Enhance protocol and simulation features with activity tracking and behavior definitions

- Updated protocol documentation to include new `activity` and `activityLabel` fields in the person card response, reflecting real-time activity status.
- Introduced `BehaviorDef` to define behavior rules, including need thresholds and lesson skill gains, enhancing AI decision-making.
- Revised the `DefCatalog` to incorporate behavior definitions and updated validation logic to ensure proper behavior handling.
- Enhanced the simulation to manage presence and activity states, allowing for more dynamic interactions within the school environment.
- Updated tests to validate the new activity tracking and behavior functionalities, ensuring robust performance and reliability.
- Improved localization strings to support new activity and behavior features, enhancing user experience.

docs/phases/20-needs-actions.md

@@ -11,27 +11,27 @@
 
 ## Задачи
 
-- [ ] `ActionDef` получает поля: комната, вещь, длительность, восполняемая нужда и величина,
+- [x] `ActionDef` получает поля: комната, вещь, длительность, восполняемая нужда и величина,
       роли, вес досуга
-- [ ] Действия в `core`: поесть в столовой, санузел, отдохнуть на перемене, пообщаться,
+- [x] Действия в `core`: поесть в столовой, санузел, отдохнуть на перемене, пообщаться,
       прогуляться по коридору и по двору
-- [ ] Деф правил поведения — как `StaffingDef` у штата: пороги нужд, скорость обучения на уроке,
+- [x] Деф правил поведения — как `StaffingDef` у штата: пороги нужд, скорость обучения на уроке,
       разброс запаса на дорогу, порог переключения решения
-- [ ] Декей нужд включается в `core`. Сон восстанавливается вне школы, а не действием
-- [ ] Действие занимает вещь на время: за один стол не садятся вдвоём
-- [ ] Выполнение действия: начало, отсчёт минут, восполнение нужды по завершении. Правила — в
+- [x] Декей нужд включается в `core`. Сон восстанавливается вне школы, а не действием
+- [x] Действие занимает вещь на время: за один стол не садятся вдвоём
+- [x] Выполнение действия: начало, отсчёт минут, восполнение нужды по завершении. Правила — в
       `HSchool.Ai`, компоненты и мир — в `HSchool.Simulation`
-- [ ] Валидатор дефов ловит действие без комнаты, с неизвестной нуждой и с неизвестной вещью
-- [ ] Карточка человека показывает, что он делает; полоски нужд начинают шевелиться
+- [x] Валидатор дефов ловит действие без комнаты, с неизвестной нуждой и с неизвестной вещью
+- [x] Карточка человека показывает, что он делает; полоски нужд начинают шевелиться
 
 ## Тесты, без которых фаза не закрыта
 
-- [ ] Голод падает за игровой час ровно на `decayPerHour`
-- [ ] Обед в столовой поднимает голод на заявленную величину и занимает заявленное время
-- [ ] Столов меньше, чем желающих: лишние не начинают действие, а не садятся сквозь друг друга
-- [ ] Ночь вне школы возвращает сон к максимуму
-- [ ] Действие с неизвестной нуждой роняет загрузку каталога с внятной ошибкой
-- [ ] Те же входы дают те же значения нужд на тот же момент
+- [x] Голод падает за игровой час ровно на `decayPerHour`
+- [x] Обед в столовой поднимает голод на заявленную величину и занимает заявленное время
+- [x] Столов меньше, чем желающих: лишние не начинают действие, а не садятся сквозь друг друга
+- [x] Ночь вне школы возвращает сон к максимуму
+- [x] Действие с неизвестной нуждой роняет загрузку каталога с внятной ошибкой
+- [x] Те же входы дают те же значения нужд на тот же момент
 
 ## Критерий готовности
 

docs/phases/README.md

@@ -89,5 +89,5 @@
 
 | Фаза | Статус | Зачем |
 | --- | --- | --- |
-| [20. Нужды и действия](20-needs-actions.md) | ⬜ | `ActionDef` с полями, декей, восполнение |
+| [20. Нужды и действия](20-needs-actions.md) | ✅ | `ActionDef` с полями, декей, восполнение |
 | [21. Выбор действия](21-decisions.md) | ⬜ | Цели и веса, «дойти → сделать», уход с урока, рост навыка |

docs/protocol.md

@@ -218,6 +218,9 @@ and partners for a parent. The client opens another card by id; this response do
 cards. `classId` is the homeroom class for a pupil and `null` otherwise — the personal timetable
 grid fetches `GET .../timetable?classId=` with it.
 
+`activity` is the ActionDef name currently in progress, or `null` when idle. `activityLabel`
+is that def in the request locale. HTTP JSON is additive — no protocol version bump.
+
 ```json
 {
   "id": "f0.c0",
@@ -233,6 +236,8 @@ grid fetches `GET .../timetable?classId=` with it.
   "skills": [{ "id": "Math", "label": "Математика", "value": "62" }],
   "traits": [{ "defName": "Diligent", "label": "Усидчивый" }],
   "needs": [{ "id": "Sleep", "label": "Сон", "value": 1 }],
+  "activity": null,
+  "activityLabel": null,
   "family": {
     "parents": [{ "id": "f0.p1", "fullName": "Иванова Ольга Михайловна", "female": true }],
     "children": [],

src/HSchool.Ai/ActionStepper.cs

@@ -0,0 +1,53 @@
+using HSchool.Content;
+
+namespace HSchool.Ai;
+
+/// <summary>One in-progress action. <see cref="ActionId"/> is null when the person is idle.</summary>
+public readonly record struct ActivityProgress(string? ActionId, string? Thing, float RemainingMinutes)
+{
+    public static ActivityProgress Idle { get; } = new(null, null, 0f);
+
+    public bool IsActive => ActionId is not null;
+}
+
+/// <summary>
+/// Start, countdown and refill for one action. Occupancy is a count check — two people cannot
+/// take the last chair. Simulation copies this onto components; the library has no world.
+/// </summary>
+public static class ActionStepper
+{
+    public static ActivityProgress Begin(ActionDef def)
+    {
+        ArgumentNullException.ThrowIfNull(def);
+        var thing = string.IsNullOrWhiteSpace(def.Thing) ? null : def.Thing;
+        return new ActivityProgress(def.DefName, thing, def.Minutes);
+    }
+
+    public static ActivityProgress Advance(ActivityProgress activity, float minutes, out bool completed)
+    {
+        if (!activity.IsActive)
+        {
+            completed = false;
+            return activity;
+        }
+
+        var left = activity.RemainingMinutes - minutes;
+        if (left <= 0f)
+        {
+            completed = true;
+            return ActivityProgress.Idle;
+        }
+
+        completed = false;
+        return activity with { RemainingMinutes = left };
+    }
+
+    public static bool CanOccupy(int available, int occupied) => occupied < available;
+
+    public static float ApplyNeedGain(float current, ActionDef action, NeedDef need)
+    {
+        ArgumentNullException.ThrowIfNull(action);
+        ArgumentNullException.ThrowIfNull(need);
+        return Math.Clamp(current + action.NeedGain, need.Min, need.Max);
+    }
+}

src/HSchool.Ai/DayPlan.cs

@@ -12,8 +12,6 @@ public readonly record struct DayPlan(DateOnly Day, DateTime? AppearAt, DateTime
 
 public static class DayPlans
 {
-    private const int ExtraRollMax = 7;
-
     public static DayPlan Build(
         DefCatalog catalog,
         WalkGraph walks,
@@ -111,7 +109,15 @@ public static class DayPlans
     private static int SlackMinutes(DefCatalog catalog, Person person, int schoolSeed, DateOnly day)
     {
         var rng = new Random(Seed.Mix(schoolSeed, person.Id, day.DayNumber, Seed.CommuteSalt));
-        var extra = rng.Next(0, ExtraRollMax);
+        var min = 0;
+        var max = 6;
+        if (catalog.BehaviorRules is { } rules)
+        {
+            min = rules.CommuteSlackMin;
+            max = rules.CommuteSlackMax;
+        }
+
+        var extra = rng.Next(min, max + 1);
         foreach (var name in person.Traits)
         {
             if (catalog.Traits.TryGetValue(name, out var trait))

src/HSchool.Client/src/net/api.ts

@@ -264,6 +264,8 @@ export interface PersonCard {
   readonly skills: readonly LabeledStat[];
   readonly traits: readonly DefLabel[];
   readonly needs: readonly NeedStat[];
+  readonly activity: string | null;
+  readonly activityLabel: string | null;
   readonly family: {
     readonly parents: readonly PersonRel[];
     readonly children: readonly PersonRel[];

src/HSchool.Client/src/style.css

@@ -577,6 +577,12 @@ body {
   color: var(--text-muted);
 }
 
+.people__card-place,
+.people__card-activity {
+  margin: 4px 0 0;
+  color: var(--text-muted);
+}
+
 .people__section {
   margin-top: 10px;
 }

src/HSchool.Client/src/ui/personCard.ts

@@ -40,6 +40,9 @@ export function renderPersonCard(
   if (place !== undefined && place.length > 0) {
     parent.append(el('p', { class: 'people__card-place', text: place }));
   }
+  if (card.activityLabel !== null && card.activityLabel.length > 0) {
+    parent.append(el('p', { class: 'people__card-activity', text: card.activityLabel }));
+  }
   appendPairs(parent, t('peopleBody'), card.body);
   appendPairs(parent, t('peopleSkills'), card.skills);
   appendTags(parent, t('peopleTraits'), card.traits.map((row) => row.label));

src/HSchool.Content/CatalogLoader.cs

@@ -311,6 +311,7 @@ public sealed class CatalogLoader
         var staffing = new Dictionary<string, StaffingDef>(StringComparer.Ordinal);
         var dayFrames = new Dictionary<string, DayFrameDef>(StringComparer.Ordinal);
         var holidays = new Dictionary<string, HolidayDef>(StringComparer.Ordinal);
+        var behavior = new Dictionary<string, BehaviorDef>(StringComparer.Ordinal);
 
         foreach (var (key, json) in resolved)
         {
@@ -367,6 +368,9 @@ public sealed class CatalogLoader
                 case DefKind.Holiday:
                     holidays[key.Name] = Jsonc.Deserialize<HolidayDef>(json);
                     break;
+                case DefKind.Behavior:
+                    behavior[key.Name] = Jsonc.Deserialize<BehaviorDef>(json);
+                    break;
             }
         }
 
@@ -389,6 +393,7 @@ public sealed class CatalogLoader
             staffing,
             dayFrames,
             holidays,
+            behavior,
             ru,
             en);
     }

src/HSchool.Content/DefCatalog.cs

@@ -25,6 +25,7 @@ public sealed class DefCatalog
         IReadOnlyDictionary<string, StaffingDef> staffing,
         IReadOnlyDictionary<string, DayFrameDef> dayFrames,
         IReadOnlyDictionary<string, HolidayDef> holidays,
+        IReadOnlyDictionary<string, BehaviorDef> behavior,
         IReadOnlyDictionary<string, string> ru,
         IReadOnlyDictionary<string, string> en)
     {
@@ -46,18 +47,22 @@ public sealed class DefCatalog
         Staffing = staffing;
         DayFrames = dayFrames;
         Holidays = holidays;
+        Behavior = behavior;
         _ru = ru;
         _en = en;
         AnyNeedDecays = needs.Values.Any(need => !need.Abstract && need.DecayPerHour > 0f);
+        AnyNeedRestoredOffCampus = needs.Values.Any(need => !need.Abstract && need.RestoredOffCampus);
     }
 
     /// <summary>
-    /// Whether any need in these packs actually drains. Core ships every rate at zero until
-    /// something can refill them, and walking every person twenty times a second to subtract
-    /// nothing is the kind of work that multiplies by six schools.
+    /// Whether any need in these packs actually drains. Walking every person twenty times a
+    /// second to subtract nothing is the kind of work that multiplies by six schools.
     /// </summary>
     public bool AnyNeedDecays { get; }
 
+    /// <summary>Whether any need snaps to max off campus. Sleep does; hunger does not.</summary>
+    public bool AnyNeedRestoredOffCampus { get; }
+
     public IReadOnlyList<string> PackIds { get; }
 
     public IReadOnlyDictionary<string, ActionDef> Actions { get; }
@@ -94,12 +99,17 @@ public sealed class DefCatalog
 
     public IReadOnlyDictionary<string, HolidayDef> Holidays { get; }
 
+    public IReadOnlyDictionary<string, BehaviorDef> Behavior { get; }
+
     /// <summary>The one concrete staffing ruleset, or null when a pack has not defined it.</summary>
     public StaffingDef? StaffingRules => Staffing.Values.FirstOrDefault(def => !def.Abstract);
 
     /// <summary>The one concrete day frame, or null when a pack has not defined it.</summary>
     public DayFrameDef? DayFrame => DayFrames.Values.FirstOrDefault(def => !def.Abstract);
 
+    /// <summary>The one concrete behaviour ruleset, or null when a pack has not defined it.</summary>
+    public BehaviorDef? BehaviorRules => Behavior.Values.FirstOrDefault(def => !def.Abstract);
+
     private readonly IReadOnlyDictionary<string, string> _ru;
     private readonly IReadOnlyDictionary<string, string> _en;
 
@@ -124,6 +134,7 @@ public sealed class DefCatalog
             DefKind.Staffing => Staffing.GetValueOrDefault(defName),
             DefKind.DayFrame => DayFrames.GetValueOrDefault(defName),
             DefKind.Holiday => Holidays.GetValueOrDefault(defName),
+            DefKind.Behavior => Behavior.GetValueOrDefault(defName),
             _ => null,
         };
 
@@ -201,6 +212,7 @@ public sealed class DefCatalog
         StaffingDef => DefKind.Staffing,
         DayFrameDef => DefKind.DayFrame,
         HolidayDef => DefKind.Holiday,
+        BehaviorDef => DefKind.Behavior,
         _ => throw new ArgumentOutOfRangeException(nameof(def)),
     };
 

src/HSchool.Content/Defs.cs

@@ -19,6 +19,7 @@ public enum DefKind
     Staffing,
     DayFrame,
     Holiday,
+    Behavior,
 }
 
 /// <summary>Shared JSONC fields. Kind comes from the folder under <c>defs/</c>, not from the file.</summary>
@@ -31,7 +32,29 @@ public abstract class Def
     public bool Abstract { get; init; }
 }
 
-public sealed class ActionDef : Def;
+public sealed class ActionDef : Def
+{
+    /// <summary>RoomDef or TerritoryDef where this is done. Required on concrete actions.</summary>
+    public string? Room { get; init; }
+
+    /// <summary>Thing occupied for the duration. Null means the room itself is enough.</summary>
+    public string? Thing { get; init; }
+
+    /// <summary>Game minutes the action takes. Applied in full when it completes.</summary>
+    public float Minutes { get; init; }
+
+    /// <summary>NeedDef refilled on completion. Null for walks and other leisure with no refill.</summary>
+    public string? Need { get; init; }
+
+    /// <summary>Added to the need in one shot when the action finishes, then clamped to min–max.</summary>
+    public float NeedGain { get; init; }
+
+    /// <summary>Empty means every role. Values are <see cref="PersonRoles"/> ids.</summary>
+    public IReadOnlyList<string> Roles { get; init; } = [];
+
+    /// <summary>Leisure weight. Zero means phase 21 will not pick this for fun — only for a need.</summary>
+    public float Weight { get; init; }
+}
 
 public sealed class ThingDef : Def
 {

src/HSchool.Content/MapLayout.cs

@@ -15,6 +15,25 @@ public sealed class MapLayout
 
     public static MapLayout Parse(string jsonc, string? source = null) =>
         Jsonc.Deserialize<MapLayout>(Jsonc.Parse(jsonc, source));
+
+    /// <summary>RoomDef or TerritoryDef of this node, or null when the id is not on the map.</summary>
+    public string? NodeDef(string nodeId)
+    {
+        if (Territory is { } territory && territory.Id.Equals(nodeId, StringComparison.Ordinal))
+        {
+            return territory.Def;
+        }
+
+        foreach (var room in Rooms)
+        {
+            if (room.Id.Equals(nodeId, StringComparison.Ordinal))
+            {
+                return room.Def;
+            }
+        }
+
+        return null;
+    }
 }
 
 public sealed class TerritoryNode

src/HSchool.Content/PackPaths.cs

@@ -113,6 +113,9 @@ internal static class PackPaths
             case "holidays":
                 kind = DefKind.Holiday;
                 return true;
+            case "behavior":
+                kind = DefKind.Behavior;
+                return true;
             default:
                 kind = default;
                 return false;

src/HSchool.Content/PeopleDefValidator.cs

@@ -49,6 +49,16 @@ internal static class PeopleDefValidator
             ValidateHoliday(holiday);
         }
 
+        foreach (var action in catalog.Actions.Values)
+        {
+            ValidateAction(action, catalog);
+        }
+
+        foreach (var behavior in catalog.Behavior.Values)
+        {
+            ValidateBehavior(behavior);
+        }
+
         if (catalog.Staffing.Values.Count(def => !def.Abstract) > 1)
         {
             throw new ContentLoadException("A catalog may only have one concrete StaffingDef.");
@@ -59,6 +69,11 @@ internal static class PeopleDefValidator
             throw new ContentLoadException("A catalog may only have one concrete DayFrameDef.");
         }
 
+        if (catalog.Behavior.Values.Count(def => !def.Abstract) > 1)
+        {
+            throw new ContentLoadException("A catalog may only have one concrete BehaviorDef.");
+        }
+
         RequireBuildInputs(catalog);
     }
 
@@ -373,6 +388,93 @@ internal static class PeopleDefValidator
         }
     }
 
+    private static void ValidateAction(ActionDef action, DefCatalog catalog)
+    {
+        if (action.Abstract)
+        {
+            return;
+        }
+
+        if (string.IsNullOrWhiteSpace(action.Room))
+        {
+            throw new ContentLoadException($"ActionDef '{action.DefName}' needs a room.");
+        }
+
+        var roomKnown = catalog.Rooms.TryGetValue(action.Room, out var room) && !room.Abstract;
+        var territoryKnown = catalog.Territories.TryGetValue(action.Room, out var territory) && !territory.Abstract;
+        if (!roomKnown && !territoryKnown)
+        {
+            throw new ContentLoadException($"ActionDef '{action.DefName}' references unknown room '{action.Room}'.");
+        }
+
+        if (action.Minutes <= 0)
+        {
+            throw new ContentLoadException($"ActionDef '{action.DefName}' minutes must be positive.");
+        }
+
+        if (action.Weight < 0)
+        {
+            throw new ContentLoadException($"ActionDef '{action.DefName}' weight cannot be negative.");
+        }
+
+        if (!string.IsNullOrWhiteSpace(action.Thing))
+        {
+            if (!catalog.Things.TryGetValue(action.Thing, out var thing) || thing.Abstract)
+            {
+                throw new ContentLoadException($"ActionDef '{action.DefName}' references unknown ThingDef '{action.Thing}'.");
+            }
+        }
+
+        if (string.IsNullOrWhiteSpace(action.Need))
+        {
+            if (action.NeedGain != 0)
+            {
+                throw new ContentLoadException($"ActionDef '{action.DefName}' has needGain without a need.");
+            }
+        }
+        else if (!catalog.Needs.TryGetValue(action.Need, out var need) || need.Abstract)
+        {
+            throw new ContentLoadException($"ActionDef '{action.DefName}' references unknown NeedDef '{action.Need}'.");
+        }
+
+        foreach (var role in action.Roles)
+        {
+            if (!PersonRoles.IsKnown(role))
+            {
+                throw new ContentLoadException($"ActionDef '{action.DefName}' has unknown role '{role}'.");
+            }
+        }
+    }
+
+    private static void ValidateBehavior(BehaviorDef behavior)
+    {
+        if (behavior.Abstract)
+        {
+            return;
+        }
+
+        if (behavior.NeedThreshold < 0f || behavior.NeedThreshold > 1f)
+        {
+            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' needThreshold must be 0–1.");
+        }
+
+        if (behavior.LessonSkillPerHour < 0f)
+        {
+            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' lessonSkillPerHour cannot be negative.");
+        }
+
+        if (behavior.SwitchMargin < 0f)
+        {
+            throw new ContentLoadException($"BehaviorDef '{behavior.DefName}' switchMargin cannot be negative.");
+        }
+
+        if (behavior.CommuteSlackMin < 0 || behavior.CommuteSlackMax < behavior.CommuteSlackMin)
+        {
+            throw new ContentLoadException(
+                $"BehaviorDef '{behavior.DefName}' commute slack must be a non-negative range with min ≤ max.");
+        }
+    }
+
     private static void ValidateHoliday(HolidayDef holiday)
     {
         if (holiday.Abstract)

src/HSchool.Content/PeopleDefs.cs

@@ -201,6 +201,28 @@ public sealed class StaffingDef : Def
     public float WeeksPerMonth { get; init; }
 }
 
+/// <summary>
+/// One school's behaviour numbers: when a need is urgent, how fast lessons teach, commute slack,
+/// and how much a new goal must beat the current one before a person switches. A catalog may have
+/// only one concrete ruleset.
+/// </summary>
+public sealed class BehaviorDef : Def
+{
+    /// <summary>A need at or below this value is urgent. Phase 21 turns that into a goal weight.</summary>
+    public float NeedThreshold { get; init; }
+
+    /// <summary>Skill points a lesson adds per game hour, before traits and need state. Unused until phase 21.</summary>
+    public float LessonSkillPerHour { get; init; }
+
+    /// <summary>Inclusive range of extra commute minutes rolled per person per day.</summary>
+    public int CommuteSlackMin { get; init; }
+
+    public int CommuteSlackMax { get; init; }
+
+    /// <summary>A new goal must beat the current one by this much before the person switches.</summary>
+    public float SwitchMargin { get; init; }
+}
+
 public enum BodyAttributeKind
 {
     Number,
@@ -252,6 +274,12 @@ public sealed class NeedDef : Def
     public float Min { get; init; }
 
     public float Max { get; init; } = 1;
+
+    /// <summary>
+    /// When true, this need snaps to <see cref="Max"/> off campus instead of draining. Sleep
+    /// restores overnight; hunger does not keep falling at home.
+    /// </summary>
+    public bool RestoredOffCampus { get; init; }
 }
 
 public sealed class CaseTable

src/HSchool.Content/RoomOccupancy.cs

@@ -35,4 +35,43 @@ public static class RoomOccupancy
 
         return (int)Math.Clamp(pupilSlots, 0, ushort.MaxValue);
     }
+
+    /// <summary>
+    /// How many of <paramref name="thing"/> this node holds. Homeroom seats count as that many
+    /// of <see cref="RoomDef.SeatThing"/>; other rooms sum matching slot fills.
+    /// </summary>
+    public static int ThingCount(DefCatalog catalog, MapLayout map, string nodeId, string thing)
+    {
+        ArgumentNullException.ThrowIfNull(catalog);
+        ArgumentNullException.ThrowIfNull(map);
+
+        foreach (var room in map.Rooms)
+        {
+            if (!room.Id.Equals(nodeId, StringComparison.Ordinal))
+            {
+                continue;
+            }
+
+            var count = 0;
+            if (catalog.Rooms.TryGetValue(room.Def, out var def)
+                && def.Homeroom
+                && !string.IsNullOrWhiteSpace(def.SeatThing)
+                && def.SeatThing.Equals(thing, StringComparison.Ordinal))
+            {
+                count += room.Seats > 0 ? Quantity(room.Seats) : Quantity(def.DefaultSeats);
+            }
+
+            foreach (var fill in room.Slots)
+            {
+                if (fill.Thing.Equals(thing, StringComparison.Ordinal))
+                {
+                    count += Quantity(fill.Count);
+                }
+            }
+
+            return count;
+        }
+
+        return 0;
+    }
 }

src/HSchool.Server/Api/PeopleModels.cs

@@ -59,6 +59,8 @@ internal sealed record PersonCardResponse(
     IReadOnlyList<LabeledStatResponse> Skills,
     IReadOnlyList<DefLabelResponse> Traits,
     IReadOnlyList<NeedStatResponse> Needs,
+    string? Activity,
+    string? ActivityLabel,
     PersonFamilyResponse Family);
 
 internal sealed record LabeledStatResponse(string Id, string Label, string Value);

src/HSchool.Server/Game/PersonCardReader.cs

@@ -14,6 +14,9 @@ internal static class PersonCardReader
     private static readonly QueryDescription IdentityAndNeeds =
         new QueryDescription().WithAll<PersonIdentity, PersonNeeds>();
 
+    private static readonly QueryDescription IdentityAndActivity =
+        new QueryDescription().WithAll<PersonIdentity, PersonActivity>();
+
     public static PersonCardResponse? Read(School school, string personId, string locale)
     {
         var roster = school.Roster;
@@ -42,6 +45,17 @@ internal static class PersonCardReader
         }
 
         var needs = LiveNeeds(school.World, personId) ?? person.Needs;
+        var activityId = LiveActivity(school.World, personId);
+        string? activityLabel = null;
+        if (activityId is not null && catalog is not null && catalog.Actions.TryGetValue(activityId, out var action))
+        {
+            activityLabel = catalog.Label(locale, action);
+        }
+        else if (activityId is not null)
+        {
+            activityLabel = activityId;
+        }
+
         return new PersonCardResponse(
             person.Id,
             person.Name.Full,
@@ -61,6 +75,8 @@ internal static class PersonCardReader
             Skills(person, catalog, locale),
             Traits(person, catalog, locale),
             Needs(needs, catalog, locale),
+            activityId,
+            activityLabel,
             Family(roster, person));
     }
 
@@ -77,6 +93,20 @@ internal static class PersonCardReader
         return found;
     }
 
+    private static string? LiveActivity(World world, string personId)
+    {
+        string? found = null;
+        var query = IdentityAndActivity;
+        world.Query(in query, (ref PersonIdentity identity, ref PersonActivity activity) =>
+        {
+            if (identity.Id.Equals(personId, StringComparison.Ordinal) && activity.IsActive)
+            {
+                found = activity.ActionId;
+            }
+        });
+        return found;
+    }
+
     private static IReadOnlyList<LabeledStatResponse> Body(Person person, DefCatalog? catalog, string locale)
     {
         var rows = new List<LabeledStatResponse>();

src/HSchool.Server/mods/core/defs/actions/living.jsonc

@@ -0,0 +1,51 @@
+[
+  {
+    "defName": "EatLunch",
+    "room": "Cafeteria",
+    "thing": "Chair",
+    "minutes": 15,
+    "need": "Hunger",
+    "needGain": 0.5,
+    "roles": ["student", "staff"],
+    "weight": 0,
+  },
+  {
+    "defName": "UseToilet",
+    "room": "Restroom",
+    "minutes": 4,
+    "need": "Toilet",
+    "needGain": 1,
+    "roles": ["student", "staff"],
+    "weight": 0,
+  },
+  {
+    "defName": "RecessRest",
+    "room": "Corridor",
+    "minutes": 10,
+    "roles": ["student", "staff"],
+    "weight": 2,
+  },
+  {
+    "defName": "Chat",
+    "room": "Corridor",
+    "minutes": 8,
+    "need": "Social",
+    "needGain": 0.4,
+    "roles": ["student", "staff"],
+    "weight": 3,
+  },
+  {
+    "defName": "WalkCorridor",
+    "room": "Corridor",
+    "minutes": 3,
+    "roles": ["student", "staff"],
+    "weight": 1,
+  },
+  {
+    "defName": "WalkYard",
+    "room": "SchoolYard",
+    "minutes": 5,
+    "roles": ["student", "staff"],
+    "weight": 1,
+  },
+]

src/HSchool.Server/mods/core/defs/actions/sit.jsonc

@@ -1 +1 @@
-{ "defName": "Sit" }
+{ "defName": "Sit", "abstract": true }

src/HSchool.Server/mods/core/defs/behavior/rules.jsonc

@@ -0,0 +1,12 @@
+{
+  "defName": "Behavior",
+  // A need at or below this is urgent. Phase 21 turns that into a goal weight.
+  "needThreshold": 0.35,
+  // Skill points a lesson adds per game hour, before traits and need state.
+  "lessonSkillPerHour": 0.05,
+  // Inclusive extra commute minutes. 0–6 matches the previous hardcoded roll so
+  // the same seed still arrives at the same minute.
+  "commuteSlackMin": 0,
+  "commuteSlackMax": 6,
+  "switchMargin": 0.15,
+}

src/HSchool.Server/mods/core/defs/needs/needs.jsonc

@@ -1,6 +1,6 @@
 [
-  { "defName": "Sleep", "initial": 1, "decayPerHour": 0, "min": 0, "max": 1 },
-  { "defName": "Hunger", "initial": 1, "decayPerHour": 0, "min": 0, "max": 1 },
-  { "defName": "Toilet", "initial": 1, "decayPerHour": 0, "min": 0, "max": 1 },
-  { "defName": "Social", "initial": 1, "decayPerHour": 0, "min": 0, "max": 1 },
+  { "defName": "Sleep", "initial": 1, "decayPerHour": 0.05, "min": 0, "max": 1, "restoredOffCampus": true },
+  { "defName": "Hunger", "initial": 1, "decayPerHour": 0.1, "min": 0, "max": 1 },
+  { "defName": "Toilet", "initial": 1, "decayPerHour": 0.15, "min": 0, "max": 1 },
+  { "defName": "Social", "initial": 1, "decayPerHour": 0.08, "min": 0, "max": 1 },
 ]

src/HSchool.Server/mods/core/localizations/en.jsonc

@@ -1,5 +1,12 @@
 {
   "Sit": "Sit",
+  "EatLunch": "Lunch",
+  "UseToilet": "Restroom",
+  "RecessRest": "Recess",
+  "Chat": "Chat",
+  "WalkCorridor": "Walk the corridor",
+  "WalkYard": "Walk the yard",
+  "Behavior": "Behavior rules",
   "Chair": "Chair",
   "DirectorsChair": "Principal's chair",
   "Desk": "Desk",

src/HSchool.Server/mods/core/localizations/ru.jsonc

@@ -1,5 +1,12 @@
 {
   "Sit": "Сесть",
+  "EatLunch": "Обед",
+  "UseToilet": "Туалет",
+  "RecessRest": "Перемена",
+  "Chat": "Разговор",
+  "WalkCorridor": "Прогулка по коридору",
+  "WalkYard": "Прогулка во дворе",
+  "Behavior": "Правила поведения",
   "Chair": "Стул",
   "DirectorsChair": "Кресло директора",
   "Desk": "Стол",

src/HSchool.Simulation/ActivitySystem.cs

@@ -0,0 +1,160 @@
+using Arch.Core;
+using HSchool.Ai;
+using HSchool.Content;
+
+namespace HSchool.Simulation;
+
+/// <summary>
+/// Starts and ticks actions on World entities. Rules live in <see cref="ActionStepper"/>; this
+/// adapter copies them onto components and counts occupied things at a node.
+/// </summary>
+internal static class ActivitySystem
+{
+    private static readonly QueryDescription People =
+        new QueryDescription().WithAll<PersonIdentity, PersonRoles, PersonNeeds, Presence, PersonActivity>();
+
+    public static bool TryStart(School school, string personId, string actionId)
+    {
+        if (school.Catalog is null || school.Map is null)
+        {
+            return false;
+        }
+
+        if (!school.Catalog.Actions.TryGetValue(actionId, out var action) || action.Abstract)
+        {
+            return false;
+        }
+
+        var started = false;
+        var world = school.World;
+        world.Query(
+            in People,
+            (ref PersonIdentity identity, ref PersonRoles roles, ref Presence presence, ref PersonActivity activity) =>
+            {
+                if (started || !identity.Id.Equals(personId, StringComparison.Ordinal))
+                {
+                    return;
+                }
+
+                if (activity.IsActive || presence.NodeId is null)
+                {
+                    return;
+                }
+
+                if (!RoleFits(action, roles))
+                {
+                    return;
+                }
+
+                var location = school.Map.NodeDef(presence.NodeId);
+                if (location is null || !location.Equals(action.Room, StringComparison.Ordinal))
+                {
+                    return;
+                }
+
+                if (!string.IsNullOrWhiteSpace(action.Thing))
+                {
+                    var available = RoomOccupancy.ThingCount(school.Catalog, school.Map, presence.NodeId, action.Thing);
+                    var occupied = Occupied(school, presence.NodeId, action.Thing);
+                    if (!ActionStepper.CanOccupy(available, occupied))
+                    {
+                        return;
+                    }
+                }
+
+                var next = ActionStepper.Begin(action);
+                activity = new PersonActivity(next.ActionId, next.Thing, next.RemainingMinutes);
+                started = true;
+            });
+        return started;
+    }
+
+    public static void Apply(School school, double gameMinutes)
+    {
+        if (school.Catalog is null || gameMinutes <= 0)
+        {
+            return;
+        }
+
+        var catalog = school.Catalog;
+        var minutes = (float)gameMinutes;
+        var world = school.World;
+        world.Query(in People, (ref PersonNeeds needs, ref Presence presence, ref PersonActivity activity) =>
+        {
+            if (!activity.IsActive)
+            {
+                return;
+            }
+
+            if (!presence.IsOnCampus || activity.ActionId is null || !catalog.Actions.TryGetValue(activity.ActionId, out var action))
+            {
+                activity = PersonActivity.Idle;
+                return;
+            }
+
+            var next = ActionStepper.Advance(
+                new ActivityProgress(activity.ActionId, activity.Thing, activity.RemainingMinutes),
+                minutes,
+                out var completed);
+            if (!completed)
+            {
+                activity = new PersonActivity(next.ActionId, next.Thing, next.RemainingMinutes);
+                return;
+            }
+
+            if (!string.IsNullOrWhiteSpace(action.Need)
+                && catalog.Needs.TryGetValue(action.Need, out var need)
+                && needs.Values.TryGetValue(action.Need, out var current))
+            {
+                needs.Values[action.Need] = ActionStepper.ApplyNeedGain(current, action, need);
+            }
+
+            activity = PersonActivity.Idle;
+        });
+    }
+
+    private static int Occupied(School school, string nodeId, string thing)
+    {
+        var occupied = 0;
+        var world = school.World;
+        world.Query(in People, (ref Presence presence, ref PersonActivity activity) =>
+        {
+            if (activity.IsActive
+                && presence.NodeId is not null
+                && presence.NodeId.Equals(nodeId, StringComparison.Ordinal)
+                && thing.Equals(activity.Thing, StringComparison.Ordinal))
+            {
+                occupied++;
+            }
+        });
+        return occupied;
+    }
+
+    private static bool RoleFits(ActionDef action, PersonRoles roles)
+    {
+        if (action.Roles.Count == 0)
+        {
+            return true;
+        }
+
+        foreach (var role in action.Roles)
+        {
+            if (role.Equals(HSchool.Content.PersonRoles.Student, StringComparison.OrdinalIgnoreCase) && roles.IsStudent)
+            {
+                return true;
+            }
+
+            if (role.Equals(HSchool.Content.PersonRoles.Staff, StringComparison.OrdinalIgnoreCase) && roles.IsStaff)
+            {
+                return true;
+            }
+
+            if (role.Equals(HSchool.Content.PersonRoles.Parent, StringComparison.OrdinalIgnoreCase) && roles.IsParent)
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}

src/HSchool.Simulation/Components/PersonComponents.cs

@@ -22,6 +22,17 @@ public readonly record struct PersonTraits(IReadOnlyList<string> Ids);
 /// <summary>Live need values. The dictionary is mutated in place as the clock advances.</summary>
 public readonly record struct PersonNeeds(Dictionary<string, float> Values);
 
+/// <summary>
+/// The action this person is carrying out. Occupies <see cref="Thing"/> until it finishes.
+/// Idle when <see cref="ActionId"/> is null.
+/// </summary>
+public readonly record struct PersonActivity(string? ActionId, string? Thing, float RemainingMinutes)
+{
+    public static PersonActivity Idle { get; } = new(null, null, 0f);
+
+    public bool IsActive => ActionId is not null;
+}
+
 public readonly record struct PersonRoles(
     bool IsStudent,
     bool IsStaff,

src/HSchool.Simulation/NeedDecay.cs

@@ -1,26 +1,49 @@
 using Arch.Core;
+using HSchool.Ai;
 using HSchool.Content;
 
 namespace HSchool.Simulation;
 
 /// <summary>
-/// Drains needs by <see cref="NeedDef.DecayPerHour"/> × simulated hours. Core ships decay at zero
-/// so this is a no-op until something exists that can refill them.
+/// Drains needs by <see cref="NeedDef.DecayPerHour"/> × simulated hours while the person is on
+/// campus. Off campus, needs do not drain and <see cref="NeedDef.RestoredOffCampus"/> snaps to max
+/// — sleep comes back overnight, hunger does not keep falling at home.
 /// </summary>
 public static class NeedDecay
 {
-    private static readonly QueryDescription PeopleWithNeeds = new QueryDescription().WithAll<PersonNeeds>();
+    private static readonly QueryDescription PeopleWithNeeds =
+        new QueryDescription().WithAll<PersonNeeds, Presence>();
 
     public static void Apply(World world, DefCatalog catalog, double gameMinutes)
     {
-        if (gameMinutes <= 0 || !catalog.AnyNeedDecays)
+        if (gameMinutes <= 0 || (!catalog.AnyNeedDecays && !catalog.AnyNeedRestoredOffCampus))
         {
             return;
         }
 
         var hours = gameMinutes / 60d;
-        world.Query(in PeopleWithNeeds, (ref PersonNeeds needs) =>
+        world.Query(in PeopleWithNeeds, (ref PersonNeeds needs, ref Presence presence) =>
         {
+            if (!presence.IsOnCampus)
+            {
+                foreach (var def in catalog.Needs.Values)
+                {
+                    if (def.Abstract || !def.RestoredOffCampus || !needs.Values.ContainsKey(def.DefName))
+                    {
+                        continue;
+                    }
+
+                    needs.Values[def.DefName] = def.Max;
+                }
+
+                return;
+            }
+
+            if (!catalog.AnyNeedDecays)
+            {
+                return;
+            }
+
             foreach (var def in catalog.Needs.Values)
             {
                 if (def.Abstract || !needs.Values.TryGetValue(def.DefName, out var current))

src/HSchool.Simulation/PresenceSystem.cs

@@ -13,7 +13,7 @@ namespace HSchool.Simulation;
 internal static class PresenceSystem
 {
     private static readonly QueryDescription People =
-        new QueryDescription().WithAll<PersonIdentity, PersonRoles, PersonTraits, Presence>();
+        new QueryDescription().WithAll<PersonIdentity, PersonRoles, PersonTraits, Presence, PersonActivity>();
 
     public static void Apply(School school, double gameMinutes)
     {
@@ -48,7 +48,7 @@ internal static class PresenceSystem
     {
         var rows = new List<PresenceSnapshot>();
         var world = school.World;
-        world.Query(in People, (ref PersonIdentity identity, ref Presence presence) =>
+        world.Query(in People, (ref PersonIdentity identity, ref Presence presence, ref PersonActivity activity) =>
         {
             rows.Add(new PresenceSnapshot(
                 identity.Id,
@@ -56,7 +56,10 @@ internal static class PresenceSystem
                 presence.RemainingMinutes,
                 presence.DestinationId,
                 presence.HeadingHome,
-                presence.Path));
+                presence.Path,
+                activity.ActionId,
+                activity.Thing,
+                activity.RemainingMinutes));
         });
         rows.Sort((left, right) => StringComparer.Ordinal.Compare(left.PersonId, right.PersonId));
         return rows;
@@ -74,17 +77,19 @@ internal static class PresenceSystem
         var byId = saved
             .Where(row => !string.IsNullOrWhiteSpace(row.PersonId))
             .ToDictionary(row => row.PersonId, StringComparer.Ordinal);
-        ForEachPerson(school, (person, _, ref presence) =>
+        ForEachPerson(school, (person, _, ref presence, ref activity) =>
         {
             if (!byId.TryGetValue(person.Id, out var row))
             {
                 presence = PlaceByDuty(school, person);
+                activity = PersonActivity.Idle;
                 return;
             }
 
             if (row.NodeId is null)
             {
                 presence = Presence.OffCampus;
+                activity = PersonActivity.Idle;
                 return;
             }
 
@@ -94,16 +99,20 @@ internal static class PresenceSystem
                 row.DestinationId,
                 row.HeadingHome,
                 row.Path?.ToArray() ?? []);
+            activity = string.IsNullOrWhiteSpace(row.ActionId)
+                ? PersonActivity.Idle
+                : new PersonActivity(row.ActionId, row.ActionThing, row.ActionRemaining);
         });
     }
 
     public static void PlaceMissingByDuty(School school)
     {
-        ForEachPerson(school, (person, _, ref presence) =>
+        ForEachPerson(school, (person, _, ref presence, ref activity) =>
         {
             if (!presence.IsOnCampus)
             {
                 presence = PlaceByDuty(school, person);
+                activity = PersonActivity.Idle;
             }
         });
     }
@@ -323,7 +332,7 @@ internal static class PresenceSystem
         }
 
         var world = school.World;
-        world.Query(in People, (ref Presence presence) =>
+        world.Query(in People, (ref Presence presence, ref PersonActivity activity) =>
         {
             if (presence.HeadingHome
                 && presence.NodeId is not null
@@ -332,6 +341,7 @@ internal static class PresenceSystem
                 && presence.NodeId.Equals(yard, StringComparison.Ordinal))
             {
                 presence = Presence.OffCampus;
+                activity = PersonActivity.Idle;
             }
         });
     }
@@ -349,17 +359,17 @@ internal static class PresenceSystem
     private static IReadOnlyList<Person> OrderedPeople(School school) =>
         school.Roster!.People.OrderBy(person => person.Id, StringComparer.Ordinal).ToArray();
 
-    private delegate void PersonAction(Person person, PersonIdentity identity, ref Presence presence);
+    private delegate void PersonAction(Person person, PersonIdentity identity, ref Presence presence, ref PersonActivity activity);
 
     private static void ForEachPerson(School school, PersonAction action)
     {
         var roster = school.Roster!.People.ToDictionary(person => person.Id, StringComparer.Ordinal);
         var world = school.World;
-        world.Query(in People, (ref PersonIdentity identity, ref Presence presence) =>
+        world.Query(in People, (ref PersonIdentity identity, ref Presence presence, ref PersonActivity activity) =>
         {
             if (roster.TryGetValue(identity.Id, out var person))
             {
-                action(person, identity, ref presence);
+                action(person, identity, ref presence, ref activity);
             }
         });
     }
@@ -371,4 +381,7 @@ public sealed record PresenceSnapshot(
     float RemainingMinutes,
     string? DestinationId,
     bool HeadingHome,
-    IReadOnlyList<string> Path);
+    IReadOnlyList<string> Path,
+    string? ActionId = null,
+    string? ActionThing = null,
+    float ActionRemaining = 0f);

src/HSchool.Simulation/RosterSpawner.cs

@@ -38,7 +38,8 @@ public static class RosterSpawner
                     person.ClassId,
                     person.Position,
                     person.WorkplaceRoomId),
-                Presence.OffCampus);
+                Presence.OffCampus,
+                PersonActivity.Idle);
         }
     }
 

src/HSchool.Simulation/School.cs

@@ -120,6 +120,14 @@ public sealed class School : IDisposable
         DecisionQueue.Clear();
     }
 
+    public bool TryStartAction(string personId, string actionId)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        ArgumentException.ThrowIfNullOrWhiteSpace(personId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(actionId);
+        return ActivitySystem.TryStart(this, personId, actionId);
+    }
+
     public void ConfigurePresence(int weekDays = 5, int maxDecisionsPerTick = 64, int maxSkipDays = 400)
     {
         ObjectDisposedException.ThrowIf(_disposed, this);
@@ -180,6 +188,7 @@ public sealed class School : IDisposable
         peopleChanged |= TryApplicantRefresh();
         PlanDay = null;
         LastDecisionSlot = null;
+        NeedDecay.Apply(World, Catalog, (next.Value - before).TotalMinutes);
         return new SkipEmptyResult(SkipEmptyError.None, next.Value, peopleChanged);
     }
 
@@ -214,7 +223,7 @@ public sealed class School : IDisposable
         }
     }
 
-    /// <summary>Runs one fixed step of the school: calendar, yearly intake, applicant refresh, then need decay.</summary>
+    /// <summary>Runs one fixed step of the school: calendar, yearly intake, applicant refresh, presence, actions, then need decay.</summary>
     /// <returns><see langword="true"/> when the roster or the applicant pool changed this step.</returns>
     public bool Tick(double deltaTime, double gameMinutesPerRealSecond)
     {
@@ -234,6 +243,7 @@ public sealed class School : IDisposable
             }
 
             PresenceSystem.Apply(this, gameMinutes);
+            ActivitySystem.Apply(this, gameMinutes);
             if (Catalog is not null)
             {
                 NeedDecay.Apply(World, Catalog, gameMinutes);

tests/HSchool.Ai.Tests/ActionStepperTests.cs

@@ -0,0 +1,73 @@
+using HSchool.Content;
+
+namespace HSchool.Ai.Tests;
+
+public class ActionStepperTests
+{
+    private static readonly ActionDef Lunch = new()
+    {
+        DefName = "EatLunch",
+        Room = "Cafeteria",
+        Thing = "Chair",
+        Minutes = 15,
+        Need = "Hunger",
+        NeedGain = 0.5f,
+    };
+
+    private static readonly NeedDef Hunger = new()
+    {
+        DefName = "Hunger",
+        Initial = 1,
+        Min = 0,
+        Max = 1,
+    };
+
+    [Fact]
+    public void Begin_TakesTheStatedMinutes()
+    {
+        var started = ActionStepper.Begin(Lunch);
+
+        Assert.Equal("EatLunch", started.ActionId);
+        Assert.Equal("Chair", started.Thing);
+        Assert.Equal(15f, started.RemainingMinutes);
+    }
+
+    [Fact]
+    public void Advance_CompletesAfterTheStatedMinutes()
+    {
+        var started = ActionStepper.Begin(Lunch);
+
+        var mid = ActionStepper.Advance(started, 14f, out var doneEarly);
+        var done = ActionStepper.Advance(mid, 1f, out var completed);
+
+        Assert.False(doneEarly);
+        Assert.Equal(1f, mid.RemainingMinutes);
+        Assert.True(completed);
+        Assert.False(done.IsActive);
+    }
+
+    [Fact]
+    public void ApplyNeedGain_RaisesHungerByTheStatedAmount()
+    {
+        Assert.Equal(0.8f, ActionStepper.ApplyNeedGain(0.3f, Lunch, Hunger));
+        Assert.Equal(1f, ActionStepper.ApplyNeedGain(0.8f, Lunch, Hunger));
+    }
+
+    [Fact]
+    public void CanOccupy_RefusesWhenEveryThingIsTaken()
+    {
+        Assert.True(ActionStepper.CanOccupy(available: 1, occupied: 0));
+        Assert.False(ActionStepper.CanOccupy(available: 1, occupied: 1));
+        Assert.False(ActionStepper.CanOccupy(available: 0, occupied: 0));
+    }
+
+    [Fact]
+    public void SameAdvances_LeaveTheSameRemainingMinutes()
+    {
+        var first = ActionStepper.Advance(ActionStepper.Begin(Lunch), 7.5f, out _);
+        var second = ActionStepper.Advance(ActionStepper.Begin(Lunch), 7.5f, out _);
+
+        Assert.Equal(first.RemainingMinutes, second.RemainingMinutes);
+        Assert.Equal(first.ActionId, second.ActionId);
+    }
+}

tests/HSchool.Content.Tests/ActionDefTests.cs

@@ -0,0 +1,87 @@
+namespace HSchool.Content.Tests;
+
+public class ActionDefTests
+{
+    private readonly CatalogLoader _loader = new();
+
+    [Fact]
+    public void ConcreteAction_WithoutRoom_FailsLoad()
+    {
+        var ex = Assert.Throws<ContentLoadException>(() => _loader.Load(
+            [CatalogLoader.CorePackId],
+            [
+                PackDocuments.Def(
+                    CatalogLoader.CorePackId,
+                    "actions",
+                    "eat",
+                    """{ "defName": "Eat", "minutes": 15, "need": "Hunger", "needGain": 0.5 }"""),
+                PackDocuments.Def(
+                    CatalogLoader.CorePackId,
+                    "needs",
+                    "hunger",
+                    """{ "defName": "Hunger", "initial": 1, "decayPerHour": 0, "min": 0, "max": 1 }"""),
+            ]));
+
+        Assert.Contains("Eat", ex.Message, StringComparison.Ordinal);
+        Assert.Contains("room", ex.Message, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void ConcreteAction_UnknownNeed_FailsLoad()
+    {
+        var ex = Assert.Throws<ContentLoadException>(() => _loader.Load(
+            [CatalogLoader.CorePackId],
+            [
+                PackDocuments.Def(
+                    CatalogLoader.CorePackId,
+                    "rooms",
+                    "cafeteria",
+                    """{ "defName": "Cafeteria", "travelMinutes": 1 }"""),
+                PackDocuments.Def(
+                    CatalogLoader.CorePackId,
+                    "actions",
+                    "eat",
+                    """
+                    { "defName": "EatLunch", "room": "Cafeteria", "minutes": 15, "need": "Snacks", "needGain": 0.5 }
+                    """),
+            ]));
+
+        Assert.Contains("EatLunch", ex.Message, StringComparison.Ordinal);
+        Assert.Contains("Snacks", ex.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void ConcreteAction_UnknownThing_FailsLoad()
+    {
+        var ex = Assert.Throws<ContentLoadException>(() => _loader.Load(
+            [CatalogLoader.CorePackId],
+            [
+                PackDocuments.Def(
+                    CatalogLoader.CorePackId,
+                    "rooms",
+                    "cafeteria",
+                    """{ "defName": "Cafeteria", "travelMinutes": 1 }"""),
+                PackDocuments.Def(
+                    CatalogLoader.CorePackId,
+                    "actions",
+                    "eat",
+                    """
+                    { "defName": "EatLunch", "room": "Cafeteria", "thing": "Stool", "minutes": 15 }
+                    """),
+            ]));
+
+        Assert.Contains("EatLunch", ex.Message, StringComparison.Ordinal);
+        Assert.Contains("Stool", ex.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void AbstractAction_DoesNotNeedARoom()
+    {
+        var catalog = _loader.Load(
+            [CatalogLoader.CorePackId],
+            [PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }""")]);
+
+        Assert.True(catalog.Actions["Sit"].Abstract);
+        Assert.Null(catalog.Actions["Sit"].Room);
+    }
+}

tests/HSchool.Content.Tests/CatalogLoaderTests.cs

@@ -16,7 +16,7 @@ public class CatalogLoaderTests
                     "sit",
                     """
                     // a verb the Sit system already knows
-                    { "defName": "Sit", }
+                    { "defName": "Sit", "abstract": true, }
                     """),
             ]);
 
@@ -32,7 +32,7 @@ public class CatalogLoaderTests
             [
                 PackDocuments.Def(CatalogLoader.CorePackId, "things", "chair", """{ "defName": "Chair", "actions": [] }"""),
                 PackDocuments.Def("addon", "things", "chair", """{ "defName": "Chair", "actions": ["Sit"] }"""),
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
             ],
             log);
 
@@ -47,7 +47,7 @@ public class CatalogLoaderTests
         var catalog = _loader.Load(
             [CatalogLoader.CorePackId, "addon"],
             [
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
                 PackDocuments.Locale(CatalogLoader.CorePackId, "ru", """{ "Sit": "Сесть" }"""),
                 PackDocuments.Locale("addon", "ru", """{ "Sit": "Присесть" }"""),
             ],
@@ -63,7 +63,7 @@ public class CatalogLoaderTests
         var catalog = _loader.Load(
             [CatalogLoader.CorePackId],
             [
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
                 PackDocuments.Locale(CatalogLoader.CorePackId, "ru", """{ "Sit": "Сесть" }"""),
             ]);
 
@@ -77,8 +77,8 @@ public class CatalogLoaderTests
         var catalog = _loader.Load(
             ["addon"],
             [
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
-                PackDocuments.Def("addon", "actions", "wave", """{ "defName": "Wave" }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
+                PackDocuments.Def("addon", "actions", "wave", """{ "defName": "Wave", "abstract": true }"""),
             ]);
 
         Assert.Equal([CatalogLoader.CorePackId, "addon"], catalog.PackIds);

tests/HSchool.Content.Tests/InheritanceTests.cs

@@ -10,8 +10,8 @@ public class InheritanceTests
         var catalog = _loader.Load(
             [CatalogLoader.CorePackId],
             [
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "inspect", """{ "defName": "Inspect" }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "inspect", """{ "defName": "Inspect", "abstract": true }"""),
                 PackDocuments.Def(
                     CatalogLoader.CorePackId,
                     "things",

tests/HSchool.Content.Tests/MapValidationTests.cs

@@ -118,7 +118,7 @@ public class MapValidationTests
 
     private static List<ContentDocument> MiniDefs(bool abstractYard = false) =>
     [
-        PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
+        PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
         PackDocuments.Def(CatalogLoader.CorePackId, "things", "chair", """{ "defName": "Chair", "actions": ["Sit"] }"""),
         PackDocuments.Def(CatalogLoader.CorePackId, "positions", "principal", """{ "defName": "Principal" }"""),
         PackDocuments.Def(

tests/HSchool.Content.Tests/PatchTests.cs

@@ -10,8 +10,8 @@ public class PatchTests
         var catalog = _loader.Load(
             [CatalogLoader.CorePackId, "addon"],
             [
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit" }"""),
-                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "inspect", """{ "defName": "Inspect" }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "sit", """{ "defName": "Sit", "abstract": true }"""),
+                PackDocuments.Def(CatalogLoader.CorePackId, "actions", "inspect", """{ "defName": "Inspect", "abstract": true }"""),
                 PackDocuments.Def(CatalogLoader.CorePackId, "things", "chair", """{ "defName": "Chair", "actions": ["Sit"] }"""),
                 PackDocuments.Patch(
                     "addon",

tests/HSchool.Content.Tests/PeopleDefTests.cs

@@ -16,7 +16,9 @@ public class PeopleDefTests
         Assert.True(catalog.BodyAttributes.ContainsKey("Height"));
         Assert.Equal(BodyAttributeKind.Number, catalog.BodyAttributes["Height"].Kind);
         Assert.Equal(BodyAttributeKind.Choice, catalog.BodyAttributes["HairColor"].Kind);
-        Assert.All(catalog.Needs.Values, need => Assert.Equal(0, need.DecayPerHour));
+        Assert.All(catalog.Needs.Values, need => Assert.True(need.DecayPerHour > 0));
+        Assert.True(catalog.Needs["Sleep"].RestoredOffCampus);
+        Assert.Equal(0.1f, catalog.Needs["Hunger"].DecayPerHour);
         Assert.Contains(catalog.Skills["Agility"].BodyLimits, limit => limit.Attribute == "Build" && limit.Value == "Obese");
         Assert.True(catalog.NameSets.ContainsKey("Slavic"));
         Assert.True(catalog.NameSets["Slavic"].MaleGiven.Count >= 20);

tests/HSchool.Content.Tests/VanillaCoreTests.cs

@@ -64,6 +64,19 @@ public class VanillaCoreTests
         Assert.Equal(3f, catalog.Territories["SchoolYard"].TravelMinutes);
         Assert.Equal(4, catalog.Traits["Diligent"].CommuteMinutes);
         Assert.Equal(-4, catalog.Traits["Lazy"].CommuteMinutes);
+        Assert.True(catalog.Actions["Sit"].Abstract);
+        Assert.Equal("Cafeteria", catalog.Actions["EatLunch"].Room);
+        Assert.Equal("Chair", catalog.Actions["EatLunch"].Thing);
+        Assert.Equal(15f, catalog.Actions["EatLunch"].Minutes);
+        Assert.Equal("Hunger", catalog.Actions["EatLunch"].Need);
+        Assert.Equal(0.5f, catalog.Actions["EatLunch"].NeedGain);
+        Assert.Equal("SchoolYard", catalog.Actions["WalkYard"].Room);
+        Assert.Equal(0.1f, catalog.Needs["Hunger"].DecayPerHour);
+        Assert.True(catalog.Needs["Sleep"].RestoredOffCampus);
+        Assert.NotNull(catalog.BehaviorRules);
+        Assert.Equal(0, catalog.BehaviorRules.CommuteSlackMin);
+        Assert.Equal(6, catalog.BehaviorRules.CommuteSlackMax);
+        Assert.Equal(0.35f, catalog.BehaviorRules.NeedThreshold);
     }
 
     /// <summary>
@@ -97,6 +110,7 @@ public class VanillaCoreTests
         keys.AddRange(Names(catalog.Staffing.Values));
         keys.AddRange(Names(catalog.DayFrames.Values));
         keys.AddRange(Names(catalog.Holidays.Values));
+        keys.AddRange(Names(catalog.Behavior.Values));
 
         // Derived in code, so no def carries them.
         keys.Add(BodyBuilds.Attribute);

tests/HSchool.Simulation.Tests/ActivityTests.cs

@@ -0,0 +1,153 @@
+using Arch.Core;
+using HSchool.Ai;
+using HSchool.Content;
+using HSchool.People;
+
+namespace HSchool.Simulation.Tests;
+
+public class ActivityTests
+{
+    private static readonly DateTime Start = new(2012, 4, 3, 12, 0, 0, DateTimeKind.Utc);
+
+    [Fact]
+    public void EatLunch_FillsHungerAfterTheStatedMinutes()
+    {
+        using var school = OpenCafeteria(chairs: 8);
+        Spawn(school, "a", hunger: 0.3f);
+
+        Assert.True(school.TryStartAction("a", "EatLunch"));
+        school.Tick(2.8d, 5d);
+        Assert.Equal("EatLunch", ActivityOf(school, "a"));
+        Assert.Equal(0.3f, HungerOf(school, "a"));
+
+        school.Tick(0.2d, 5d);
+        Assert.Null(ActivityOf(school, "a"));
+        Assert.Equal(0.8f, HungerOf(school, "a"));
+    }
+
+    [Fact]
+    public void FewerChairsThanPeople_ExtrasDoNotStart()
+    {
+        using var school = OpenCafeteria(chairs: 1);
+        Spawn(school, "a", hunger: 0.3f);
+        Spawn(school, "b", hunger: 0.3f);
+
+        Assert.True(school.TryStartAction("a", "EatLunch"));
+        Assert.False(school.TryStartAction("b", "EatLunch"));
+        Assert.Equal("EatLunch", ActivityOf(school, "a"));
+        Assert.Null(ActivityOf(school, "b"));
+    }
+
+    private static School OpenCafeteria(int chairs)
+    {
+        var catalog = new CatalogLoader().Load(
+            [CatalogLoader.CorePackId],
+            [
+                new ContentDocument("core", "defs/actions/sit.jsonc", """{ "defName": "Sit", "abstract": true }"""),
+                new ContentDocument(
+                    "core",
+                    "defs/actions/eat.jsonc",
+                    """
+                    {
+                      "defName": "EatLunch",
+                      "room": "Cafeteria",
+                      "thing": "Chair",
+                      "minutes": 15,
+                      "need": "Hunger",
+                      "needGain": 0.5,
+                      "roles": ["student"]
+                    }
+                    """),
+                new ContentDocument(
+                    "core",
+                    "defs/needs/hunger.jsonc",
+                    """{ "defName": "Hunger", "initial": 1, "decayPerHour": 0, "min": 0, "max": 1 }"""),
+                new ContentDocument("core", "defs/things/chair.jsonc", """{ "defName": "Chair", "actions": ["Sit"] }"""),
+                new ContentDocument("core", "defs/territories/yard.jsonc", """{ "defName": "Yard", "travelMinutes": 1 }"""),
+                new ContentDocument("core", "defs/buildings/main.jsonc", """{ "defName": "Main" }"""),
+                new ContentDocument("core", "defs/floors/floor.jsonc", """{ "defName": "Floor" }"""),
+                new ContentDocument(
+                    "core",
+                    "defs/rooms/cafeteria.jsonc",
+                    """
+                    {
+                      "defName": "Cafeteria",
+                      "slots": [{ "key": "seats", "thing": "Chair" }],
+                      "travelMinutes": 1
+                    }
+                    """),
+            ]);
+        var map = new MapLayout
+        {
+            Territory = new TerritoryNode { Id = "yard", Def = "Yard" },
+            Buildings = [new BuildingNode { Id = "main", Def = "Main" }],
+            Floors = [new FloorNode { Id = "floor-1", Def = "Floor", Building = "main" }],
+            Rooms =
+            [
+                new RoomNode
+                {
+                    Id = "cafe",
+                    Def = "Cafeteria",
+                    Building = "main",
+                    Floor = "floor-1",
+                    Slots = [new SlotFill { Key = "seats", Thing = "Chair", Count = chairs }],
+                },
+            ],
+            Links = [new MapLink { A = "yard", B = "cafe" }],
+        };
+        MapValidator.Validate(map, catalog);
+        return School.Create(1, "Столовая", Start, catalog, map);
+    }
+
+    private static void Spawn(School school, string id, float hunger)
+    {
+        school.World.Create(
+            new PersonIdentity(id, "f", false, Start, DummyName()),
+            new PersonRoles(true, false, false, null, null, null),
+            new PersonNeeds(new Dictionary<string, float>(StringComparer.Ordinal) { ["Hunger"] = hunger }),
+            new Presence("cafe", 0f, "cafe", false, []),
+            PersonActivity.Idle);
+    }
+
+    private static string? ActivityOf(School school, string id)
+    {
+        string? found = null;
+        var query = new QueryDescription().WithAll<PersonIdentity, PersonActivity>();
+        school.World.Query(in query, (ref PersonIdentity identity, ref PersonActivity activity) =>
+        {
+            if (identity.Id.Equals(id, StringComparison.Ordinal))
+            {
+                found = activity.ActionId;
+            }
+        });
+        return found;
+    }
+
+    private static float HungerOf(School school, string id)
+    {
+        var value = float.NaN;
+        var query = new QueryDescription().WithAll<PersonIdentity, PersonNeeds>();
+        school.World.Query(in query, (ref PersonIdentity identity, ref PersonNeeds needs) =>
+        {
+            if (identity.Id.Equals(id, StringComparison.Ordinal))
+            {
+                value = needs.Values["Hunger"];
+            }
+        });
+        return value;
+    }
+
+    private static PersonName DummyName()
+    {
+        var cases = new CaseTable
+        {
+            Nom = "А",
+            Gen = "А",
+            Dat = "А",
+            Acc = "А",
+            Ins = "А",
+            Pre = "А",
+        };
+        return new PersonName("А", "А", "А", cases, cases, cases);
+    }
+}

tests/HSchool.Simulation.Tests/NeedDecayTests.cs

@@ -0,0 +1,110 @@
+using Arch.Core;
+using HSchool.Ai;
+using HSchool.Content;
+
+namespace HSchool.Simulation.Tests;
+
+public class NeedDecayTests
+{
+    [Fact]
+    public void Hunger_DropsByDecayPerHourOnCampus()
+    {
+        var catalog = VanillaCatalog();
+        var hunger = catalog.Needs["Hunger"];
+        var world = World.Create();
+        try
+        {
+            world.Create(
+                new PersonNeeds(new Dictionary<string, float>(StringComparer.Ordinal) { ["Hunger"] = hunger.Initial }),
+                new Presence("cafeteria", 0f, "cafeteria", false, []));
+            NeedDecay.Apply(world, catalog, gameMinutes: 60);
+
+            var query = new QueryDescription().WithAll<PersonNeeds>();
+            world.Query(
+                in query,
+                (ref PersonNeeds needs) =>
+                    Assert.Equal(hunger.Initial - hunger.DecayPerHour, needs.Values["Hunger"], precision: 4));
+        }
+        finally
+        {
+            World.Destroy(world);
+        }
+    }
+
+    [Fact]
+    public void Sleep_ReturnsToMaxOffCampus()
+    {
+        var catalog = VanillaCatalog();
+        var world = World.Create();
+        try
+        {
+            world.Create(
+                new PersonNeeds(new Dictionary<string, float>(StringComparer.Ordinal)
+                {
+                    ["Sleep"] = 0.2f,
+                    ["Hunger"] = 0.4f,
+                }),
+                Presence.OffCampus);
+            NeedDecay.Apply(world, catalog, gameMinutes: 60);
+
+            var query = new QueryDescription().WithAll<PersonNeeds>();
+            world.Query(in query, (ref PersonNeeds needs) =>
+            {
+                Assert.Equal(catalog.Needs["Sleep"].Max, needs.Values["Sleep"]);
+                Assert.Equal(0.4f, needs.Values["Hunger"]);
+            });
+        }
+        finally
+        {
+            World.Destroy(world);
+        }
+    }
+
+    [Fact]
+    public void SameInputs_LeaveTheSameNeedValues()
+    {
+        var catalog = VanillaCatalog();
+        var first = HungerAfterHour(catalog);
+        var second = HungerAfterHour(catalog);
+        Assert.Equal(first, second);
+    }
+
+    private static float HungerAfterHour(DefCatalog catalog)
+    {
+        var world = World.Create();
+        try
+        {
+            world.Create(
+                new PersonNeeds(new Dictionary<string, float>(StringComparer.Ordinal) { ["Hunger"] = 1f }),
+                new Presence("cafeteria", 0f, "cafeteria", false, []));
+            NeedDecay.Apply(world, catalog, gameMinutes: 60);
+            var value = 0f;
+            var query = new QueryDescription().WithAll<PersonNeeds>();
+            world.Query(in query, (ref PersonNeeds needs) => value = needs.Values["Hunger"]);
+            return value;
+        }
+        finally
+        {
+            World.Destroy(world);
+        }
+    }
+
+    private static DefCatalog VanillaCatalog()
+    {
+        var root = Path.Combine(AppContext.BaseDirectory, "vanilla");
+        var documents = new List<ContentDocument>();
+        foreach (var path in Directory.EnumerateFiles(root, "*.*", SearchOption.AllDirectories))
+        {
+            if (!path.EndsWith(".jsonc", StringComparison.OrdinalIgnoreCase)
+                && !path.EndsWith(".json", StringComparison.OrdinalIgnoreCase))
+            {
+                continue;
+            }
+
+            var relative = Path.GetRelativePath(root, path).Replace('\\', '/');
+            documents.Add(new ContentDocument(CatalogLoader.CorePackId, relative, File.ReadAllText(path)));
+        }
+
+        return new CatalogLoader().Load([CatalogLoader.CorePackId], documents);
+    }
+}

tests/HSchool.Simulation.Tests/PeopleInSchoolTests.cs

@@ -1,4 +1,5 @@
 using Arch.Core;
+using HSchool.Ai;
 using HSchool.Content;
 using HSchool.People;
 
@@ -56,7 +57,7 @@ public class PeopleInSchoolTests
     }
 
     [Fact]
-    public void CoreNeeds_DoNotMoveOnTick()
+    public void OffCampusNeeds_DoNotMoveOnTick()
     {
         var (catalog, map) = Vanilla();
         var roster = RosterGenerator.Generate(catalog, map, schoolSeed: 2, "Slavic", Start);
@@ -90,7 +91,9 @@ public class PeopleInSchoolTests
         var world = World.Create();
         try
         {
-            world.Create(new PersonNeeds(new Dictionary<string, float>(StringComparer.Ordinal) { ["Hunger"] = 1f }));
+            world.Create(
+                new PersonNeeds(new Dictionary<string, float>(StringComparer.Ordinal) { ["Hunger"] = 1f }),
+                new Presence("yard", 0f, "yard", false, []));
             NeedDecay.Apply(world, catalog, gameMinutes: 60);
             var query = new QueryDescription().WithAll<PersonNeeds>();
             world.Query(in query, (ref PersonNeeds needs) => Assert.Equal(0f, needs.Values["Hunger"]));

tests/HSchool.Simulation.Tests/SchoolTests.cs

@@ -48,7 +48,7 @@ public class SchoolTests
         var loader = new CatalogLoader();
         var documents = new[]
         {
-            new ContentDocument("core", "defs/actions/sit.jsonc", """{ "defName": "Sit" }"""),
+            new ContentDocument("core", "defs/actions/sit.jsonc", """{ "defName": "Sit", "abstract": true }"""),
             new ContentDocument("core", "defs/things/chair.jsonc", """{ "defName": "Chair", "actions": ["Sit"] }"""),
             new ContentDocument("core", "defs/territories/yard.jsonc", """{ "defName": "Yard", "travelMinutes": 1 }"""),
             new ContentDocument("core", "defs/buildings/main.jsonc", """{ "defName": "Main" }"""),