diff --git a/swarm-controller/src/subagent_term.rs b/swarm-controller/src/subagent_term.rs
index 54a9a9e7a..b662f7986 100644
--- a/swarm-controller/src/subagent_term.rs
+++ b/swarm-controller/src/subagent_term.rs
@@ -472,9 +472,102 @@ fn read_failed(agent: &str, e: &dyn std::error::Error) -> problem_details::Probl
 
 #[cfg(test)]
 mod tests {
-    use super::header;
+    use super::{NewestRow, SubagentEntry, SubagentState, entry_of, header};
+    use swarm_wire::subagent_status::{STALE_AFTER_S, State, Status};
     use swarm_wire::subagent_term::{HEADER_EFFORT, HEADER_MODEL, subagent_names};
 
+    const NOW: i64 = 1_000_000;
+
+    fn status(state: State, since: i64, ts: i64) -> Status {
+        Status {
+            state,
+            since,
+            exit: None,
+            model: Some("opus".to_owned()),
+            effort: Some("high".to_owned()),
+            ts,
+        }
+    }
+
+    fn row() -> NewestRow {
+        NewestRow {
+            unix: NOW - 30,
+            model: Some("haiku".to_owned()),
+            effort: None,
+        }
+    }
+
+    /// A running status counts as running until three heartbeats are missed,
+    /// then stale; a finished one is finished however fresh it is.
+    #[test]
+    fn a_state_is_running_until_its_heartbeats_stop() {
+        let fresh = status(State::Running, NOW - 500, NOW - 10);
+        assert_eq!(SubagentState::of(&fresh, NOW), SubagentState::Running);
+        let edge = status(State::Running, NOW - 500, NOW - STALE_AFTER_S);
+        assert_eq!(SubagentState::of(&edge, NOW), SubagentState::Running);
+        let silent = status(State::Running, NOW - 500, NOW - STALE_AFTER_S - 1);
+        assert_eq!(SubagentState::of(&silent, NOW), SubagentState::Stale);
+        let done = status(State::Finished, NOW - 500, NOW - 1);
+        assert_eq!(SubagentState::of(&done, NOW), SubagentState::Finished);
+    }
+
+    /// With a status the entry takes the state, the start, the exit status
+    /// and the model and effort from it, and ignores any newest row.
+    #[test]
+    fn a_status_decides_the_entry_over_the_newest_row() {
+        let mut done = status(State::Finished, NOW - 500, NOW - 1);
+        done.exit = Some(2);
+        let entry = entry_of("scout".to_owned(), Some(done), Some(Ok(row())), NOW);
+        assert_eq!(
+            entry,
+            SubagentEntry {
+                name: "scout".to_owned(),
+                last_row_unix: None,
+                model: Some("opus".to_owned()),
+                effort: Some("high".to_owned()),
+                state: Some(SubagentState::Finished),
+                since_unix: Some(NOW - 500),
+                exit: Some(2),
+            }
+        );
+    }
+
+    /// Without a status, as from an older daemon, the entry is what the newest
+    /// row says and has no state, so the swarm UI judges it from the row's age.
+    #[test]
+    fn without_a_status_the_entry_is_the_newest_row() {
+        let entry = entry_of("scout".to_owned(), None, Some(Ok(row())), NOW);
+        assert_eq!(
+            entry,
+            SubagentEntry {
+                name: "scout".to_owned(),
+                last_row_unix: Some(NOW - 30),
+                model: Some("haiku".to_owned()),
+                effort: None,
+                state: None,
+                since_unix: None,
+                exit: None,
+            }
+        );
+    }
+
+    /// A row that could not be read leaves the time and headers out and
+    /// still lists the subagent.
+    #[test]
+    fn a_failed_row_lookup_still_lists_the_subagent() {
+        let failed = entry_of(
+            "scout".to_owned(),
+            None,
+            Some(Err("timeout".to_owned())),
+            NOW,
+        );
+        assert_eq!(failed.name, "scout");
+        assert_eq!(failed.last_row_unix, None);
+        assert_eq!(failed.state, None);
+        let skipped = entry_of("scout".to_owned(), None, None, NOW);
+        assert_eq!(skipped, failed);
+    }
+
     /// The list is what `STREAM.INFO` reports for the stream's subjects, by
     /// name: a subagent that published once and one that published many rows
     /// list the same way, and the order is the name's, not the stream's.