Function reading 

pub fn reading(
    card: &Card,
    answers: Option<&BTreeMap<String, Assessment>>,
) -> Assessment

How a message to a shielded address reads: the AI’s answer about this very message when it read it (found under ai_key, where sioul_sync::shield_ai keeps it), else the word lists’. Every reader goes through here (the Porch, sioul shield, the MCP server), so that none looks an answer up another way, misses it, and passes on mail the AI found hostile.