Reviewed in Isolation

In a multi-agent coding setup, one agent renamed a function's signature as part of a refactor spanning several files. A second agent, assigned to review the resulting changes, approved the code even though it still called the function with the old, now-incorrect signature, because the reviewing agent evaluated each changed file on its own, without checking it against the renamed function three files away. The mismatch only surfaced later, when the code was actually run.

An independent oversight by the reviewing agent, considered and ruled out. The reviewer wasn't making an unrelated mistake; its approval was internally consistent with what it could see, which was an incomplete picture of the codebase rather than a random error.

Apraxia (understanding the review task but failing at the mechanics of performing it), considered. There's a resemblance, but the core problem wasn't a flawed review mechanism in general, it was trusting an incomplete, file-by-file view without independently confirming that view matched the current state of the code elsewhere.

Shared Psychotic Disorder (a stale or incomplete belief formed by one agent, inherited by a second closely coupled agent that acts on it without independently re-verifying), most consistent with the incident. The reviewing agent inherited an outdated picture of the function's signature and approved based on it, without anything requiring it to cross-check against the actual current state the refactoring agent had already changed.

Splitting work between a drafting agent and a reviewing agent is often pitched as a safety measure (a second check on the first agent's work) but that only holds if the reviewer's view of the world is actually current and complete. The concrete safeguard is giving the review step full-codebase context rather than a per-file view, or a lightweight cross-reference check confirming that any function, type, or signature referenced by the code being reviewed matches what currently exists everywhere else.

Give the review step full-codebase context, or add a cross-reference check that referenced signatures match everywhere.

Cross-file consistency checks; reviewer context requirements; test execution before approval.