vitejs · sapphi-red · Mar 5, 2026 · Oct 9, 2025 · Oct 9, 2025 · Oct 9, 2025
diff --git a/docs/config/server-options.md b/docs/config/server-options.md
@@ -224,6 +224,44 @@ The error that appears in the Browser when the fallback happens can be ignored.
 
 :::
 
+## server.forwardConsole
+
+- **Type:** `boolean | { unhandledErrors?: boolean, logLevels?: ('error' | 'warn' | 'info' | 'log' | 'debug')[] }`
+- **Default:** auto (`true` when an AI coding agent is detected based on [`@vercel/detect-agent`](https://www.npmjs.com/package/@vercel/detect-agent), otherwise `false`)
+
+Forward browser runtime events to the Vite server console during development.
+
+- `true` enables forwarding unhandled errors and `console.error` / `console.warn` logs.
+- `unhandledErrors` controls forwarding uncaught exceptions and unhandled promise rejections.
+- `logLevels` controls which `console.*` calls are forwarded.
+
+For example:
+
+```js
+export default defineConfig({
+  server: {
+    forwardConsole: {
+      unhandledErrors: true,
+      logLevels: ['warn', 'error'],
+    },
+  },
+})
+```
+
+When unhandled errors are forwarded, they are logged in the server terminal with enhanced formatting, for example:
+
+```log
+1:18:38 AM [vite] (client) [Unhandled error] Error: this is test error
+ > testError src/main.ts:20:8
+     18|
+     19| function testError() {
+     20|   throw new Error('this is test error')
+       |        ^
+     21| }
+     22|
+ > HTMLButtonElement.<anonymous> src/main.ts:6:2
+```
+
 ## server.warmup
 
 - **Type:** `{ clientFiles?: string[], ssrFiles?: string[] }`

diff --git a/packages/vite/LICENSE.md b/packages/vite/LICENSE.md
@@ -25,7 +25,7 @@ SOFTWARE.
 
 # Licenses of bundled dependencies
 The published Vite artifact additionally contains code with the following licenses:
-BSD-2-Clause, CC0-1.0, ISC, MIT
+Apache-2.0, BSD-2-Clause, CC0-1.0, ISC, MIT
 
 # Bundled dependencies:
 ## @jridgewell/gen-mapping, @jridgewell/remapping, @jridgewell/sourcemap-codec, @jridgewell/trace-mapping
@@ -132,6 +132,243 @@ Repository: https://github.com/rollup/plugins
 
 ---------------------------------------
 
+## @vercel/detect-agent
+License: Apache-2.0
+By: Vercel
+Repository: https://github.com/vercel/vercel
+
+> Apache License
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+>       this License, without any additional terms or conditions.
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+>       names, trademarks, service marks, or product names of the Licensor,
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+> 
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+>       the Work or Derivative Works thereof, You may choose to offer,
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+>       on Your own behalf and on Your sole responsibility, not on behalf
+>       of any other Contributor, and only if You agree to indemnify,
+>       defend, and hold each Contributor harmless for any liability
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+>       of your accepting any such warranty or additional liability.
+> 
+>    END OF TERMS AND CONDITIONS
+> 
+>    APPENDIX: How to apply the Apache License to your work.
+> 
+>       To apply the Apache License to your work, attach the following
+>       boilerplate notice, with the fields enclosed by brackets "[]"
+>       replaced with your own identifying information. (Don't include
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+> 
+>    Copyright 2017 Vercel, Inc.
+> 
+>    Licensed under the Apache License, Version 2.0 (the "License");
+>    you may not use this file except in compliance with the License.
+>    You may obtain a copy of the License at
+> 
+>        http://www.apache.org/licenses/LICENSE-2.0
+> 
+>    Unless required by applicable law or agreed to in writing, software
+>    distributed under the License is distributed on an "AS IS" BASIS,
+>    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+>    See the License for the specific language governing permissions and
+>    limitations under the License.
+
+---------------------------------------
+
+## @vitest/utils
+License: MIT
+Repository: https://github.com/vitest-dev/vitest
+
+> MIT License
+> 
+> Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+> 
+> Permission is hereby granted, free of charge, to any person obtaining a copy
+> of this software and associated documentation files (the "Software"), to deal
+> in the Software without restriction, including without limitation the rights
+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+> copies of the Software, and to permit persons to whom the Software is
+> furnished to do so, subject to the following conditions:
+> 
+> The above copyright notice and this permission notice shall be included in all
+> copies or substantial portions of the Software.
+> 
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+> SOFTWARE.
+
+---------------------------------------
+
 ## anymatch
 License: ISC
 By: Elan Shanker

diff --git a/packages/vite/package.json b/packages/vite/package.json
@@ -92,8 +92,10 @@
     "@rollup/plugin-alias": "^6.0.0",
     "@rollup/plugin-dynamic-import-vars": "2.1.4",
     "@rollup/pluginutils": "^5.3.0",
+    "@vercel/detect-agent": "^1.1.0",
     "@types/escape-html": "^1.0.4",
     "@types/pnpapi": "^0.0.5",
+    "@vitest/utils": "4.1.0-beta.4",
     "@vitejs/devtools": "^0.0.0-alpha.31",
     "artichokie": "^0.4.2",
     "baseline-browser-mapping": "^2.9.19",

diff --git a/packages/vite/src/client/client.ts b/packages/vite/src/client/client.ts
@@ -10,6 +10,7 @@ import {
   normalizeModuleRunnerTransport,
 } from '../shared/moduleRunnerTransport'
 import { createHMRHandler } from '../shared/hmrHandler'
+import { setupForwardConsoleHandler } from '../shared/forwardConsole'
 import { ErrorOverlay, cspNonce, overlayId } from './overlay'
 import '@vite/env'
 
@@ -24,6 +25,7 @@ declare const __HMR_BASE__: string
 declare const __HMR_TIMEOUT__: number
 declare const __HMR_ENABLE_OVERLAY__: boolean
 declare const __WS_TOKEN__: string
+declare const __SERVER_FORWARD_CONSOLE__: any
 declare const __BUNDLED_DEV__: boolean
 
 console.debug('[vite] connecting...')
@@ -43,6 +45,7 @@ const base = __BASE__ || '/'
 const hmrTimeout = __HMR_TIMEOUT__
 const wsToken = __WS_TOKEN__
 const isBundleMode = __BUNDLED_DEV__
+const forwardConsole = __SERVER_FORWARD_CONSOLE__
 
 const transport = normalizeModuleRunnerTransport(
   (() => {
@@ -196,6 +199,8 @@ const hmrClient = new HMRClient(
 )
 transport.connect!(createHMRHandler(handleMessage))
 
+setupForwardConsoleHandler(transport, forwardConsole)
+
 async function handleMessage(payload: HotPayload) {
   switch (payload.type) {
     case 'connected':