Test: AH Copilot SDK network proxy

[chrmarti]

Refs: #324209

• macOS @pierceboggan
• linux @aeschli
• windows @TylerLeonhardt

Complexity: 4

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Test: Agent Host respects HTTP proxy configuration

Verify that chat requests made from the Agent Host process honor the configured HTTP proxy, both when the proxy is set explicitly via the http.proxy setting and when it is resolved from the OS (PAC URL).

Two windows: the test proxy runs inside a dev container in one VS Code window (the "proxy window"). The actual testing happens in a separate VS Code window/install (the "test window") — it is easier to use two different installs (e.g. run the dev container in VS Code Stable and test in VS Code Insiders). Steps below that mention Settings, restarting, and making chat requests apply to the test window.

Setup

1. In the proxy window, start the test proxy from the vscode-proxy-agent repo:
   • Clone https://github.com/microsoft/vscode-proxy-agent.
   • Important: switch to branch chrmarti/quarrelsome-gibbon.
   • Dev Containers: Reopen in Container > HTTP Proxy Test.
   • This starts 3 log terminals in the dev container: 1 for the PAC config and 2 for the two proxies. (See .devcontainer/http-proxy-test/README.md for details.)
   • Keep the proxy log terminals visible so you can observe requests as they arrive.
2. In the test window, ensure the Agent Host is enabled: set chat.agentHost.enabled to true in Settings.

Test 1: Explicit http.proxy setting

1. Set http.proxy in Settings to the test proxy, e.g. http://127.0.0.1:3155.
2. Restart VS Code (current limitation: the Agent Host does not pick up proxy changes without a restart).
3. Make a chat request that runs in the Agent Host's Copilot.
4. Verify in the proxy log terminal that the chat request(s) go through the proxy.

Test 2: PAC URL configured in the OS

1. Remove the http.proxy setting.
2. Configure the PAC URL at the OS level, pointing at the test PAC, e.g. http://127.0.0.1:4444:
   • macOS: System Settings → Network → (active interface) → Details… → Proxies → enable "Automatic proxy configuration" and set the URL.
   • Windows: Settings → Network & Internet → Proxy → "Use setup script" → turn on and set the "Script address".
   • Linux (GNOME): Settings → Network → Network Proxy → set Method to "Automatic" and set the "Configuration URL".
3. Restart VS Code (current limitation, as above).
4. Make a chat request that runs in the Agent Host's Copilot.
5. Verify in the proxy log terminal that the chat request(s) go through the proxy resolved from the PAC file.

Cleanup

1. Remove the http.proxy setting if it is still set.
2. Remove the OS-level PAC URL / automatic proxy configuration.
3. Restart VS Code so it no longer routes traffic through the test proxy.

[aeschli]

• to start the 3 log terminals I has to run the build task in the dev container

Tested on Ubuntu 22.04, all worked, I could see the traffic going through the proxies.

[amunger]

"Use setup script" → turn on and set the "Script address".

Do I set this to http://127.0.0.1:3155? this seems to make my internet connection stop working. Also, should I restart WSL as it tells me to do after setting this? That causes the error: (though I can still launch the dev container)

PS C:\Windows\System32> wsl --shutdown
PS C:\Windows\System32> wsl
wsl: A localhost proxy configuration was detected but not mirrored into WSL. WSL in NAT mode does not support localhost proxies.

[amunger]

should I be using a chat session for the dev container window? the chat pane never finishes loading in that case (I can't send a request), there are no models to select, and AH copilot doesn't show up in the list:

and in a local window, the chat pane loads, but has an error when I try to send, probably because setting the proxy on Windows kills my internet:

ah-logs-greeting.zip

[pierceboggan]

I'm hitting the same as @amunger did above. The Chat window is unresponsive to sending any messages once the proxy is configured.