diff --git a/AGENTS.md b/CLAUDE.md
similarity index 100%
rename from AGENTS.md
rename to CLAUDE.md
diff --git a/agenda/types.py b/agenda/types.py
index d1ecdda..94830fd 100644
--- a/agenda/types.py
+++ b/agenda/types.py
@@ -202,18 +202,13 @@ class Trip:
         """Countries flags for trip."""
         return "".join(c.flag for c in self.countries)
 
-    def total_distance(self) -> float:
-        """Total distance for trip.
-
-        Sums distances for travel items where a distance value is present.
-        Ignores legs with missing or falsy distances rather than returning None.
-        """
-        total = 0.0
-        for t in self.travel:
-            distance = t.get("distance")
-            if distance:
-                total += distance
-        return total
+    def total_distance(self) -> float | None:
+        """Total distance for trip."""
+        return (
+            sum(t["distance"] for t in self.travel)
+            if all(t.get("distance") for t in self.travel)
+            else None
+        )
 
     def total_co2_kg(self) -> float | None:
         """Total CO₂ for trip."""