When task_system is enabled, the prompt said 'task tool: BLOCKED' which
LLMs interpreted as blocking task_create/task_update/task_list/task_get
too. Now the constraints section explicitly separates 'task (agent
delegation tool): BLOCKED' from 'task_create, task_update, ...: ALLOWED'
so Junior no longer refuses to use task management tools.
sisyphus-junior prompt always used todo-based discipline text regardless of
experimental.task_system setting because the useTaskSystem flag was never
forwarded from agent-config-handler to createSisyphusJuniorAgentWithOverrides.
