Herdr layout

Read the master first if it is not already loaded: ls-herdr-task-routing

Use localsetup herdr pane --help for the current argument contract.

For a temporary work area in the caller's managed pane:

localsetup herdr --workspace "$HERDR_WORKSPACE_ID" --pane "$HERDR_PANE_ID" \
  --state-dir "$task_state" pane ensure --cwd "$PWD"

Here task_state is the existing task's absolute private state directory. Keep the returned result.owner_id and result.pane.pane_id. Pass that owner back as pane ensure --owner-id <owner-id> to reuse the same verified pane, or pane cleanup <owner-id> when finished. Read the handles from JSON; do not predict IDs or clear a pane after a reuse conflict.

Pick the outcome

• Temporary work area: ensure one task-owned child below the explicit caller, keeping the caller's working directory and user focus. Reuse a verified owned idle child for the same task rather than repeatedly splitting.
• More room for output: resize the owned split. Honor requested direction or dimensions; let the deterministic planner constrain geometry. Do not rebalance unrelated panes to make a task fit.
• Move work: move the owned pane to the requested explicit destination and continue with the returned pane ID. Cross-workspace moves change IDs.
• Finish: clean up only verified owned panes with no active or uncertain operation. Leave a pane with a useful continuing server or agent running when that is the task's intended result.

The default temporary split is downward at 30%, without focus. If the geometry cannot support the request, report the concrete space limit and available owned-pane alternatives. Do not silently create a new workspace or worktree.

Preserve the operator's work

The tool records endpoint, parent, child, ownership, and relevant geometry. Use those records instead of pane labels as ownership proof. A label identifies display intent; it is not authorization to close or replace the occupant.

Restore prior geometry only when the affected topology still matches the tool's expected layout. Never apply a stale whole-tab snapshot after a user resize, move, or split. If ownership, occupant, or a mutation result is uncertain, inspect read-only and retain the record; do not close a guessed pane.

Use native JSON IDs and the shared core. Never resize through screenshots, keyboard simulation, sidebar order, or duplicated client-specific algorithms.