/play alone lists the world's characters and marks the one on stage; /play <slug> writes the stage-taking event at the current clock, says so in an aside, and the next turn carries the new sheet through the engine's own fresh-per-turn binding. Naming nobody lists what exists, and naming the character already on stage writes no second event. A session that opens on several characters with none on stage says so after the banner and points at /play. The screen reaches the campaign through a Stage handle the way it reads the clock, so the loop stays testable with fakes, and /play tab-completes with the other slash commands. Step 4 of plan 0014, which completes the plan. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HvctyUUkzw7PcNrjCGG6dF