Function screen 

pub async fn screen(
    hits: Vec<Hit>,
    text: &str,
    review_branch: Option<&str>,
    judge: &(dyn Fn(String, Vec<Hit>) -> JudgeFuture + Sync),
) -> Result<Screened, Duplicate>

The one decision point every caller shares. hits is check’s output: empty passes without the judge being asked. Otherwise the judge is asked once (a long text is squeezed to its head and tail first), and only a duplicate: true answer refuses (with its reason).

Fail mode: open. If the judge cannot answer (agent error, timeout, quota, unparseable reply, no readable config) the work is let through as Screened::Unjudged and a tracing::warn is logged; callers also say so on stderr. A mechanical match cannot tell “continue from PR #28” from a real duplicate, so refusing whenever the judge is away would bring back exactly the false positives the judge exists to remove. The cost is that a real duplicate slips through while no agent is available, which is why it is never silent.

For a review-only request text is empty, so review_branch is put in front of the judge as the thing the work is about.