summary: Ticket 00001KVTNAY20 は implementation_ready。専用 worktree `/home/hare/Projects/yoi/.worktree/00001KVTNAY20-worker-runtime-spawn` と branch `work/00001KVTNAY20-worker-runtime-spawn` で、Workspace Worker runtime spawn abstraction を実装し、routing record の IntentPacket を基準に coder/reviewer sibling loop へ進める。root/original workspace では git/read/write/validate/merge/cleanup を行わない。

role_plan: Orchestrator: acceptance/routing, worktree creation, final integration/validation/cleanup. Coder: implementation in dedicated child worktree with narrow write scope. Reviewer: read-only review by default against recorded IntentPacket, validation evidence, and diff. Orchestrator handles merge into orchestration branch after reviewer approval.

author: yoi-orchestrator


note: Coder sibling execution is temporarily blocked by runtime/provider startup failures, not by Ticket requirements. `builtin:coder` started but both initial run and retry failed with provider API error `Unsupported content type`; alternate `inherit` / `builtin:default` / `builtin:companion` recovery attempts did not produce a socket within 10s. Worktree `/home/hare/Projects/yoi/.worktree/00001KVTNAY20-worker-runtime-spawn` remains clean at orchestration commit `b8388655`; no implementation diff exists yet. Human/tooling follow-up is needed before continuing multi-agent implementation, unless Orchestrator is explicitly authorized to implement directly.