Role Collapse: When Execution and Verification Share a Space

A system can have designated verification — a separate evaluation step, a second agent, an external audit — and still be structurally unable to detect its ownfailure modes. This note documents a specific mechanism behind this failure:Role Collapse. The mechanism activates when execution and verification operate in the same representational space. Under this condition, verification cannotexpand fault coverage beyond what execution already produces — regardless of whether verification is performed by a separate agent, a different team, or anexternal institution. Seven cases across AI-production, ERP, and institutional governance instantiate the mechanism. One prevention architecture shows under what structural conditions it does not activate.