The Plot Refuses the Author: Diegetic Contestability for Character-Driven AI Co-Writing

The tension between an authored plot and autonomous character behaviour is longstanding in interactive narrative, and representative systems reconcile it by planning, steering, or rewriting toward a plan. We ask what happens when a system stops resolving that disagreement and puts it in front of the writer. We introduce diegetic contestability: a simulated fictional character may challenge a proposed narrative action by citing persistent commitments established inside the fiction, take part in revision, and preserve the disagreement when the human author overrides it. Four mechanisms operationalise it: an author-visible Character Constitution; an ACCEPT/NEGOTIATE/REFUSE stance whose objections cite constitution entries by identifier; a mediator that proposes constitution-compatible alternatives without selecting one; and an append-only Authorial Override Ledger. We describe a working prototype and a worked case in an original living-shadow story world. The vocabulary of refusal is theatrical. The system does not establish that the underlying model has beliefs, interests, consent, or subjective agency, and we report no evaluation.