Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
Agent Window fails in Dev Container with ERROR_EXTENSION_HOST_TIMEOUT, while normal Editor Window works
Operating system
Windows + WSL2 + Dev Container.
Windows version from winver: 22H2
Dev container environment observed in logs:
- Platform:
linux
- Arch:
x86_64
- Kernel:
6.6.87.2-microsoft-standard-WSL2
- Workspace path inside container:
/workspace
- Remote name:
dev-container
Summary
Agent Window cannot use a Dev Container workspace. It repeatedly shows:
Extension 'Dev Containers' is required to open the remote window. Do you want to install the extension?
Clicking Install and Reload does not fix it. After reload, the same prompt appears again.
If I send a prompt in Agent Window, it fails with ERROR_EXTENSION_HOST_TIMEOUT.
However, the same project works normally in a regular Cursor Editor Window opened inside the Dev Container. In that Editor Window, the remote Cursor server starts successfully, the extension host starts successfully, and anysphere.cursor-agent-exec activates successfully inside the Dev Container.
This looks isolated to Agent Window resolving/registering the Dev Containers remote execution provider.
Request IDs
Latest Request ID:
3d20e188-f7a5-43dd-8abe-ce08516688b0
Previous Request IDs with the same issue:
7c34178d-aa99-4afd-9ae7-b944a75e334e
974665e1-67a6-4249-87cd-4d75585ca654
Error message
ERROR_EXTENSION_HOST_TIMEOUT
Agent Execution Timed Out [deadline_exceeded]
The agent execution provider did not respond in time. This may indicate the extension host is not running or is unresponsive.
Stack trace:
ConnectError: [deadline_exceeded] Agent Execution Timed Out
at Zyy (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:38816:21732)
at oVh.waitForProviderRegistration (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:38816:24753)
at async mim._waitForPushRequestContextProviderRegistration (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:41817:4045)
at async mim.streamFromAgentBackend (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:41817:7626)
at async mim.getAgentStreamResponse (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:41817:19567)
at async hCt.submitChatMaybeAbortCurrent (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:29548:16906)
at async ORC.submitMessage (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:45410:99408)
at async I7C.submitMessage (vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:46428:17064)
at async vscode-file://vscode-app/c:/Users/evgen/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:43480:28443
Steps to Reproduce
- On Windows + WSL2, open a repository that has a .devcontainer/devcontainer.json.
- Open the project in Cursor using Dev Containers: Rebuild and Reopen in Container.
- Confirm the regular Editor Window works inside the Dev Container.
- Open Agent Window for the same workspace.
- Observe the prompt:
Extension 'Dev Containers' is required to open the remote window. Do you want to install the extension?
- Click Install and Reload.
- After reload, observe that the same prompt appears again.
- Send a prompt in Agent Window.
- Observe
ERROR_EXTENSION_HOST_TIMEOUT.
Expected Behavior
Agent Window should reuse or correctly open the same Dev Container remote context as the normal Editor Window, register the agent execution provider, and run normally.
Operating System
Windows 10/11
Version Information
Version: 3.2.16 (user setup)
VSCode Version: 1.105.1
Commit: 3e548838cf824b70851dd3ef27d0c6aae371b3f0
Date: 2026-04-28T21:07:47.682Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.19045
Additional Information
Evidence that Dev Container and remote agent extension work
From logs inside the Dev Container:
| Observation |
Detail |
| Remote name |
dev-container |
| Workspace paths |
["/workspace"] |
| Remote agent exec |
Extension activated success: anysphere.cursor-agent-exec — 4261 ms |
| Remote extension host |
Extension host with pid 33895 started |
| Remote server |
Extension host agent started. → Installing extensions... |
| Copilot |
No longer errors on github.copilot / github.copilot-chat after devcontainer change |
Things already tried
1. Removed Copilot extensions from devcontainer config
Previously .devcontainer/devcontainer.json included:
"GitHub.copilot",
"GitHub.copilot-chat"
They caused remote install errors:
Extension 'github.copilot' not found.
Extension 'github.copilot-chat' not found.
Error: Failed Installing Extensions: github.copilot, github.copilot-chat
Both entries were removed; Dev Container was rebuilt/reopened. Those errors disappeared, but Agent Window still fails.
Current relevant extensions list (no Copilot):
"extensions": [
"golang.go",
"dbaeumer.vscode-eslint",
"esbenp.prettier-vscode",
"ms-vscode.vscode-typescript-next",
"ms-azuretools.vscode-docker",
"ms-kubernetes-tools.vscode-kubernetes-tools",
"redhat.vscode-yaml",
"Tim-Koehler.helm-intellisense",
"zxh404.vscode-proto3",
"eamodio.gitlens",
"mhutchie.git-graph",
"humao.rest-client",
"yzhang.markdown-all-in-one",
"streetsidesoftware.code-spell-checker",
"PKief.material-icon-theme",
"enkia.tokyo-night",
"ms-vscode.makefile-tools",
"EditorConfig.EditorConfig"
]
2. Reinstalled Dev Containers extension locally
Commands run:
cursor --install-extension anysphere.remote-containers --force
Also cleared local cached remote container extensions and reinstalled:
Remove-Item -Recurse -Force "$env:USERPROFILE\.cursor\extensions\anysphere.remote-containers*" -ErrorAction SilentlyContinue
Remove-Item -Recurse -Force "$env:USERPROFILE\.cursor\extensions\ms-vscode-remote.remote-containers*" -ErrorAction SilentlyContinue
Result: Editor Window still opens the Dev Container correctly; Agent Window still shows the same Install and Reload prompt.
3. Cleaned stale Cursor worktrees
Stale Git worktrees pointed at Windows paths from inside the Linux repo, e.g.:
C:/Users/evgen/.cursor/worktrees/fast/...
Inside the container, git worktree list --porcelain showed prunable worktrees before cleanup.
Cleanup:
git worktree prune
On Windows:
Remove-Item -Recurse -Force "$env:USERPROFILE\.cursor\worktrees\fast" -ErrorAction SilentlyContinue
After: git worktree list inside the container shows only:
/workspace 8474e994 [chore/swarm-project-os-wiki]
Agent Window still fails.
4. Disabled GitLens
GitLens was disabled in the Dev Container and the window was reloaded.
Result: Agent Window still fails with the same error.
Latest Request ID (after disabling GitLens): 3d20e188-f7a5-43dd-8abe-ce08516688b0
Additional log observations
-
Earlier remote server showed:
Error getting extensions control manifest Timeout getting extensions control
After cleanup and rebuild, the remote agent and cursor-agent-exec still activate successfully in the normal Editor Window.
-
remoteexthost.log:
TypeError: Cannot read properties of null (reading 'elapsed')
at aGt.getStats
This appears after anysphere.cursor-agent-exec successfully activates; may be unrelated.
Error details (Agent Window)
Example client error:
{
"error": "ERROR_EXTENSION_HOST_TIMEOUT",
"details": {
"title": "Agent Execution Timed Out",
"detail": "The agent execution provider did not respond in time. This may indicate the extension host is not running or is unresponsive.",
"isRetryable": false,
"shouldShowImmediateError": true
}
}
Stack trace (minified) referenced:
waitForProviderRegistration_waitForPushRequestContextProviderRegistrationstreamFromAgentBackend / getAgentStreamResponse
Why this looks like a Cursor Agent Window bug
- Editor Window works in the Dev Container.
- Dev Containers resolver opens the project normally.
- Remote Cursor server starts; remote extension host starts.
anysphere.cursor-agent-exec activates successfully in the Dev Container.- Stale worktrees were cleaned.
- Copilot extension install errors were removed.
- GitLens was disabled.
- Agent Window still cannot register the execution provider and still asks to install Dev Containers.
Hypothesis: Agent Window does not correctly resolve or reuse the Dev Container remote context, or it uses a different extension/profile context where anysphere.remote-containers is not available—despite the main window working.
Does this stop you from using Cursor
No - Cursor works, but with this issue
may be useful to have the tooltip indicate that instead of prompting for an action that won’t fix it!
