diff --git a/src/server/__tests__/proxy-network-settings.test.ts b/src/server/__tests__/proxy-network-settings.test.ts
index 43a19e02..7845ac50 100644
--- a/src/server/__tests__/proxy-network-settings.test.ts
+++ b/src/server/__tests__/proxy-network-settings.test.ts
@@ -30,6 +30,156 @@ describe('proxy network settings', () => {
   beforeEach(setup)
   afterEach(teardown)
 
+  test('uses configured AI request timeout for non-stream upstream requests', async () => {
+    await fs.writeFile(
+      path.join(tmpDir, 'settings.json'),
+      JSON.stringify({
+        network: {
+          aiRequestTimeoutMs: 45_000,
+          proxy: { mode: 'system', url: '' },
+        },
+      }),
+      'utf-8',
+    )
+
+    const svc = new ProviderService()
+    const provider = await svc.addProvider({
+      presetId: 'custom',
+      name: 'OpenAI Proxy',
+      baseUrl: 'https://api.example.com',
+      apiKey: 'sk-test',
+      apiFormat: 'openai_chat',
+      models: {
+        main: 'model-main',
+        haiku: 'model-main',
+        sonnet: 'model-main',
+        opus: 'model-main',
+      },
+    })
+
+    const originalFetch = globalThis.fetch
+    const originalTimeout = AbortSignal.timeout
+    const timeoutCalls: number[] = []
+    globalThis.fetch = mock(async (_url: string | URL | Request, _init?: RequestInit) => {
+      return new Response(JSON.stringify({
+        id: 'chatcmpl-network-timeout',
+        object: 'chat.completion',
+        created: 0,
+        model: 'model-main',
+        choices: [{
+          index: 0,
+          message: { role: 'assistant', content: 'ok' },
+          finish_reason: 'stop',
+        }],
+        usage: { prompt_tokens: 1, completion_tokens: 1, total_tokens: 2 },
+      }), {
+        status: 200,
+        headers: { 'Content-Type': 'application/json' },
+      })
+    }) as typeof fetch
+    AbortSignal.timeout = ((ms: number) => {
+      timeoutCalls.push(ms)
+      return originalTimeout(ms)
+    }) as typeof AbortSignal.timeout
+
+    try {
+      const body = {
+        model: 'model-main',
+        max_tokens: 64,
+        messages: [{ role: 'user', content: 'hello' }],
+      }
+      const req = new Request(
+        `http://localhost:3456/proxy/providers/${provider.id}/v1/messages`,
+        {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify(body),
+        },
+      )
+      const res = await handleProxyRequest(req, new URL(req.url))
+
+      expect(res.status).toBe(200)
+      expect(timeoutCalls).toEqual([45_000])
+    } finally {
+      AbortSignal.timeout = originalTimeout
+      globalThis.fetch = originalFetch
+    }
+  })
+
+  test('uses configured AI request timeout for non-stream Responses upstream requests', async () => {
+    await fs.writeFile(
+      path.join(tmpDir, 'settings.json'),
+      JSON.stringify({
+        network: {
+          aiRequestTimeoutMs: 45_000,
+          proxy: { mode: 'system', url: '' },
+        },
+      }),
+      'utf-8',
+    )
+
+    const svc = new ProviderService()
+    const provider = await svc.addProvider({
+      presetId: 'custom',
+      name: 'OpenAI Responses Proxy',
+      baseUrl: 'https://api.example.com',
+      apiKey: 'sk-test',
+      apiFormat: 'openai_responses',
+      models: {
+        main: 'model-main',
+        haiku: 'model-main',
+        sonnet: 'model-main',
+        opus: 'model-main',
+      },
+    })
+
+    const originalFetch = globalThis.fetch
+    const originalTimeout = AbortSignal.timeout
+    const timeoutCalls: number[] = []
+    globalThis.fetch = mock(async (_url: string | URL | Request, _init?: RequestInit) => {
+      return new Response(JSON.stringify({
+        id: 'resp-network-timeout',
+        status: 'completed',
+        model: 'model-main',
+        output: [{
+          type: 'message',
+          content: [{ type: 'output_text', text: 'ok' }],
+        }],
+        usage: { input_tokens: 1, output_tokens: 1 },
+      }), {
+        status: 200,
+        headers: { 'Content-Type': 'application/json' },
+      })
+    }) as typeof fetch
+    AbortSignal.timeout = ((ms: number) => {
+      timeoutCalls.push(ms)
+      return originalTimeout(ms)
+    }) as typeof AbortSignal.timeout
+
+    try {
+      const body = {
+        model: 'model-main',
+        max_tokens: 64,
+        messages: [{ role: 'user', content: 'hello' }],
+      }
+      const req = new Request(
+        `http://localhost:3456/proxy/providers/${provider.id}/v1/messages`,
+        {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify(body),
+        },
+      )
+      const res = await handleProxyRequest(req, new URL(req.url))
+
+      expect(res.status).toBe(200)
+      expect(timeoutCalls).toEqual([45_000])
+    } finally {
+      AbortSignal.timeout = originalTimeout
+      globalThis.fetch = originalFetch
+    }
+  })
+
   test('uses configured AI request timeout for streaming upstream requests', async () => {
     await fs.writeFile(
       path.join(tmpDir, 'settings.json'),
diff --git a/src/server/proxy/handler.ts b/src/server/proxy/handler.ts
index 523bf0ab..1d9dc546 100644
--- a/src/server/proxy/handler.ts
+++ b/src/server/proxy/handler.ts
@@ -134,7 +134,7 @@ async function handleOpenaiChat(
       Authorization: `Bearer ${apiKey}`,
     },
     body: signClaudeCodeCCHInTransformedString(JSON.stringify(transformed)),
-    signal: AbortSignal.timeout(isStream ? aiRequestTimeoutMs : Math.max(aiRequestTimeoutMs, 300_000)),
+    signal: AbortSignal.timeout(aiRequestTimeoutMs),
     ...proxyOptions,
   })
 
@@ -202,7 +202,7 @@ async function handleOpenaiResponses(
       Authorization: `Bearer ${apiKey}`,
     },
     body: signClaudeCodeCCHInTransformedString(JSON.stringify(transformed)),
-    signal: AbortSignal.timeout(isStream ? aiRequestTimeoutMs : Math.max(aiRequestTimeoutMs, 300_000)),
+    signal: AbortSignal.timeout(aiRequestTimeoutMs),
     ...proxyOptions,
   })