diff --git a/src/main/apiServer/services/ProxyStreamService.ts b/src/main/apiServer/services/ProxyStreamService.ts
index 5519dc49ef..90149a617e 100644
--- a/src/main/apiServer/services/ProxyStreamService.ts
+++ b/src/main/apiServer/services/ProxyStreamService.ts
@@ -33,6 +33,8 @@ import type { Response } from 'express'
 
 import type { InputFormat, InputParamsMap, IStreamAdapter } from '../adapters'
 import { MessageConverterFactory, type OutputFormat, StreamAdapterFactory } from '../adapters'
+import { LONG_POLL_TIMEOUT_MS } from '../config/timeouts'
+import { createStreamAbortController } from '../utils/createStreamAbortController'
 import { googleReasoningCache, openRouterReasoningCache } from './reasoning-cache'
 
 const logger = loggerService.withContext('ProxyStreamService')
@@ -96,6 +98,7 @@ interface ExecuteStreamConfig {
   outputFormat: OutputFormat
   middlewares?: LanguageModelMiddleware[]
   plugins?: AiPlugin[]
+  abortSignal?: AbortSignal
 }
 
 // ============================================================================
@@ -248,7 +251,7 @@ async function executeStream(config: ExecuteStreamConfig): Promise<{
   adapter: IStreamAdapter
   outputStream: ReadableStream<unknown>
 }> {
-  const { provider, modelId, params, inputFormat, outputFormat, middlewares = [], plugins = [] } = config
+  const { provider, modelId, params, inputFormat, outputFormat, middlewares = [], plugins = [], abortSignal } = config
 
   // Convert provider config to AI SDK config
   let sdkConfig = providerToAiSdkConfig(provider, modelId)
@@ -291,7 +294,8 @@ async function executeStream(config: ExecuteStreamConfig): Promise<{
     stopWhen: stepCountIs(100),
     headers: defaultAppHeaders(),
     tools,
-    providerOptions
+    providerOptions,
+    abortSignal
   })
 
   // Transform stream using adapter
@@ -344,6 +348,21 @@ export async function streamToResponse(config: StreamConfig): Promise<void> {
     pluginCount: plugins.length
   })
 
+  // Create abort controller for client disconnect handling
+  const streamController = createStreamAbortController({
+    timeoutMs: LONG_POLL_TIMEOUT_MS
+  })
+  const { abortController, dispose } = streamController
+
+  // Handle client disconnect
+  const handleDisconnect = () => {
+    if (abortController.signal.aborted) return
+    logger.info('Client disconnected, aborting stream', { providerId: provider.id, modelId })
+    abortController.abort('Client disconnected')
+  }
+
+  response.on('close', handleDisconnect)
+
   try {
     // Set SSE headers
     response.setHeader('Content-Type', 'text/event-stream')
@@ -358,7 +377,8 @@ export async function streamToResponse(config: StreamConfig): Promise<void> {
       inputFormat,
       outputFormat,
       middlewares,
-      plugins
+      plugins,
+      abortSignal: abortController.signal
     })
 
     // Get formatter for the output format
@@ -370,6 +390,7 @@ export async function streamToResponse(config: StreamConfig): Promise<void> {
       while (true) {
         const { done, value } = await reader.read()
         if (done) break
+        if (response.writableEnded) break
         response.write(formatter.formatEvent(value))
       }
     } finally {
@@ -377,8 +398,10 @@ export async function streamToResponse(config: StreamConfig): Promise<void> {
     }
 
     // Send done marker and end response
-    response.write(formatter.formatDone())
-    response.end()
+    if (!response.writableEnded) {
+      response.write(formatter.formatDone())
+      response.end()
+    }
 
     logger.info('Proxy stream completed', { providerId: provider.id, modelId })
     onComplete?.()
@@ -386,6 +409,9 @@ export async function streamToResponse(config: StreamConfig): Promise<void> {
     logger.error('Error in proxy stream', error as Error, { providerId: provider.id, modelId })
     onError?.(error)
     throw error
+  } finally {
+    response.off('close', handleDisconnect)
+    dispose()
   }
 }