## Problem Sessions that don't belong to a project have no link anywhere in GitLab. This covers group-level sessions, for example every session started from Slack through GitLab Duo for Slack. GitLab can already show these sessions. The page `/groups/<top-level-group>/-/automate/agent-sessions/<id>` renders them, but nothing builds that URL, so users can't get there. What this looks like today: - **Slack:** when Duo can't deliver an answer, it tells the user to "check the session in GitLab", but there is no link to click. - **Session page sidebar:** the session ID is a link for project sessions and plain text for group sessions. The sidebar also shows `Group: None` for a session that belongs to a group. - **API and MCP:** `web_url` is `null` for group sessions. ## What to do 1. **Build the URL for group sessions in one place.** `Gitlab::UrlBuilder#duo_workflow_url` ([`ee/lib/ee/gitlab/url_builder.rb`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/lib/ee/gitlab/url_builder.rb)) returns `nil` unless the session belongs to a project. For group sessions, return `/groups/<top-level-group>/-/automate/agent-sessions/<id>`. Use the top-level group, because the group page only works on top-level groups (`ensure_root_group` in `Groups::DuoAgentsPlatformController`). Sessions in a personal namespace have no page, so keep returning `nil` for them. 2. **Use that URL in the frontend.** These components build the link themselves from the project path, so they don't link group sessions: - `agent_flow_details_panel.vue`: the session ID in the sidebar - `agent_flow_details_overlay.vue` - `agent_flow_list_item.vue`: rows in the session list GraphQL already exposes `webUrl` on the session, backed by step 1. Switching to it fixes all three. 3. **Fix the sidebar's `Group: None`** for group sessions (optional, same area). 4. **Check the places that should then show a link without code changes.** They all use `workflow.web_url`: - **Slack:** the private session link (`post_session_link_ephemeral` in `Ai::Messaging::Adapters::Slack`) is skipped today because the URL is empty. The Slack error messages (`:no_response`, `:delivery_failed`) point users to the session. - **MCP:** `gitlab_start_duo_session` returns `web_url` (added in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/258011). That MR left group sessions without a URL. Check the response, and update the tool description and docs if they say group sessions have no URL. - **REST API** `web_url` (`API::Entities::Ai::DuoWorkflows::Workflow`) and **GraphQL** `webUrl`. - The Duo session email (`Emails::Ai::DuoWorkflows`), `duo_session_url` on notes (`EE::NoteEntity`), and the `@GitLabDuo` note reply link (`Ai::Messaging::Adapters::GitlabDuoNote`). 5. **Specs** for the URL builder (project, group, subgroup, personal namespace) and for the frontend components. <details> <summary>Context: how we got here</summary> **Starting point.** A Slack session on GitLab.com (session 8847015) never posted its final answer. The flow finished fine. Slack rejected the reply with `msg_too_long` because the message text sent alongside the answer was over Slack's 4,000-byte limit. All retries failed, and the user saw a spinner forever. Branch `fix/slack-duo-long-answer-delivery` fixes the delivery and tells the user when delivery fails. Its error message points to the session, which led us here: group sessions have no link. **The group page works.** Checked locally: - `Groups::DuoAgentsPlatformController` serves the agent platform app for any `automate/*` path on a top-level group, to any signed-in user. - The Vue router serves `/agent-sessions/:id` for groups as well as projects. - The session page loads the session by ID only (`getAgentFlow`, no project path). Access is checked on the session itself. - `/groups/gitlab-duo/-/automate/agent-sessions/3326`, a group-level `slack_assistant` session, rendered fully in GDK. **How to show the link in Slack (not decided yet).** Sessions are private to the person who started them, so a link shown to the whole channel would 404 for everyone else. Options we looked at: | Option | Only the user sees it | Stays after reload | |---|---|---| | Private message (`chat.postEphemeral`), today's approach | yes | no | | Button with `visible_to_user_ids` | yes | yes | | Overflow menu or small text link | no, others get a 404 | yes | | App Home tab listing recent sessions | yes | yes | Slack supports `visible_to_user_ids` on buttons and icon buttons. The approval card in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/258301 already uses it. The message footer (`context_actions`) only allows feedback buttons and icon buttons, and icon buttons currently only offer a trash icon with no URL, so a small private link in the footer isn't possible yet. Whichever option we pick, it needs the URL from this issue first. </details>