Agent Window fails in Dev Container with ERROR_EXTENSION_HOST_TIMEOUT, while normal Editor Window works

Evgenij_Zhukov · May 1, 2026, 10:02am

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
_waitForPushRequestContextProviderRegistration
streamFromAgentBackend / 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

deanrie · May 1, 2026, 10:24am

Hey, thanks for the detailed report. Your analysis is pretty much spot on.

This is a known limitation of Agent Window Glass. Dev Containers, same as WSL, are not in the list of remote extensions that Glass can start yet. So even after Install and Reload, the extension gets filtered out during scanning, the prompt loops, and the agent exec provider never registers. That is why you see ERROR_EXTENSION_HOST_TIMEOUT after 30 seconds. It is expected that Editor Window works in the same container because the allowlist does not apply there.

Workarounds for now:

Open the project in classic mode: cursor --classic
Or from the Glass window run the command Open Editor Window. This will open a classic window where Dev Containers resolve as usual

The team is rolling out remote support in Glass step by step. They started with SSH. Dev Containers are on the radar, but I do not have an ETA right now. If you want to follow the discussion, here is the canonical thread: Dev container remotes don't work with Glass. I will close this as a duplicate to keep the discussion in one place.

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Dev container remotes don't work with Glass Bug Reports extensions , ssh , devcontainers , agents-window	18	586	May 11, 2026
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Agent Window fails in Dev Container with ERROR_EXTENSION_HOST_TIMEOUT, while normal Editor Window works

Where does the bug appear (feature/product)?

Describe the Bug

Agent Window fails in Dev Container with ERROR_EXTENSION_HOST_TIMEOUT, while normal Editor Window works

Operating system

Summary

Request IDs

Error message

Steps to Reproduce

Expected Behavior

Operating System

Version Information

Additional Information

Evidence that Dev Container and remote agent extension work

Things already tried

1. Removed Copilot extensions from devcontainer config

2. Reinstalled Dev Containers extension locally

3. Cleaned stale Cursor worktrees

4. Disabled GitLens

Additional log observations

Error details (Agent Window)

Why this looks like a Cursor Agent Window bug

Does this stop you from using Cursor

Related topics