Set Session

Binds the current Claude Code session to a Linear ticket for cross-session correlation.

Behavior

1. Accept a ticket ID argument (e.g., /onex:set_session PROJ-1234)
2. Write task_id: PROJ-1234 to .onex_state/active_session.yaml (authoritative binding per Doctrine D1)
3. Set ONEX_TASK_ID=PROJ-1234 in the process environment as a derived runtime convenience
4. Emit a session.status_changed event with task_id and status: bound
5. Confirm: "Session bound to PROJ-1234. All events will carry this task_id."

Implementation

Use the TaskBinding service from omniclaude.services.task_binding:

from omniclaude.services.task_binding import TaskBinding

binding = TaskBinding()

# Check for --clear flag
if args == "--clear":
    binding.clear()
    # Emit session.status_changed with status: unbound
    print("Session unbound. Events will no longer carry a task_id.")
else:
    # Check for existing binding
    existing = binding.detect_existing()
    if existing and existing != task_id:
        print(f"Replacing existing binding to {existing}.")

    binding.bind(task_id)
    # Emit session.status_changed with status: bound
    print(f"Session bound to {task_id}. All events will carry this task_id.")

Unbinding

/onex:set_session --clear removes the binding:

1. Remove .onex_state/active_session.yaml
2. Unset ONEX_TASK_ID from the process environment
3. Emit session.status_changed with status: unbound

Resume Detection

On session start, if .onex_state/active_session.yaml exists in the working directory,
suggest: "Previous session was bound to PROJ-1234. Resume? (/onex:set_session PROJ-1234)"
Do NOT auto-inject -- user must explicitly opt in.

Note: This skill executes directly (not via general-purpose) because it is a
synchronous, user-invoked operation with no need for agent routing.