fix: say when bike share, transit and place limits leave results out

Bike share and transit read only the three nearest systems, and place
search returns at most five matches within 50 km, while answers read as
complete. Answers now name the systems not searched and say when a place
search limit may have left places out.

src/tools/queries/mobility.js

@@ -24,18 +24,32 @@ const MAX_SYSTEMS = 3;
 const round = (value, digits) =>
   Number.isFinite(value) ? Number(value.toFixed(digits)) : null;
 
-/** Systems or feeds whose coverage reaches the area, nearest first. */
+/**
+ * Systems or feeds whose coverage reaches the area, nearest first: the
+ * nearest MAX_SYSTEMS are read and the rest are returned as `skipped`.
+ */
 function covering(area, entries, centerOf, radiusOf) {
   const center = areaCenter(area);
   const reach = areaRadiusKm(area);
-  return entries
+  const reaching = entries
     .map((entry) => ({ entry, distance: distanceKm(center, centerOf(entry)) }))
     .filter(({ entry, distance }) => distance <= reach + radiusOf(entry))
     .sort((a, b) => a.distance - b.distance)
-    .slice(0, MAX_SYSTEMS)
     .map(({ entry }) => entry);
+  return {
+    selected: reaching.slice(0, MAX_SYSTEMS),
+    skipped: reaching.slice(MAX_SYSTEMS),
+  };
 }
 
+/** A note naming systems left out of an answer, or an empty list. */
+const skippedNote = (skipped, nameOf) =>
+  skipped.length
+    ? [
+        `${skipped.length} more not searched: ${skipped.map(nameOf).join(', ')}; use a smaller area`,
+      ]
+    : [];
+
 export const getBikeShare = defineTool({
   name: 'get_bike_share',
   title: 'Bike-share stations',
@@ -52,7 +66,7 @@ export const getBikeShare = defineTool({
   async run(args, { services, signal }) {
     const area = await resolveArea(args.area, { services, signal });
     const { bikeshare } = services;
-    const systems = covering(
+    const { selected: systems, skipped } = covering(
       area,
       bikeshare.systems,
       (system) => ({ lat: system.centerLat, lon: system.centerLon }),
@@ -110,14 +124,19 @@ export const getBikeShare = defineTool({
     const failed = results.filter(
       (result) => result.status === 'rejected',
     ).length;
+    const notes = [
+      ...(failed ? [`${countNoun(failed, 'system')} unavailable`] : []),
+      ...skippedNote(skipped, (system) => system.city),
+    ];
     return {
       summary:
         `${countNoun(rows.length, 'bike-share station')} in ${area.label} with ` +
         `${countNoun(bikes, 'bike')} available` +
-        (failed ? ` (${countNoun(failed, 'system')} unavailable).` : '.'),
+        (notes.length ? ` (${notes.join('; ')}).` : '.'),
       data: {
         ...capRows(rows, args.limit),
         systems: systems.map((system) => system.city),
+        systems_not_searched: skipped.map((system) => system.city),
         bikes_available: bikes,
       },
     };
@@ -149,7 +168,7 @@ export const getTransitVehicles = defineTool({
   requires: ['transit'],
   async run(args, { services, signal }) {
     const area = await resolveArea(args.area, { services, signal });
-    const feeds = covering(
+    const { selected: feeds, skipped } = covering(
       area,
       await services.transit.getFeeds({ signal }),
       (feed) => feed.center,
@@ -248,6 +267,7 @@ export const getTransitVehicles = defineTool({
             `${countNoun(staleFeeds, 'feed')} stale; positions may be out of date`,
           ]
         : []),
+      ...skippedNote(skipped, (feed) => feed.name),
     ];
     const what = args.route ? ` on route ${args.route}` : '';
     return {
@@ -258,6 +278,7 @@ export const getTransitVehicles = defineTool({
         ...capRows(rows, args.limit),
         stale: staleFeeds > 0,
         expired_positions_dropped: expired,
+        feeds_not_searched: skipped.map((feed) => feed.name),
         feeds: feeds.map((feed, index) => ({
           name: feed.name,
           status: