### Checklist - [x] I'm using the latest version of the extension ([see the latest version in the right column of this page](https://marketplace.visualstudio.com/items?itemName=GitLab.gitlab-workflow)) - Extension version: _latest_ - [x] I'm using the latest VS Code version ([find the latest version here](https://github.com/microsoft/vscode/releases)) - VS Code version: _VS Code Web (via Coder)_ - [x] I'm using a supported version of GitLab ([see README for the supported version](https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/blob/main/README.md#minimum-supported-version)) - GitLab version: _happens on `gitlab.com`_ ### Summary When using the GitLab Workflow VS Code extension in VS Code Web (accessed via Coder), the Duo Agentic Chat panel fails to load with an "Unable to connect to localhost" error page. Regular (non-agentic) Duo Chat works correctly in the same environment. The documented workaround `"gitlab.featureFlags.languageServerWebviews": false` fixes classic Duo Chat but does **NOT** fix Agentic Chat. This suggests the Agentic Chat webview (`/webview/agentic-duo-chat`) still relies on the LS-hosted HTTP server binding to `127.0.0.1` with no fallback for remote/browser-based environments. ### Root Cause Analysis The Language Server spins up a local HTTP server (e.g. `http://127.0.0.1:<port>/`). In VS Code Web, the browser runs locally but the extension host runs remotely, so `127.0.0.1` is unreachable from the browser context. Issues gitlab-vscode-extension#1944 and gitlab-vscode-extension#1943 fixed this for classic Duo Chat via: - gitlab-vscode-extension!2559 — disabled LS-hosted Chat webview in remote environments - gitlab-vscode-extension!2750 — fixed LS webviews in remote dev environments The Agentic Chat panel (`/webview/agentic-duo-chat` and `/webview/agentic-tabs`) appears to lack the same remote environment detection or fallback that was applied to classic Duo Chat. The `languageServerWebviews` feature flag toggle only affects the classic Chat webview, not the Agentic Chat webview. ### Steps to reproduce 1. Set up VS Code Web via Coder (or similar remote web-based VS Code environment) 2. Install the latest GitLab Workflow extension 3. Authenticate to a Duo-enabled GitLab namespace 4. Open the **GitLab Duo Agent Platform** panel 5. Observe that Agentic Chat shows an "Unable to connect to localhost" error page, while regular Duo Chat works correctly 6. Apply `"gitlab.featureFlags.languageServerWebviews": false` in settings and reload 7. Confirm regular Duo Chat still works, but **Agentic Chat still fails** with the same localhost error ### What is the current _bug_ behavior? Agentic Chat displays "Unable to connect to localhost" because it tries to load content from `http://127.0.0.1:<port>/webview/agentic-duo-chat`, which is unreachable in VS Code Web environments where the extension host runs remotely. The `languageServerWebviews` feature flag workaround does not apply to Agentic Chat — only to classic Duo Chat. ### What is the expected _correct_ behavior? Agentic Chat should load successfully in VS Code Web environments, consistent with how regular Duo Chat works after the gitlab-vscode-extension#1944 / gitlab-vscode-extension#1943 fixes. The remote environment detection and webview fallback logic should be extended to cover the Agentic Chat webview paths (`/webview/agentic-duo-chat` and `/webview/agentic-tabs`). ### Relevant logs and/or screenshots The browser attempts to connect to: ``` http://127.0.0.1:<port>/webview/agentic-duo-chat ``` This URL is not accessible because the HTTP server is running on the remote extension host, and the browser cannot reach `127.0.0.1` on the remote machine. ### Environment - **IDE**: VS Code Web (accessed via Coder) - **Extension version**: Latest - **GitLab instance**: GitLab.com - **Deployment type**: GitLab.com (SaaS) ### Possible fixes 1. Extend the remote environment detection logic (from gitlab-vscode-extension!2559 and gitlab-vscode-extension!2750) to also cover the Agentic Chat webview (`/webview/agentic-duo-chat` and `/webview/agentic-tabs`) 2. Ensure the `languageServerWebviews` feature flag (or an equivalent mechanism) also disables the LS-hosted HTTP server for Agentic Chat in remote environments 3. Use the VS Code [message passing API for dynamic webview content](https://code.visualstudio.com/api/advanced-topics/remote-extensions#use-the-message-passing-api-for-dynamic-webview-content) as recommended by VS Code documentation for remote-compatible webviews ### Related issues - https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/1944 — Duo Chat fails in VS Code Web (fixed for classic Chat) - https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/1943 — Duo Chat fails in VS Code Remote SSH (fixed for classic Chat) - https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/2145 — Duo Chat not available on VS Code Web (related, but covers classic Chat sidebar visibility)