Expose subagent sessions, status, and results in the Android UI

[Qiiks]

Summary

OpenCode Mobile does not currently expose subagents as a first-class part of a session. A parent session may run subagents through the task tool, but the mobile UI does not provide a visible subagent list, live status, result/error view, or navigation into the child session. This makes a major part of an OpenCode/OMO workflow invisible from Android.

Current behavior

• The transcript can show a task tool card, but that is not enough to monitor the child session.
• The session list intentionally requests root sessions only (roots=true), so child sessions with parentID are filtered out.
• The mobile SDK currently exposes session list/get/messages/prompt operations but no child-session retrieval/navigation method.
• There is no obvious way to see which subagents are running, completed, failed, or waiting for input.

Expected behavior

For a parent session that launches subagents, provide a clear Subagents/Children section or equivalent that:

1. Lists child sessions associated with the parent.
2. Shows each subagent's name/role, status, model if available, start/completion state, and errors.
3. Updates while the parent and child sessions are running.
4. Allows tapping a child to inspect its transcript, tool calls, and final result.
5. Makes nested subagents navigable without losing the parent session context.
6. Preserves the current root-session list behavior while making child sessions discoverable in the parent detail screen.

Suggested implementation direction

Use the server's child-session relationship (parentID / the session children endpoint where available) and the existing SSE event stream rather than treating the task tool card as the complete source of truth. Older servers should degrade gracefully when the child-session endpoint is unavailable.

Environment

• Client: OpenCode Mobile for Android
• OpenCode server: 1.18.18, Qiiks/opencode release v1.18.18-orw.1
• OMO workflow: subagent delegation through task/completion reminders
• Device / Android version / app version: please add exact values when reproducing