WSL2 + Windows + remote Chrome CDP troubleshooting

WSL2 + Windows + remote Chrome CDP troubleshooting

This guide covers the common split-host setup where:

• OpenClaw Gateway runs inside WSL2
• Chrome runs on Windows
• browser control must cross the WSL2/Windows boundary

It also covers the layered failure pattern from issue #39369: several independent problems can show up at once, which makes the wrong layer look broken first.

Choose the right browser mode first

You have two valid patterns:

Option 1: Raw remote CDP from WSL2 to Windows

Use a remote browser profile that points from WSL2 to a Windows Chrome CDP endpoint.

Choose this when:

• the Gateway stays inside WSL2
• Chrome runs on Windows
• you need browser control to cross the WSL2/Windows boundary

Option 2: Host-local Chrome MCP

Use existing-session / user only when the Gateway itself runs on the same host as Chrome.

Choose this when:

• OpenClaw and Chrome are on the same machine
• you want the local signed-in browser state
• you do not need cross-host browser transport

For WSL2 Gateway + Windows Chrome, prefer raw remote CDP. Chrome MCP is host-local, not a WSL2-to-Windows bridge.

Working architecture

Reference shape:

• WSL2 runs the Gateway on 127.0.0.1:18789
• Windows opens the Control UI in a normal browser at http://127.0.0.1:18789/
• Windows Chrome exposes a CDP endpoint on port 9222
• WSL2 can reach that Windows CDP endpoint
• OpenClaw points a browser profile at the address that is reachable from WSL2

Why this setup is confusing

Several failures can overlap:

• WSL2 cannot reach the Windows CDP endpoint
• the Control UI is opened from a non-secure origin
• gateway.controlUi.allowedOrigins does not match the page origin
• token or pairing is missing
• the browser profile points at the wrong address

Because of that, fixing one layer can still leave a different error visible.

Critical rule for the Control UI

When the UI is opened from Windows, use Windows localhost unless you have a deliberate HTTPS setup.

Use:

http://127.0.0.1:18789/

Do not default to a LAN IP for the Control UI. Plain HTTP on a LAN or tailnet address can trigger insecure-origin/device-auth behavior that is unrelated to CDP itself. See Control UI.

Validate in layers

Work top to bottom. Do not skip ahead.

Layer 1: Verify Chrome is serving CDP on Windows

Start Chrome on Windows with remote debugging enabled:

chrome.exe --remote-debugging-port=9222

From Windows, verify Chrome itself first:

curl http://127.0.0.1:9222/json/version
curl http://127.0.0.1:9222/json/list

If this fails on Windows, OpenClaw is not the problem yet.

Layer 2: Verify WSL2 can reach that Windows endpoint

From WSL2, test the exact address you plan to use in cdpUrl:

curl http://WINDOWS_HOST_OR_IP:9222/json/version
curl http://WINDOWS_HOST_OR_IP:9222/json/list

Good result:

• /json/version returns JSON with Browser / Protocol-Version metadata
• /json/list returns JSON (empty array is fine if no pages are open)

If this fails:

• Windows is not exposing the port to WSL2 yet
• the address is wrong for the WSL2 side
• firewall / port forwarding / local proxying is still missing

Fix that before touching OpenClaw config.

Layer 3: Configure the correct browser profile

For raw remote CDP, point OpenClaw at the address that is reachable from WSL2:

{
  browser: {
    enabled: true,
    defaultProfile: "remote",
    profiles: {
      remote: {
        cdpUrl: "http://WINDOWS_HOST_OR_IP:9222",
        attachOnly: true,
        color: "#00AA00",
      },
    },
  },
}

Notes:

• use the WSL2-reachable address, not whatever only works on Windows
• keep attachOnly: true for externally managed browsers
• test the same URL with curl before expecting OpenClaw to succeed

Layer 4: Verify the Control UI layer separately

Open the UI from Windows:

http://127.0.0.1:18789/

Then verify:

• the page origin matches what gateway.controlUi.allowedOrigins expects
• token auth or pairing is configured correctly
• you are not debugging a Control UI auth problem as if it were a browser problem

Helpful page:

• Control UI

Layer 5: Verify end-to-end browser control

From WSL2:

openclaw browser open https://example.com --browser-profile remote
openclaw browser tabs --browser-profile remote

Good result:

• the tab opens in Windows Chrome
• openclaw browser tabs returns the target
• later actions (snapshot, screenshot, navigate) work from the same profile

Common misleading errors

Treat each message as a layer-specific clue:

• control-ui-insecure-auth
  • UI origin / secure-context problem, not a CDP transport problem
• token_missing
  • auth configuration problem
• pairing required
  • device approval problem
• Remote CDP for profile "remote" is not reachable
  • WSL2 cannot reach the configured cdpUrl
• gateway timeout after 1500ms
  • often still CDP reachability or a slow/unreachable remote endpoint
• No Chrome tabs found for profile="user"
  • local Chrome MCP profile selected where no host-local tabs are available

Fast triage checklist

1. Windows: does curl http://127.0.0.1:9222/json/version work?
2. WSL2: does curl http://WINDOWS_HOST_OR_IP:9222/json/version work?
3. OpenClaw config: does browser.profiles.<name>.cdpUrl use that exact WSL2-reachable address?
4. Control UI: are you opening http://127.0.0.1:18789/ instead of a LAN IP?
5. Are you trying to use existing-session across WSL2 and Windows instead of raw remote CDP?

Practical takeaway

The setup is usually viable. The hard part is that browser transport, Control UI origin security, and token/pairing can each fail independently while looking similar from the user side.

When in doubt:

• verify the Windows Chrome endpoint locally first
• verify the same endpoint from WSL2 second
• only then debug OpenClaw config or Control UI auth