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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.

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Choose the right browser mode first

You have two valid patterns:

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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

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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.

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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

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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.

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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.

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Validate in layers

Work top to bottom. Do not skip ahead.

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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.

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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.

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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

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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:

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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

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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

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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?

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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