Slack construct — sibling agents

This skill is a carrier for standing context, not an on-demand workflow. Its payload is instructions.md in this directory: the rules an agent needs when it shares Slack with sibling agents it can create (create_agent) and room with (create_room / add_to_room) — team-room shape, who posts the introduction, and the bot-to-bot self-limit.

The host composes every container skill's instructions.md into each group's CLAUDE.md at spawn (src/project-doc-compose.ts), so if you are reading this from inside a session, those rules are already part of your standing instructions. There is nothing further to load or run here.

The room-and-canvas half of the Slack standing context (mention engagement, canvas discipline, access rules) ships separately with the Slack channel payload as the slack-construct skill; this fragment layers the sibling-agent rules on top and arrives with the slack-agent-flow skill.