diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/.gitignore b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/.gitignore
new file mode 100644
index 000000000000..e71378008bf1
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/.gitignore
@@ -0,0 +1 @@
+.wrangler
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/.npmrc b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/.npmrc
new file mode 100644
index 000000000000..070f80f05092
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/.npmrc
@@ -0,0 +1,2 @@
+@sentry:registry=http://127.0.0.1:4873
+@sentry-internal:registry=http://127.0.0.1:4873
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/package.json b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/package.json
new file mode 100644
index 000000000000..686e747422fa
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/package.json
@@ -0,0 +1,41 @@
+{
+  "name": "cloudflare-mcp",
+  "version": "0.0.0",
+  "private": true,
+  "scripts": {
+    "deploy": "wrangler deploy",
+    "dev": "wrangler dev --var \"E2E_TEST_DSN:$E2E_TEST_DSN\" --log-level=$(test $CI && echo 'none' || echo 'log')",
+    "build": "wrangler deploy --dry-run",
+    "test": "vitest --run",
+    "typecheck": "tsc --noEmit",
+    "cf-typegen": "wrangler types",
+    "test:build": "pnpm install && pnpm build",
+    "test:assert": "pnpm typecheck && pnpm test:dev && pnpm test:prod",
+    "test:prod": "TEST_ENV=production playwright test",
+    "test:dev": "TEST_ENV=development playwright test"
+  },
+  "dependencies": {
+    "@modelcontextprotocol/sdk": "^1.22.0",
+    "@sentry/cloudflare": "latest || *",
+    "agents": "^0.2.23",
+    "zod": "^3.25.76"
+  },
+  "devDependencies": {
+    "@cloudflare/vitest-pool-workers": "^0.8.19",
+    "@cloudflare/workers-types": "^4.20240725.0",
+    "@playwright/test": "~1.50.0",
+    "@sentry-internal/test-utils": "link:../../../test-utils",
+    "typescript": "^5.5.2",
+    "vitest": "~3.2.0",
+    "wrangler": "^4.23.0",
+    "ws": "^8.18.3"
+  },
+  "volta": {
+    "extends": "../../package.json"
+  },
+  "pnpm": {
+    "overrides": {
+      "strip-literal": "~2.0.0"
+    }
+  }
+}
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/playwright.config.ts b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/playwright.config.ts
new file mode 100644
index 000000000000..73abbd951b90
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/playwright.config.ts
@@ -0,0 +1,22 @@
+import { getPlaywrightConfig } from '@sentry-internal/test-utils';
+const testEnv = process.env.TEST_ENV;
+
+if (!testEnv) {
+  throw new Error('No test env defined');
+}
+
+const APP_PORT = 38787;
+
+const config = getPlaywrightConfig(
+  {
+    startCommand: `pnpm dev --port ${APP_PORT}`,
+    port: APP_PORT,
+  },
+  {
+    // This comes with the risk of tests leaking into each other but the tests run quite slow so we should parallelize
+    workers: '100%',
+    retries: 0,
+  },
+);
+
+export default config;
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/src/env.d.ts b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/src/env.d.ts
new file mode 100644
index 000000000000..1701ed9f621a
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/src/env.d.ts
@@ -0,0 +1,7 @@
+// Generated by Wrangler on Mon Jul 29 2024 21:44:31 GMT-0400 (Eastern Daylight Time)
+// by running `wrangler types`
+
+interface Env {
+  E2E_TEST_DSN: '';
+  MY_DURABLE_OBJECT: DurableObjectNamespace;
+}
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/src/index.ts b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/src/index.ts
new file mode 100644
index 000000000000..5528ccffd3de
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/src/index.ts
@@ -0,0 +1,83 @@
+/**
+ * Welcome to Cloudflare Workers! This is your first worker.
+ *
+ * - Run `npm run dev` in your terminal to start a development server
+ * - Open a browser tab at http://localhost:8787/ to see your worker in action
+ * - Run `npm run deploy` to publish your worker
+ *
+ * Bind resources to your worker in `wrangler.toml`. After adding bindings, a type definition for the
+ * `Env` object can be regenerated with `npm run cf-typegen`.
+ *
+ * Learn more at https://developers.cloudflare.com/workers/
+ */
+import * as Sentry from '@sentry/cloudflare';
+import { createMcpHandler } from 'agents/mcp';
+import * as z from 'zod';
+import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
+
+export default Sentry.withSentry(
+  (env: Env) => ({
+    dsn: env.E2E_TEST_DSN,
+    environment: 'qa', // dynamic sampling bias to keep transactions
+    tunnel: `http://localhost:3031/`, // proxy server
+    tracesSampleRate: 1.0,
+    sendDefaultPii: true,
+    debug: true,
+    transportOptions: {
+      // We are doing a lot of events at once in this test
+      bufferSize: 1000,
+    },
+  }),
+  {
+    async fetch(request, env, ctx) {
+      const server = new McpServer({
+        name: 'cloudflare-mcp',
+        version: '1.0.0',
+      });
+
+      const span = Sentry.getActiveSpan();
+
+      if (span) {
+        span.setAttribute('mcp.server.extra', ' /|\ ^._.^ /|\ ');
+      }
+
+      server.registerTool(
+        'my-tool',
+        {
+          title: 'My Tool',
+          description: 'My Tool Description',
+          inputSchema: {
+            message: z.string(),
+          },
+        },
+        async ({ message }) => {
+          const span = Sentry.getActiveSpan();
+
+          // simulate a long running tool
+          await new Promise(resolve => setTimeout(resolve, 500));
+
+          if (span) {
+            span.setAttribute('mcp.tool.name', 'my-tool');
+            span.setAttribute('mcp.tool.extra', 'ƸӜƷ');
+            span.setAttribute('mcp.tool.input', JSON.stringify({ message }));
+          }
+
+          return {
+            content: [
+              {
+                type: 'text' as const,
+                text: `Tool my-tool: ${message}`,
+              },
+            ],
+          };
+        },
+      );
+
+      const handler = createMcpHandler(Sentry.wrapMcpServerWithSentry(server), {
+        route: '/mcp',
+      });
+
+      return handler(request, env, ctx);
+    },
+  } satisfies ExportedHandler<Env>,
+);
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/start-event-proxy.mjs b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/start-event-proxy.mjs
new file mode 100644
index 000000000000..da5101c5275f
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/start-event-proxy.mjs
@@ -0,0 +1,6 @@
+import { startEventProxyServer } from '@sentry-internal/test-utils';
+
+startEventProxyServer({
+  port: 3031,
+  proxyServerName: 'cloudflare-mcp',
+});
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tests/index.test.ts b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tests/index.test.ts
new file mode 100644
index 000000000000..8ce8b693499e
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tests/index.test.ts
@@ -0,0 +1,110 @@
+import { expect, test } from '@playwright/test';
+import { waitForRequest } from '@sentry-internal/test-utils';
+
+test('sends spans for MCP tool calls', async ({ baseURL }) => {
+  const spanRequestWaiter = waitForRequest('cloudflare-mcp', event => {
+    const transaction = event.envelope[1][0][1];
+    return typeof transaction !== 'string' && 'transaction' in transaction && transaction.transaction === 'POST /mcp';
+  });
+
+  const spanMcpWaiter = waitForRequest('cloudflare-mcp', event => {
+    const transaction = event.envelope[1][0][1];
+    return (
+      typeof transaction !== 'string' &&
+      'transaction' in transaction &&
+      transaction.transaction === 'tools/call my-tool'
+    );
+  });
+
+  const response = await fetch(`${baseURL}/mcp`, {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      Accept: 'application/json, text/event-stream',
+    },
+    body: JSON.stringify({
+      jsonrpc: '2.0',
+      id: 1,
+      method: 'tools/call',
+      params: {
+        name: 'my-tool',
+        arguments: {
+          message: 'ʕっ•ᴥ•ʔっ',
+        },
+      },
+    }),
+  });
+
+  expect(response.status).toBe(200);
+
+  const requestData = await spanRequestWaiter;
+  const mcpData = await spanMcpWaiter;
+
+  const requestEvent = requestData.envelope[1][0][1];
+  const mcpEvent = mcpData.envelope[1][0][1];
+
+  // Check that the events have contexts
+  // this is for TypeScript type safety
+  if (
+    typeof mcpEvent === 'string' ||
+    !('contexts' in mcpEvent) ||
+    typeof requestEvent === 'string' ||
+    !('contexts' in requestEvent)
+  ) {
+    throw new Error("Events don't have contexts");
+  }
+
+  expect(mcpEvent.contexts?.trace?.trace_id).toBe((mcpData.envelope[0].trace as any).trace_id);
+  expect(requestData.envelope[0].event_id).not.toBe(mcpData.envelope[0].event_id);
+
+  expect(requestEvent.contexts?.trace).toEqual({
+    span_id: expect.any(String),
+    trace_id: expect.any(String),
+    data: expect.objectContaining({
+      'sentry.origin': 'auto.http.cloudflare',
+      'sentry.op': 'http.server',
+      'sentry.source': 'url',
+      'sentry.sample_rate': 1,
+      'http.request.method': 'POST',
+      'url.path': '/mcp',
+      'url.full': 'http://localhost:38787/mcp',
+      'url.port': '38787',
+      'url.scheme': 'http:',
+      'server.address': 'localhost',
+      'http.request.body.size': 120,
+      'user_agent.original': 'node',
+      'http.request.header.content_type': 'application/json',
+      'network.protocol.name': 'HTTP/1.1',
+      'mcp.server.extra': ' /|\ ^._.^ /|\ ',
+      'http.response.status_code': 200,
+    }),
+    op: 'http.server',
+    status: 'ok',
+    origin: 'auto.http.cloudflare',
+  });
+
+  expect(mcpEvent.contexts?.trace).toEqual({
+    trace_id: expect.any(String),
+    parent_span_id: requestEvent.contexts?.trace?.span_id,
+    span_id: expect.any(String),
+    op: 'mcp.server',
+    origin: 'auto.function.mcp_server',
+    data: {
+      'sentry.origin': 'auto.function.mcp_server',
+      'sentry.op': 'mcp.server',
+      'sentry.source': 'route',
+      'mcp.transport': 'WorkerTransport',
+      'network.transport': 'unknown',
+      'network.protocol.version': '2.0',
+      'mcp.method.name': 'tools/call',
+      'mcp.request.id': '1',
+      'mcp.tool.name': 'my-tool',
+      'mcp.request.argument.message': '"ʕっ•ᴥ•ʔっ"',
+      'mcp.tool.extra': 'ƸӜƷ',
+      'mcp.tool.input': '{"message":"ʕっ•ᴥ•ʔっ"}',
+      'mcp.tool.result.content_count': 1,
+      'mcp.tool.result.content_type': 'text',
+      'mcp.tool.result.content': 'Tool my-tool: ʕっ•ᴥ•ʔっ',
+    },
+  });
+});
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tests/tsconfig.json b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tests/tsconfig.json
new file mode 100644
index 000000000000..9a3b10f6cdc8
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tests/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "types": ["@cloudflare/vitest-pool-workers"]
+  },
+  "include": ["./**/*.ts", "../worker-configuration.d.ts"],
+  "exclude": []
+}
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tsconfig.json b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tsconfig.json
new file mode 100644
index 000000000000..87d4bbd5fab8
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/tsconfig.json
@@ -0,0 +1,43 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig.json to read more about this file */
+
+    /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    "target": "es2021",
+    /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    "lib": ["es2021"],
+    /* Specify what JSX code is generated. */
+    "jsx": "react-jsx",
+
+    /* Specify what module code is generated. */
+    "module": "es2022",
+    /* Specify how TypeScript looks up a file from a given module specifier. */
+    "moduleResolution": "Bundler",
+    /* Enable importing .json files */
+    "resolveJsonModule": true,
+
+    /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */
+    "allowJs": true,
+    /* Enable error reporting in type-checked JavaScript files. */
+    "checkJs": false,
+
+    /* Disable emitting files from a compilation. */
+    "noEmit": true,
+
+    /* Ensure that each file can be safely transpiled without relying on other imports. */
+    "isolatedModules": true,
+    /* Allow 'import x from y' when a module doesn't have a default export. */
+    "allowSyntheticDefaultImports": true,
+    /* Ensure that casing is correct in imports. */
+    "forceConsistentCasingInFileNames": true,
+
+    /* Enable all strict type-checking options. */
+    "strict": true,
+
+    /* Skip type checking all .d.ts files. */
+    "skipLibCheck": true,
+    "types": ["@cloudflare/workers-types/experimental"]
+  },
+  "exclude": ["test"],
+  "include": ["src/**/*.ts"]
+}
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/vitest.config.mts b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/vitest.config.mts
new file mode 100644
index 000000000000..931e5113e0c2
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/vitest.config.mts
@@ -0,0 +1,11 @@
+import { defineWorkersConfig } from '@cloudflare/vitest-pool-workers/config';
+
+export default defineWorkersConfig({
+  test: {
+    poolOptions: {
+      workers: {
+        wrangler: { configPath: './wrangler.toml' },
+      },
+    },
+  },
+});
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-mcp/wrangler.toml b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/wrangler.toml
new file mode 100644
index 000000000000..69c10ce7cf01
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-mcp/wrangler.toml
@@ -0,0 +1,98 @@
+#:schema node_modules/wrangler/config-schema.json
+name = "cloudflare-mcp"
+main = "src/index.ts"
+compatibility_date = "2025-03-21"
+compatibility_flags = ["nodejs_compat"]
+
+# [vars]
+# E2E_TEST_DSN = ""
+
+# Automatically place your workloads in an optimal location to minimize latency.
+# If you are running back-end logic in a Worker, running it closer to your back-end infrastructure
+# rather than the end user may result in better performance.
+# Docs: https://developers.cloudflare.com/workers/configuration/smart-placement/#smart-placement
+# [placement]
+# mode = "smart"
+
+# Variable bindings. These are arbitrary, plaintext strings (similar to environment variables)
+# Docs:
+# - https://developers.cloudflare.com/workers/wrangler/configuration/#environment-variables
+# Note: Use secrets to store sensitive data.
+# - https://developers.cloudflare.com/workers/configuration/secrets/
+# [vars]
+# MY_VARIABLE = "production_value"
+
+# Bind the Workers AI model catalog. Run machine learning models, powered by serverless GPUs, on Cloudflare’s global network
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#workers-ai
+# [ai]
+# binding = "AI"
+
+# Bind an Analytics Engine dataset. Use Analytics Engine to write analytics within your Pages Function.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#analytics-engine-datasets
+# [[analytics_engine_datasets]]
+# binding = "MY_DATASET"
+
+# Bind a headless browser instance running on Cloudflare's global network.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#browser-rendering
+# [browser]
+# binding = "MY_BROWSER"
+
+# Bind a D1 database. D1 is Cloudflare’s native serverless SQL database.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#d1-databases
+# [[d1_databases]]
+# binding = "MY_DB"
+# database_name = "my-database"
+# database_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
+
+# Bind a dispatch namespace. Use Workers for Platforms to deploy serverless functions programmatically on behalf of your customers.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#dispatch-namespace-bindings-workers-for-platforms
+# [[dispatch_namespaces]]
+# binding = "MY_DISPATCHER"
+# namespace = "my-namespace"
+
+# Bind a Hyperdrive configuration. Use to accelerate access to your existing databases from Cloudflare Workers.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#hyperdrive
+# [[hyperdrive]]
+# binding = "MY_HYPERDRIVE"
+# id = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+
+# Bind a KV Namespace. Use KV as persistent storage for small key-value pairs.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#kv-namespaces
+# [[kv_namespaces]]
+# binding = "MY_KV_NAMESPACE"
+# id = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+
+# Bind an mTLS certificate. Use to present a client certificate when communicating with another service.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#mtls-certificates
+# [[mtls_certificates]]
+# binding = "MY_CERTIFICATE"
+# certificate_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
+
+# Bind a Queue producer. Use this binding to schedule an arbitrary task that may be processed later by a Queue consumer.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#queues
+# [[queues.producers]]
+# binding = "MY_QUEUE"
+# queue = "my-queue"
+
+# Bind a Queue consumer. Queue Consumers can retrieve tasks scheduled by Producers to act on them.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#queues
+# [[queues.consumers]]
+# queue = "my-queue"
+
+# Bind an R2 Bucket. Use R2 to store arbitrarily large blobs of data, such as files.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#r2-buckets
+# [[r2_buckets]]
+# binding = "MY_BUCKET"
+# bucket_name = "my-bucket"
+
+# Bind another Worker service. Use this binding to call another Worker without network overhead.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#service-bindings
+# [[services]]
+# binding = "MY_SERVICE"
+# service = "my-service"
+
+# Bind a Vectorize index. Use to store and query vector embeddings for semantic search, classification and other vector search use-cases.
+# Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#vectorize-indexes
+# [[vectorize]]
+# binding = "MY_INDEX"
+# index_name = "my-index"
diff --git a/packages/cloudflare/src/client.ts b/packages/cloudflare/src/client.ts
index 2de5147d3d5a..3332f71dab90 100644
--- a/packages/cloudflare/src/client.ts
+++ b/packages/cloudflare/src/client.ts
@@ -1,5 +1,6 @@
 import type { ClientOptions, Options, ServerRuntimeClientOptions } from '@sentry/core';
-import { applySdkMetadata, ServerRuntimeClient } from '@sentry/core';
+import { applySdkMetadata, debug, ServerRuntimeClient } from '@sentry/core';
+import { DEBUG_BUILD } from './debug-build';
 import type { makeFlushLock } from './flush';
 import type { CloudflareTransportOptions } from './transport';
 
@@ -11,6 +12,9 @@ import type { CloudflareTransportOptions } from './transport';
  */
 export class CloudflareClient extends ServerRuntimeClient {
   private readonly _flushLock: ReturnType<typeof makeFlushLock> | void;
+  private _pendingSpans: Set<string> = new Set();
+  private _spanCompletionPromise: Promise<void> | null = null;
+  private _resolveSpanCompletion: (() => void) | null = null;
 
   /**
    * Creates a new Cloudflare SDK instance.
@@ -31,12 +35,40 @@ export class CloudflareClient extends ServerRuntimeClient {
 
     super(clientOptions);
     this._flushLock = flushLock;
+
+    // Track span lifecycle to know when to flush
+    this.on('spanStart', span => {
+      const spanId = span.spanContext().spanId;
+      DEBUG_BUILD && debug.log('[CloudflareClient] Span started:', spanId);
+      this._pendingSpans.add(spanId);
+
+      if (!this._spanCompletionPromise) {
+        this._spanCompletionPromise = new Promise(resolve => {
+          this._resolveSpanCompletion = resolve;
+        });
+      }
+    });
+
+    this.on('spanEnd', span => {
+      const spanId = span.spanContext().spanId;
+      DEBUG_BUILD && debug.log('[CloudflareClient] Span ended:', spanId);
+      this._pendingSpans.delete(spanId);
+
+      // If no more pending spans, resolve the completion promise
+      if (this._pendingSpans.size === 0 && this._resolveSpanCompletion) {
+        DEBUG_BUILD && debug.log('[CloudflareClient] All spans completed, resolving promise');
+        this._resolveSpanCompletion();
+        this._resetSpanCompletionPromise();
+      }
+    });
   }
 
   /**
    * Flushes pending operations and ensures all data is processed.
    * If a timeout is provided, the operation will be completed within the specified time limit.
    *
+   * It will wait for all pending spans to complete before flushing.
+   *
    * @param {number} [timeout] - Optional timeout in milliseconds to force the completion of the flush operation.
    * @return {Promise<boolean>} A promise that resolves to a boolean indicating whether the flush operation was successful.
    */
@@ -44,8 +76,37 @@ export class CloudflareClient extends ServerRuntimeClient {
     if (this._flushLock) {
       await this._flushLock.finalize();
     }
+
+    if (this._pendingSpans.size > 0 && this._spanCompletionPromise) {
+      DEBUG_BUILD &&
+        debug.log('[CloudflareClient] Waiting for', this._pendingSpans.size, 'pending spans to complete...');
+
+      const timeoutMs = timeout ?? 5000;
+      const spanCompletionRace = Promise.race([
+        this._spanCompletionPromise,
+        new Promise(resolve =>
+          setTimeout(() => {
+            DEBUG_BUILD &&
+              debug.log('[CloudflareClient] Span completion timeout after', timeoutMs, 'ms, flushing anyway');
+            resolve(undefined);
+          }, timeoutMs),
+        ),
+      ]);
+
+      await spanCompletionRace;
+    }
+
     return super.flush(timeout);
   }
+
+  /**
+   * Resets the span completion promise and resolve function.
+   */
+  private _resetSpanCompletionPromise(): void {
+    this._pendingSpans.clear();
+    this._spanCompletionPromise = null;
+    this._resolveSpanCompletion = null;
+  }
 }
 
 interface BaseCloudflareOptions {