Agent Execution Timed Out in Agents Window (Windows) - new chats fail, only Open IDE works

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Frequent ERROR_EXTENSION_HOST_TIMEOUT in Agents Window on Windows.

Error toast: Agent Execution Timed Out / The agent execution provider did not respond in time. This may indicate the extension host is not running or is unresponsive.

Opening a new Agent session inside a project does NOT recover. The only workaround is Open IDE (classic editor + sidebar Agent). While Agents Window is stuck, Canvas also cannot be opened.

Request ID: 87261ea4-d07e-40be-a2bb-9c72c53a2f99

Cursor 3.18.9 (commit 2ba48ff3f7514cc4643c52ca9f7b3173d9b66130)
Windows 11 Home China 25H2 build 26200.9168
Install path: D:\cursor\

Steps:

  1. Open Agents Window on Windows
  2. Start or continue a local Agent chat (project or This PC)
  3. Send a message or try to open Canvas
  4. Wait 30-60s — timeout toast appears, spinner keeps running
  5. New session in the same project still times out
  6. Open IDE — sidebar Agent works

Expected: Agent in Agents Window initializes and replies.
Actual: Extension host never finishes starting; request never reaches servers.

Also seeing Timeout waiting for EverythingProvider (mcp.createClient) in local logs.

Related: Agent Execution Timed Out – Extension host becomes unresponsive frequently (Windows) and Cursor Agents from "Agent Window" don't work after v3.1.17 update

Steps to Reproduce

  1. On Windows, open Agents Window (not the classic IDE).
  2. Start or continue a local Agent chat in a project, or on “This PC”.
  3. Send a message, or try to open Canvas.
  4. Wait 30–60 seconds. The toast “Agent Execution Timed Out” appears; the spinner keeps running.
  5. Open a new Agent session in the same project — it still times out.
  6. Use Open IDE. Sidebar Agent works again. Canvas in Agents Window still fails while the host is stuck.

Operating System

Windows 10/11

Version Information

Cursor IDE: 3.18.9 (stable)
commit: 2ba48ff3f7514cc4643c52ca9f7b3173d9b66130
VS Code: 1.128.0
OS: Windows 11 Home China 25H2 (build 26200.9168)
Install: D:\cursor\

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

11

Hi @zhuyoujun, thanks for the detailed report.

I checked the logs associated with your account, and the component that runs agents inside the Agents Window is hanging during startup. Every startup attempt is being routed through a local proxy at 127.0.0.1:7897 (port 7897 usually belongs to a proxy client such as Clash, Clash Verge, or Mihomo), and that proxy is resetting the connections. Each attempt stalls for roughly 30 seconds before failing which matches the timeout you’re seeing exactly. Open IDE works because that window spins up a fresh instance of the component, so it’s a workaround rather than a real fix.

Two things to try:

  1. Fully quit Cursor (end Cursor.exe in Task Manager), then launch it once with --no-proxy-server. If agents work in the Agents Window, the proxy is confirmed as the cause.
  2. Either make sure your proxy client is running, listening on port 7897, and not resetting local connections (if you use TUN mode, try disabling it) or, if you don’t need the proxy, disable it and clear any reference to it from Cursor settings.

These two threads cover the same situation in more detail: