
+        error: { code: -32000, message: 'Bad Request: No valid session ID provided' },
+        id: null,
+      });
+      return;
+    }
+
+    await transport.handleRequest(req, res, req.body);
+  } catch (error) {
+    console.error('Error handling MCP request:', error);
+    if (!res.headersSent) {
+      res.status(500).json({
+        jsonrpc: '2.0',
+        error: { code: -32603, message: 'Internal server error' },
+        id: null,
+      });
+    }
+  }
+});
+
+mcpRouter.get('/mcp', async (req, res) => {
+  const sessionId = req.headers['mcp-session-id'] as string | undefined;
+  if (!sessionId || !transports[sessionId]) {
+    res.status(400).send('Invalid or missing session ID');
+    return;
+  }
+  await transports[sessionId].handleRequest(req, res);
+});
+
+mcpRouter.delete('/mcp', async (req, res) => {
+  const sessionId = req.headers['mcp-session-id'] as string | undefined;
+  if (!sessionId || !transports[sessionId]) {
+    res.status(400).send('Invalid or missing session ID');
+    return;
+  }
+  await transports[sessionId].handleRequest(req, res);
+});
+
+export { mcpRouter };

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/start-event-proxy.mjs

@@ -0,0 +1,6 @@
+import { startEventProxyServer } from '@sentry-internal/test-utils';
+
+startEventProxyServer({
+  port: 3031,
+  proxyServerName: 'node-express-mcp-v1',
+});

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/tests/mcp.test.ts

@@ -0,0 +1,100 @@
+import { expect, test } from '@playwright/test';
+import { waitForStreamedSpan, getSpanOp } from '@sentry-internal/test-utils';
+import { Client } from '@modelcontextprotocol/sdk/client/index.js';
+import { StreamableHTTPClientTransport } from '@modelcontextprotocol/sdk/client/streamableHttp.js';
+
+// The server in this app is never wrapped with `wrapMcpServerWithSentry` — spans are produced
+// solely by the auto-instrumenting `mcpServer` integration against the legacy v1 SDK.
+test('auto-instruments a legacy MCP SDK v1 server (no manual wrap)', async ({ baseURL }) => {
+  const transport = new StreamableHTTPClientTransport(new URL(`${baseURL}/mcp`));
+
+  const client = new Client({
+    name: 'test-client-v1',
+    version: '1.0.0',
+  });
+
+  const initializeSegmentPromise = waitForStreamedSpan(
+    'node-express-mcp-v1',
+    segment => segment.is_segment && segment.name === 'initialize',
+  );
+
+  await client.connect(transport);
+
+  await test.step('initialize handshake', async () => {
+    const initializeSegment = await initializeSegmentPromise;
+    expect(initializeSegment).toBeDefined();
+    expect(getSpanOp(initializeSegment)).toEqual('mcp.server');
+    expect(initializeSegment.attributes?.['mcp.method.name']?.value).toEqual('initialize');
+    expect(initializeSegment.attributes?.['mcp.client.name']?.value).toEqual('test-client-v1');
+    expect(initializeSegment.attributes?.['mcp.server.name']?.value).toEqual('Echo-V1');
+  });
+
+  await test.step('tool call', async () => {
+    const toolSegmentPromise = waitForStreamedSpan(
+      'node-express-mcp-v1',
+      segment => segment.is_segment && segment.name === 'tools/call echo',
+    );
+
+    const toolResult = await client.callTool({
+      name: 'echo',
+      arguments: {
+        message: 'foobar',
+      },
+    });
+
+    expect(toolResult).toMatchObject({
+      content: [
+        {
+          text: 'Tool echo: foobar',
+          type: 'text',
+        },
+      ],
+    });
+
+    const toolSegment = await toolSegmentPromise;
+    expect(toolSegment).toBeDefined();
+    expect(getSpanOp(toolSegment)).toEqual('mcp.server');
+    expect(toolSegment.attributes?.['mcp.method.name']?.value).toEqual('tools/call');
+    expect(toolSegment.attributes?.['mcp.tool.name']?.value).toEqual('echo');
+  });
+
+  await test.step('resource read', async () => {
+    const resourceSegmentPromise = waitForStreamedSpan(
+      'node-express-mcp-v1',
+      segment => segment.is_segment && segment.name === 'resources/read',
+    );
+
+    const resourceResult = await client.readResource({
+      uri: 'echo://foobar',
+    });
+
+    expect(resourceResult).toMatchObject({
+      contents: [{ text: 'Resource echo: foobar', uri: 'echo://foobar' }],
+    });
+
+    const resourceSegment = await resourceSegmentPromise;
+    expect(resourceSegment).toBeDefined();
+    expect(getSpanOp(resourceSegment)).toEqual('mcp.server');
+    expect(resourceSegment.attributes?.['mcp.method.name']?.value).toEqual('resources/read');
+  });
+
+  await test.step('error tool sets span status to error', async () => {
+    const toolSegmentPromise = waitForStreamedSpan(
+      'node-express-mcp-v1',
+      segment => segment.is_segment && segment.name === 'tools/call always-error',
+    );
+
+    try {
+      await client.callTool({ name: 'always-error', arguments: {} });
+    } catch {
+      // Expected: MCP SDK throws when the tool returns a JSON-RPC error
+    }
+
+    const toolSegment = await toolSegmentPromise;
+    expect(toolSegment).toBeDefined();
+    expect(getSpanOp(toolSegment)).toEqual('mcp.server');
+    expect(toolSegment?.status).toEqual('error');
+  });
+
+  await client.close();
+});

dev-packages/e2e-tests/test-applications/node-express-mcp-v1/tsconfig.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "types": ["node"],
+    "esModuleInterop": true,
+    "lib": ["es2020"],
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "strict": true,
+    "outDir": "dist",
+    "skipLibCheck": true
+  },
+  "include": ["src/**/*.ts"]
+}

dev-packages/e2e-tests/test-applications/node-express-mcp-v2/src/mcp.ts

@@ -3,16 +3,15 @@ import express from 'express';
 import { McpServer, ResourceTemplate } from '@modelcontextprotocol/server';
 import { NodeStreamableHTTPServerTransport } from '@modelcontextprotocol/node';
 import { z } from 'zod';
-import { wrapMcpServerWithSentry } from '@sentry/node';
 
 const mcpRouter = express.Router();
 
-const server = wrapMcpServerWithSentry(
-  new McpServer({
-    name: 'Echo-V2',
-    version: '2.0.0',
-  }),
-);
+// Intentionally NOT wrapped with `wrapMcpServerWithSentry`: the `mcpServer` integration
+// auto-instruments the `McpServer` constructor, so spans must be produced anyway.
+const server = new McpServer({
+  name: 'Echo-V2',
+  version: '2.0.0',
+});
 
 server.registerResource(
   'echo',

dev-packages/e2e-tests/test-applications/node-express-mcp-v2/tests/mcp.test.ts

@@ -3,7 +3,9 @@ import { waitForStreamedSpan, getSpanOp } from '@sentry-internal/test-utils';
 import { Client } from '@modelcontextprotocol/client';
 import { StreamableHTTPClientTransport } from '@modelcontextprotocol/client';
 
-test('records spans for stable MCP SDK v2 handlers using the register API', async ({ baseURL }) => {
+// The server in this app is never wrapped with `wrapMcpServerWithSentry` — spans are produced
+// solely by the auto-instrumenting `mcpServer` integration.
+test('auto-instruments a stable MCP SDK v2 server (no manual wrap)', async ({ baseURL }) => {
   const transport = new StreamableHTTPClientTransport(new URL(`${baseURL}/mcp`));
 
   const client = new Client({