The PATCH /api/kanban/tasks/:id endpoint allowed any status-to-any-status
transition for the non-claim/complete/block/archive set via raw
`UPDATE tasks SET status = ?`. This let UI users (or any client) flip a
task to 'running' without going through kb.claim_task(), bypassing
claim_lock + claim_expires + started_at + worker_pid. The dispatcher
treats such a phantom-claimed task as orphaned and may reclaim, hide, or
double-dispatch it.
Match the agent dashboard plugin's contract
(plugins/kanban/dashboard/plugin_api.py update_task):
- status='running' via PATCH → ValueError (HTTP 400)
- status='ready' from currently-blocked → kb.unblock_task() (fires
'unblocked' event)
- status='ready' from anything else, plus status in {'todo', 'triage'}
→ new _set_status_direct() helper that nulls claim fields when leaving
'running', closes any active run with outcome='reclaimed', and
appends a 'status' event row to task_events
- status='done', 'blocked', 'archived' → unchanged (already structured)
Frontend changes:
- Drop 'running' from the .kanban-status-actions button row in the task
detail pane (clicking it would always 400 anyway).
- allowKanbanDrop() refuses the 'running' column as a drop target with
dropEffect='none' so users see immediate visual feedback that the
dispatcher/claim path owns running.
Tests added (3, all passing):
- test_patch_status_running_is_rejected_to_protect_dispatcher_contract
- test_patch_status_done_to_running_is_rejected
- test_patch_status_blocked_to_ready_routes_through_unblock_task
Existing 12 tests still pass.
Co-authored-by: ai-ag2026 <ai-ag2026@users.noreply.github.com>
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