The tab (a chat) is the context unit: two opencode tabs in one session are two independent agent contexts sharing one worktree. agent_sessions re-keys from (session_id, agent) to (chat_id, agent) — chat_id FK ON DELETE CASCADE (closing a tab ends its context); worktree_id and session_id become informational SET NULL columns. New worktrees table (one-per-session, survives session delete via session_id SET NULL) supersedes session_worktrees, which is defanged (CASCADE dropped) not yet removed. chat_id is threaded end-to-end: tasks.chat_id added, written by the coder message + skills routes from the frontend tab, read by runOpenCodeServerTask which falls back to resolve-or-create a chat for session-less creators (arena/MCP/new_task/generic) so ensureSession never gets a null key. Idempotent migration with a backfill-verify gate (0-row assertion after the test session was deleted). config_hash fingerprint logic preserved; one-worktree-per-session unchanged; runExternalAgent untouched. Column rename worktree_path -> path repointed at all five readers (server delete-guard, risk/stash endpoints, ensureSessionWorktree). Supersedes the earlier (worktree_id) draft.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Coder / menu now shows two groups: the active agent's commands first (manifest + live ACP available_commands), BooCoder skills second. SlashCommandPicker gains an opt-in groups prop (flat items path unchanged -> BooChat byte-identical, parity verified); ChatInput takes slashGroups; CoderPane builds the groups. Skills run under the selected agent: coder skill_invoke accepts a provider and, when external, injects the server-side skill body into a dispatched task instead of native inference. Also folds in the initial-chat skill fix (handleLandingSkill: create chat -> assign to pane -> invoke, same transition as a text send) that resolves the landing-page blank screen. BooChat slash menu + skill invocation unchanged.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
