The Roster Pattern

Most real engineering work breaks into four phases. The planner reads the issue, drafts a plan, asks for approval. The builder executes the plan in code. The reviewer audits the diff for missing tests, leaks, and unsafe assumptions. The deployer pushes to staging, runs smoke tests, opens the PR.

Each role is a separate agent with its own system prompt and tool access. The planner can read but cannot edit. The builder can edit but cannot deploy. The reviewer can comment but cannot merge. The deployer can deploy but cannot edit. Separation of capability is the whole point of the pattern — it prevents one agent from cutting corners.