diff --git a/.changeset/fix-vscode-server-auth.md b/.changeset/fix-vscode-server-auth.md
new file mode 100644
index 0000000000..0b3d11a994
--- /dev/null
+++ b/.changeset/fix-vscode-server-auth.md
@@ -0,0 +1,7 @@
+---
+"cline": patch
+---
+
+fix: use vscode.env.openExternal for auth in remote environments
+
+Fixes OAuth authentication in VS Code Server and remote environments by routing browser URL opening through VS Code's native openExternal API instead of the npm 'open' package.
diff --git a/cli/src/acp/ACPHostBridgeClientProvider.ts b/cli/src/acp/ACPHostBridgeClientProvider.ts
index e487d62aa8..5ed3acc284 100644
--- a/cli/src/acp/ACPHostBridgeClientProvider.ts
+++ b/cli/src/acp/ACPHostBridgeClientProvider.ts
@@ -172,6 +172,16 @@ class ACPEnvServiceClient implements EnvServiceClientInterface {
 		Logger.debug("[ACPEnvServiceClient] shutdown called (stub)")
 		return proto.cline.Empty.create()
 	}
+
+	async openExternal(request: proto.cline.StringRequest): Promise<proto.cline.Empty> {
+		const url = request.value || ""
+		if (url) {
+			Logger.debug(`[ACPEnvServiceClient] openExternal: ${url}`)
+			const { openUrlInBrowser } = await import("../utils/browser")
+			await openUrlInBrowser(url)
+		}
+		return proto.cline.Empty.create()
+	}
 }
 
 /**
diff --git a/cli/src/controllers/index.ts b/cli/src/controllers/index.ts
index 2ea5ebc277..cae16efe13 100644
--- a/cli/src/controllers/index.ts
+++ b/cli/src/controllers/index.ts
@@ -142,6 +142,17 @@ export class CliEnvServiceClient implements EnvServiceClientInterface {
 		printInfo("Shutting down...")
 		return proto.cline.Empty.create()
 	}
+
+	async openExternal(request: proto.cline.StringRequest): Promise<proto.cline.Empty> {
+		const url = request.value || ""
+		if (url) {
+			printInfo(`🌐 Opening: ${url}`)
+			// Dynamically import 'open' to open URL in default browser
+			const { default: open } = await import("open")
+			await open(url)
+		}
+		return proto.cline.Empty.create()
+	}
 }
 
 /**
diff --git a/cli/src/utils/browser.ts b/cli/src/utils/browser.ts
new file mode 100644
index 0000000000..3e10aee231
--- /dev/null
+++ b/cli/src/utils/browser.ts
@@ -0,0 +1,10 @@
+/**
+ * Opens a URL in the user's default browser.
+ * Uses dynamic import of the 'open' package to open URLs.
+ *
+ * @param url - The URL to open in the browser
+ */
+export async function openUrlInBrowser(url: string): Promise<void> {
+	const { default: open } = await import("open")
+	await open(url)
+}
diff --git a/proto/host/env.proto b/proto/host/env.proto
index a8e234964f..2c5a229448 100644
--- a/proto/host/env.proto
+++ b/proto/host/env.proto
@@ -36,6 +36,11 @@ service EnvService {
 
   // Logs a debug message to the host environment's log/output console.
   rpc debugLog(cline.StringRequest) returns (cline.Empty);
+
+  // Opens an external URL in the default browser.
+  // In remote environments (VS Code Server, SSH, etc.), this routes the URL
+  // to the user's local machine to open in their local browser.
+  rpc openExternal(cline.StringRequest) returns (cline.Empty);
 }
 
 message GetHostVersionResponse {
diff --git a/src/hosts/vscode/hostbridge/env/openExternal.ts b/src/hosts/vscode/hostbridge/env/openExternal.ts
new file mode 100644
index 0000000000..d3c6841a3f
--- /dev/null
+++ b/src/hosts/vscode/hostbridge/env/openExternal.ts
@@ -0,0 +1,8 @@
+import { Empty, StringRequest } from "@shared/proto/cline/common"
+import * as vscode from "vscode"
+
+export async function openExternal(request: StringRequest): Promise<Empty> {
+	const uri = vscode.Uri.parse(request.value)
+	await vscode.env.openExternal(uri) // ← Routes to local browser in remote setups!
+	return Empty.create({})
+}
diff --git a/src/utils/env.ts b/src/utils/env.ts
index d6cc50a180..682b77de48 100644
--- a/src/utils/env.ts
+++ b/src/utils/env.ts
@@ -1,5 +1,4 @@
 import { EmptyRequest, StringRequest } from "@shared/proto/cline/common"
-import open from "open"
 import { HostProvider } from "@/hosts/host-provider"
 import { Logger } from "@/shared/services/Logger"
 
@@ -41,5 +40,6 @@ export async function readTextFromClipboard(): Promise<string> {
  */
 export async function openExternal(url: string): Promise<void> {
 	Logger.log("Opening browser:", url)
-	await open(url)
+	// Use VS Code's openExternal which handles remote environments
+	await HostProvider.env.openExternal(StringRequest.create({ value: url }))
 }