Scope note — why there are no trees on a site about subtask structure: subagenttasks.com's schema really does have a task_dependencies table (its migrations/0001_init.sql, generalized from the real TaskCreate tool's addBlocks/addBlockedBy params), and its own HTML task-detail pages join it server-side for blocks/blocked-by lists. But the public JSON API this site reads — GET /api/tasks and GET /api/tasks/:id — does not expose any dependency edges: no row in the live response carries a dependency field, and the upstream's own llms.txt lists no dependencies endpoint (verified by fetching both, 2026-07-09). Rather than invent edges, this page groups the real rows by session_id — the one grouping structure the API actually exposes — and links each task and session back to the upstream, where the dependency joins live.