Brett je Einheit, Stufe 3: Aufgaben sehen, wer sie sehen soll (#684)

- TaskBoard: das Brett einer Aufgabe wird nicht gespeichert, es folgt aus
  der Organisation - Einheit des Zustaendigen, sonst des Anlegers. Offene
  Aufgaben ziehen damit beim Umzug mit. Sichtbar: das eigene Brett, fuer eine
  Leitung alle darunter, und was man selbst angelegt hat (nach oben
  Gereichtes bleibt im Blick).
- TaskItem.CreatedBy, in der Datei als created_by und in der DB. Ein Import
  aus einer Datei ohne das Feld behaelt, was die DB weiss.
- Taskboard-Tool: task_list, task_find und die Dublettenpruefung sehen nur
  die eigenen Bretter - eine aehnliche Buchhaltungsaufgabe haelt keine
  Marketingaufgabe auf und bekommt keinen Kommentar von dort. task_update und
  task_comment antworten auf eine fremde Aufgabe wie auf eine unbekannte.
- TaskboardService.ListAsync mit Sichtfilter: erst filtern, dann kappen.
- WebUI: jede Aufgabe nennt ihr Brett, ein Filter waehlt eines aus.
- Konzept (Abschnitt 3) und Einrichtungshandbuch nachgetragen.

Ohne Einheiten aendert sich nichts - ein Brett fuer alle.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/InstanceSetupGuide.md

@@ -64,6 +64,8 @@ Instance-{Name}/
     ├── AgentList.json             ← Agenten-Register (Name, Beschreibung, Ordner)
     ├── SharedWorkspace/           ← Geteilter Arbeitsbereich
     │   └── coordination/          ← Status-Dateien für Inter-Agenten-Kommunikation
+    ├── SharedWorkspaces/          ← Bereiche mit Mitgliederliste (#684), einer je Einheit
+    │   └── {bereich}/             ← in FileRW als workspace "unit" oder "{bereich}"
     └── Agent-{Name}/
         ├── AgentSettings.json     ← Agent-Konfiguration (Modell, Tools, Scheduler)
         ├── Identity.md            ← WER ist der Agent (Rolle, Expertise)

docs/Organisation-Konzept.md

@@ -244,6 +244,25 @@ Vier Festlegungen:
 Für bestehende Instanzen bleibt `workspace: "shared"` gültig und zeigt auf den einen
 Bereich, den es dort gibt. Ohne das bräche jede Aufgabe, die heute läuft.
 
+**Umgesetzt am 2026-09-24 (#684), mit zwei Abweichungen im Wortlaut, nicht in der Sache:**
+
+- Der Ordner `SharedWorkspace` wird **nicht umbenannt**. Er bleibt der Bereich `shared`
+  mit dem bisherigen `sharedAccessLevel` am Agenten; die neuen Bereiche liegen daneben
+  unter `SharedWorkspaces/<id>/`. Am alten Pfad hängen FTP, RocketChat, der Agenten-Editor,
+  die Aufgabendateien und die Sicherungen — eine Umbenennung hätte jede laufende
+  Installation gebrochen. Für jeden Bereich gibt es genau eine Quelle des Rechts: für
+  `shared` die Stufe am Agenten, für alle anderen die Mitgliederliste.
+- Der eigene Bereich einer Einheit trägt ihre Id; ein Agent erreicht ihn in FileRW als
+  `unit`, ohne die Id zu kennen. Welche Bereiche er hat, steht im Organisationsabschnitt
+  seines Prompts.
+- **Mit Einheiten ist `shared:/tasks/` für FileRW gesperrt.** Eine direkt geschriebene
+  Aufgabendatei ginge an jeder Prüfung des Bretts vorbei. Aufgaben laufen nur über das
+  Taskboard. Ohne Einheiten ändert sich nichts.
+- **Das Brett einer Aufgabe wird nicht gespeichert**, es folgt aus der Organisation: die
+  Einheit des Zuständigen, sonst die des Anlegers (`created_by`). Offene Aufgaben ziehen
+  damit beim Umzug von selbst mit. Wer eine Aufgabe angelegt hat, sieht sie auch, wenn sie
+  auf dem Brett der Leitung liegt.
+
 ### Die eine Regel, die alles zusammenhält
 
 **Ein Agent kennt nur seine Einheit und seine Leitung.** Alles andere geht über die

src/ClawdDotNet.Core/Storage/SqliteStorage.cs

@@ -377,6 +377,9 @@ public sealed class SqliteStorage
         SpalteErgaenzen(connection, "Tasks", "DeferredUntil", "TEXT NULL");
         SpalteErgaenzen(connection, "Tasks", "CatchUpPending", "INTEGER NOT NULL DEFAULT 0");
 
+        // #684: Who created a task — decides its board when nobody in particular is assigned.
+        SpalteErgaenzen(connection, "Tasks", "CreatedBy", "TEXT NOT NULL DEFAULT ''");
+
         // Findet offene Aufrufe beim Start, ohne die ganze Tabelle zu lesen.
         using var index = connection.CreateCommand();
         index.CommandText = """

src/ClawdDotNet.Core/Tasks/SqliteTaskRepository.cs

@@ -34,11 +34,11 @@ public sealed class SqliteTaskRepository : ITaskRepository
                     INSERT INTO Tasks
                         (Id, Title, Status, Type, Priority, Assignee, WhenKind, WhenValue, WhenTz,
                          RequireApproval, Acceptance, BlockedBy, OnlyWhenMarketOpen, Body, FileName,
-                         ToolName, JobTypeId, LastOccurrence, ClaimToken, ClaimedAt, CreatedAt, UpdatedAt)
+                         ToolName, JobTypeId, LastOccurrence, ClaimToken, ClaimedAt, CreatedAt, UpdatedAt, CreatedBy)
                     VALUES
                         (@id, @title, @status, @type, @priority, @assignee, @whenKind, @whenValue, @whenTz,
                          @requireApproval, @acceptance, @blockedBy, @market, @body, @fileName,
-                         @toolName, @jobType, NULL, NULL, NULL, @createdAt, @updatedAt);
+                         @toolName, @jobType, NULL, NULL, NULL, @createdAt, @updatedAt, @createdBy);
                     """;
                 BindDefinition(insert, task);
                 insert.Parameters.AddWithValue("@status", TaskText.Of(task.Status));
@@ -60,6 +60,7 @@ public sealed class SqliteTaskRepository : ITaskRepository
                            RequireApproval = @requireApproval, Acceptance = @acceptance,
                            BlockedBy = @blockedBy, OnlyWhenMarketOpen = @market, Body = @body,
                            FileName = @fileName, ToolName = @toolName, JobTypeId = @jobType,
+                           CreatedBy = CASE WHEN @createdBy = '' THEN CreatedBy ELSE @createdBy END,
                            UpdatedAt = @updatedAt
                      WHERE Id = @id
                     """;
@@ -331,7 +332,7 @@ public sealed class SqliteTaskRepository : ITaskRepository
         "Id, Title, Status, Type, Priority, Assignee, WhenKind, WhenValue, WhenTz, " +
         "RequireApproval, Acceptance, BlockedBy, OnlyWhenMarketOpen, Body, FileName, " +
         "ToolName, JobTypeId, LastOccurrence, ClaimToken, ClaimedAt, CreatedAt, UpdatedAt, "
-        + "BudgetMissCount, LastBudgetMissAt, DeferredUntil, CatchUpPending";
+        + "BudgetMissCount, LastBudgetMissAt, DeferredUntil, CatchUpPending, CreatedBy";
 
     private static void BindDefinition(SqliteCommand cmd, TaskItem task)
     {
@@ -351,6 +352,8 @@ public sealed class SqliteTaskRepository : ITaskRepository
         cmd.Parameters.AddWithValue("@fileName", task.FileName);
         cmd.Parameters.AddWithValue("@toolName", task.ToolName);
         cmd.Parameters.AddWithValue("@jobType", task.JobTypeId);
+        // #684: a file without it (written by hand, or older) keeps what the database knows.
+        cmd.Parameters.AddWithValue("@createdBy", task.CreatedBy ?? "");
     }
 
     private static async Task<TaskItem?> ReadAsync(SqliteConnection conn, string id, CancellationToken ct)
@@ -401,7 +404,8 @@ public sealed class SqliteTaskRepository : ITaskRepository
             BudgetMissCount = r.GetInt32(22),
             LastBudgetMissAt = r.IsDBNull(23) ? null : Parse(r.GetString(23)),
             DeferredUntil = r.IsDBNull(24) ? null : Parse(r.GetString(24)),
-            CatchUpPending = r.GetInt32(25) != 0
+            CatchUpPending = r.GetInt32(25) != 0,
+            CreatedBy = r.GetString(26)
         };
     }
 

src/ClawdDotNet.Core/Tasks/TaskBoard.cs

@@ -0,0 +1,78 @@
+using ClawdDotNet.Core.Organisation;
+
+namespace ClawdDotNet.Core.Tasks;
+
+/// <summary>
+/// #684: One board per unit. With 50 agents one board for everything is worthless as an
+/// overview — the test instance had 159 tasks with seven agents — and a bookkeeping task
+/// could slow down the creation of a marketing task through the duplicate check.
+///
+/// <para><b>The board of a task is not stored, it follows from the organisation:</b> the unit
+/// of the agent it is assigned to, or — for a task for a human or a fresh run — the unit of
+/// the agent that created it. So open tasks move with an agent that moves (Organisation-
+/// Konzept, section 3), and nothing has to be migrated. A task that belongs to no unit is on
+/// the board of the top level.</para>
+///
+/// <para><b>Who sees which board:</b> an agent its own unit's; a lead also the boards of every
+/// unit below the one it leads; everyone the tasks they created themselves, so a task handed
+/// up to the lead stays in view of whoever handed it up. A task across units is a delegation
+/// to the other unit's lead — the address book decides that, not this.</para>
+///
+/// <para><b>Without units nothing changes:</b> there is one board, and everyone sees it.</para>
+/// </summary>
+public static class TaskBoard
+{
+    /// <summary>The unit whose board the task is on; <c>null</c> for the top level.</summary>
+    public static string? UnitOf(TaskItem task, OrgChart org)
+    {
+        var assigned = TaskAssignee.AgentId(task.Assignee);
+        if (assigned.Length > 0 && org.Agent(assigned) is not null)
+            return org.UnitOf(assigned)?.Id;
+
+        if (!string.IsNullOrWhiteSpace(task.CreatedBy) && org.Agent(task.CreatedBy) is not null)
+            return org.UnitOf(task.CreatedBy)?.Id;
+
+        return null;
+    }
+
+    /// <summary>
+    /// What an agent may see — <c>null</c> for "everything": without units, without an
+    /// organisation (outside the engine), or for an agent the organisation does not know.
+    /// </summary>
+    public static Func<TaskItem, bool>? VisibleTo(OrgChart? org, string agentId)
+    {
+        if (org is not { HasUnits: true } || org.Agent(agentId) is null)
+            return null;
+
+        var boards = BoardsOf(org, agentId);
+        var topLevel = org.UnitOf(agentId) is null;
+
+        return task =>
+            string.Equals(task.CreatedBy, agentId, StringComparison.OrdinalIgnoreCase)
+            || (UnitOf(task, org) is { } unit ? boards.Contains(unit) : topLevel);
+    }
+
+    /// <summary>The units whose boards an agent sees: its own, and all below the unit it leads.</summary>
+    public static IReadOnlySet<string> BoardsOf(OrgChart org, string agentId)
+    {
+        var boards = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        if (org.UnitOf(agentId) is { } own)
+            boards.Add(own.Id);
+
+        if (org.LedBy(agentId) is { } led)
+        {
+            var seen = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            var pending = new Stack<string>();
+            pending.Push(led.Id);
+            while (pending.TryPop(out var unitId))
+            {
+                if (!seen.Add(unitId))
+                    continue; // a broken tree must not hang this
+                boards.Add(unitId);
+                foreach (var child in org.Children(unitId))
+                    pending.Push(child.Id);
+            }
+        }
+        return boards;
+    }
+}

src/ClawdDotNet.Core/Tasks/TaskFrontmatter.cs

@@ -152,6 +152,7 @@ public static class TaskFrontmatter
             OnlyWhenMarketOpen = ParseBool(scalars.GetValueOrDefault("onlyWhenMarketOpen")),
             ToolName = scalars.GetValueOrDefault("tool_name", ""),
             JobTypeId = scalars.GetValueOrDefault("job_type", ""),
+            CreatedBy = scalars.GetValueOrDefault("created_by", ""),
             Body = body
         };
         return true;
@@ -169,6 +170,8 @@ public static class TaskFrontmatter
         sb.Append($"type: {TaskText.Of(task.Type)}\n");
         sb.Append($"priority: {Math.Clamp(task.Priority, 1, 5)}\n");
         sb.Append($"assignee: {Scalar(task.Assignee)}\n");
+        if (!string.IsNullOrWhiteSpace(task.CreatedBy))
+            sb.Append($"created_by: {Scalar(task.CreatedBy)}\n");
 
         if (task.When is { } w)
         {

src/ClawdDotNet.Core/Tasks/TaskModels.cs

@@ -228,6 +228,13 @@ public sealed record TaskItem
     /// </summary>
     public bool CatchUpPending { get; init; }
 
+    /// <summary>
+    /// #684: The agent that created the task; empty for tasks from a human, from a file
+    /// written by hand, or from before this field. Decides the board of a task nobody in
+    /// particular is assigned to — see <see cref="TaskBoard"/>.
+    /// </summary>
+    public string CreatedBy { get; init; } = "";
+
     /// <summary>A one-time task that was refused for lack of budget and carried over.</summary>
     public bool IsCarriedOver => !IsRecurring && BudgetMissCount > 0;
 
@@ -269,4 +276,24 @@ public sealed record TaskQuery
     public bool IncludeArchived { get; init; }
 
     public int Limit { get; init; } = 50;
+
+    /// <summary>
+    /// #684: The same filter as the repository's query, for a list that is already in
+    /// memory — when a board has to be filtered first and the database cannot do that.
+    /// </summary>
+    public bool Matches(TaskItem task)
+    {
+        if (Status is { } status ? task.Status != status : !IncludeArchived && task.Status == TaskItemStatus.Archived)
+            return false;
+        if (!string.IsNullOrWhiteSpace(Assignee) && !string.Equals(task.Assignee, Assignee.Trim(), StringComparison.OrdinalIgnoreCase))
+            return false;
+        if (!string.IsNullOrWhiteSpace(Search))
+        {
+            var search = Search.Trim();
+            if (!task.Title.Contains(search, StringComparison.OrdinalIgnoreCase)
+                && !task.Body.Contains(search, StringComparison.OrdinalIgnoreCase))
+                return false;
+        }
+        return true;
+    }
 }

src/ClawdDotNet.Core/Tasks/TaskboardService.cs

@@ -31,7 +31,28 @@ public sealed class TaskboardService
     public Task<IReadOnlyList<TaskItem>> ListAsync(TaskQuery query, CancellationToken ct)
         => _repo.ListAsync(query, ct);
 
-    /// <summary>The whole board, without the cap of <see cref="ListAsync"/>.</summary>
+    /// <summary>
+    /// #684: A list restricted to what one agent may see. The boards cannot be expressed in
+    /// the database query — they follow from the organisation — so the whole board is read
+    /// and filtered here, then capped: filtering after the database's cap would silently
+    /// drop tasks of the own unit behind those of others.
+    /// </summary>
+    public async Task<IReadOnlyList<TaskItem>> ListAsync(TaskQuery query, Func<TaskItem, bool>? visible, CancellationToken ct)
+    {
+        if (visible is null)
+            return await _repo.ListAsync(query, ct);
+
+        var all = await _repo.ListAllAsync(query.IncludeArchived || query.Status == TaskItemStatus.Archived, ct);
+        return all
+            .Where(visible)
+            .Where(query.Matches)
+            .OrderByDescending(t => t.Priority)
+            .ThenByDescending(t => t.UpdatedAt)
+            .Take(Math.Clamp(query.Limit, 1, 500))
+            .ToList();
+    }
+
+    /// <summary>The whole board, without the cap of <see cref="ListAsync(TaskQuery, CancellationToken)"/>.</summary>
     public Task<IReadOnlyList<TaskItem>> ListAllAsync(CancellationToken ct, bool includeArchived = false)
         => _repo.ListAllAsync(includeArchived, ct);
 

src/ClawdDotNet.Manager.Web/wwwroot/app.css

@@ -2372,3 +2372,8 @@ tr.org-ausreisser td {
 @media (max-width: 900px) {
   .org-raster { grid-template-columns: 1fr; }
 }
+
+/* #684: the board filter above the task cards */
+.taskboard-bretter {
+  margin-bottom: 12px;
+}

src/ClawdDotNet.Manager.Web/wwwroot/i18n/de.json

@@ -346,6 +346,9 @@
   "tasks.budgetMissedLast": "zuletzt {time}",
   "tasks.budgetCarriedOver": "mitgenommen, wieder fällig ab {time}",
   "tasks.budgetCatchUp": "ein Nachholauf ab {time}",
+  "tasks.board": "Brett",
+  "tasks.boardAll": "Alle Bretter",
+  "tasks.boardTopLevel": "Oberste Ebene",
 
   "services.title": "Dienste",
   "services.newService": "Neuer Dienst",

src/ClawdDotNet.Manager.Web/wwwroot/i18n/en.json

@@ -346,6 +346,9 @@
   "tasks.budgetMissedLast": "last at {time}",
   "tasks.budgetCarriedOver": "carried over, due again from {time}",
   "tasks.budgetCatchUp": "one catch-up run from {time}",
+  "tasks.board": "Board",
+  "tasks.boardAll": "All boards",
+  "tasks.boardTopLevel": "Top level",
 
   "services.title": "Services",
   "services.newService": "New Service",

src/ClawdDotNet.Manager.Web/wwwroot/views/tasks.js

@@ -58,6 +58,9 @@ const ABGESCHLOSSEN = ["Done", "Canceled", "Archived"];
 
 let zeigeAbgeschlossene = false;
 
+/** #684: The board shown — "" for all, "-" for the top level, otherwise a unit id. */
+let brettFilter = "";
+
 export async function rendereAufgaben() {
   const container = document.getElementById("ansicht-inhalt");
   if (!container) return;
@@ -114,9 +117,14 @@ async function ladeTaskboard() {
 
   try {
     const alle = (await api("/tasks?limit=200")) || [];
-    const tasks = alle.filter((t) => zeigeAbgeschlossene || !ABGESCHLOSSEN.includes(t.status));
+    const offen = alle.filter((t) => zeigeAbgeschlossene || !ABGESCHLOSSEN.includes(t.status));
+    const tasks = offen.filter((t) => !brettFilter || (brettFilter === "-" ? !t.board : t.board === brettFilter));
     container.replaceChildren();
 
+    // #684: With units, every task is on a unit's board — pick one to see only that.
+    const bretter = brettAuswahl(alle);
+    if (bretter) container.append(bretter);
+
     if (tasks.length === 0) {
       container.append(
         erstelleKarte(t("tasks.empty"), [
@@ -141,6 +149,30 @@ async function ladeTaskboard() {
   }
 }
 
+/**
+ * #684: The boards the tasks are on, as a filter. Built from the tasks themselves, so it
+ * shows only boards that hold something; absent when no task is on a unit's board.
+ */
+function brettAuswahl(tasks) {
+  const bretter = new Map();
+  for (const task of tasks) if (task.board) bretter.set(task.board, task.boardPath || task.board);
+  if (bretter.size === 0) return null;
+
+  const auswahl = erstelleElement("select", {
+    "aria-label": t("tasks.board"),
+    onchange: (e) => { brettFilter = e.target.value; ladeTaskboard(); }
+  },
+  erstelleElement("option", { value: "", text: t("tasks.boardAll") }),
+  erstelleElement("option", { value: "-", text: t("tasks.boardTopLevel") }),
+  ...[...bretter.entries()]
+    .sort((a, b) => a[1].localeCompare(b[1]))
+    .map(([id, pfad]) => erstelleElement("option", { value: id, text: pfad })));
+  auswahl.value = brettFilter;
+
+  return erstelleElement("label", { klasse: "gruppe-horizontal text-klein taskboard-bretter" },
+    erstelleElement("span", { text: t("tasks.board") }), auswahl);
+}
+
 function terminText(task) {
   if (!task.when) return t("tasks.scheduleNone");
   const art = task.when.kind;
@@ -155,7 +187,10 @@ function erstelleAufgabenKarte(task) {
       "div",
       { klasse: "task-status-zeile gruppe-horizontal" },
       erstellePlakette(holeStatusText(task.status), STATUS_ART[task.status] || "neutral"),
-      erstelleElement("span", { klasse: "gedaempft text-klein", text: `${task.id} · ${task.assignee || "—"}` })
+      erstelleElement("span", {
+        klasse: "gedaempft text-klein",
+        text: `${task.id} · ${task.assignee || "—"}${task.boardPath ? ` · ▤ ${task.boardPath}` : ""}`
+      })
     )
   );
 

src/ClawdDotNet.Tools.Taskboard/TaskboardTool.cs

@@ -22,7 +22,8 @@ public sealed class TaskboardTool : IAgentTool
     public string Name => "Taskboard";
 
     public string Description => """
-        The shared taskboard — persists across runs and restarts.
+        The taskboard — persists across runs and restarts. If your instance has units, you
+        see your unit's board; a lead also sees the boards of the units below.
 
         Use it to track and distribute work instead of keeping it in context:
         own open items, assignments to other agents, recurring schedules.
@@ -157,15 +158,18 @@ public sealed class TaskboardTool : IAgentTool
             && CheckAssignee(GetString(input, "assignee"), context) is { } outOfReach)
             return ToolResult.Fail(outOfReach);
 
+        // #684: The boards this agent sees; null means all of them (no units).
+        var visible = TaskBoard.VisibleTo(context.Organisation, context.AgentId);
+
         try
         {
             return action switch
             {
-                "task_create" => await CreateAsync(input, board, context.AgentId, ct),
-                "task_find" => await FindAsync(input, board, ct),
-                "task_list" => await ListAsync(input, board, ct),
-                "task_update" => await UpdateAsync(input, board, ct),
-                "task_comment" => await CommentAsync(input, board, context.AgentId, ct),
+                "task_create" => await CreateAsync(input, board, context.AgentId, visible, ct),
+                "task_find" => await FindAsync(input, board, visible, ct),
+                "task_list" => await ListAsync(input, board, visible, ct),
+                "task_update" => await UpdateAsync(input, board, visible, ct),
+                "task_comment" => await CommentAsync(input, board, context.AgentId, visible, ct),
                 _ => ToolResult.Fail($"Unknown action: {action}")
             };
         }
@@ -206,13 +210,13 @@ public sealed class TaskboardTool : IAgentTool
     /// the first sentence.</para>
     /// </summary>
     private static async Task<ToolResult> FindAsync(
-        JsonElement input, TaskboardService board, CancellationToken ct)
+        JsonElement input, TaskboardService board, Func<TaskItem, bool>? visible, CancellationToken ct)
     {
         var title = GetString(input, "title") ?? GetString(input, "search");
         if (string.IsNullOrWhiteSpace(title))
             return ToolResult.Fail("'title' is required — what should be searched for?");
 
-        var treffer = await SucheAehnlicheAsync(board, title, null, ct);
+        var treffer = await SucheAehnlicheAsync(board, title, null, visible, ct);
         if (treffer.Count == 0)
             return ToolResult.Ok($"No open task resembles \"{title.Trim()}\". You can create it with task_create.");
 
@@ -232,18 +236,29 @@ public sealed class TaskboardTool : IAgentTool
         return ToolResult.Ok(sb.ToString());
     }
 
-    /// <summary>Offene Aufgaben mit verwandtem Titel, engste zuerst.</summary>
+    /// <summary>
+    /// Offene Aufgaben mit verwandtem Titel, engste zuerst — nur auf den Brettern, die der
+    /// Agent sieht (#684). Eine aehnliche Aufgabe der Buchhaltung haelt keine Marketing-Aufgabe
+    /// auf, und die Ablehnung verraete sonst, was dort liegt.
+    /// </summary>
     private static async Task<List<(TaskItem Task, TaskTitleMatch Match)>> SucheAehnlicheAsync(
-        TaskboardService board, string title, string? exceptId, CancellationToken ct)
+        TaskboardService board, string title, string? exceptId, Func<TaskItem, bool>? visible, CancellationToken ct)
     {
         // Uncapped (#716): with a limit of 500, a duplicate among older, low-priority tasks
         // stayed invisible once the board grew beyond that.
         var alle = await board.ListAllAsync(ct);
-        return TaskSimilarity.FindOpen(alle, title, exceptId);
+        return TaskSimilarity.FindOpen(visible is null ? alle : alle.Where(visible).ToList(), title, exceptId);
     }
 
+    /// <summary>
+    /// #684: A task on a board the agent does not see is answered like one that does not
+    /// exist — the answer must not tell that it is there.
+    /// </summary>
+    private static async Task<bool> CanSeeAsync(TaskboardService board, string id, Func<TaskItem, bool>? visible, CancellationToken ct)
+        => visible is null || (await board.GetAsync(id, ct) is { } task && visible(task));
+
     private static async Task<ToolResult> CreateAsync(
-        JsonElement input, TaskboardService board, string author, CancellationToken ct)
+        JsonElement input, TaskboardService board, string author, Func<TaskItem, bool>? visible, CancellationToken ct)
     {
         var title = GetString(input, "title");
         if (string.IsNullOrWhiteSpace(title))
@@ -256,7 +271,7 @@ public sealed class TaskboardTool : IAgentTool
         // existing one — so that later one can see how often and for how long.
         if (GetBool(input, "force") != true)
         {
-            var dublette = (await SucheAehnlicheAsync(board, title, null, ct))
+            var dublette = (await SucheAehnlicheAsync(board, title, null, visible, ct))
                 .FirstOrDefault(t => t.Match == TaskTitleMatch.Duplicate).Task;
 
             if (dublette is not null)
@@ -285,7 +300,9 @@ public sealed class TaskboardTool : IAgentTool
             RequireApproval = GetBool(input, "require_approval") ?? false,
             Acceptance = GetString(input, "acceptance")?.Trim() ?? "",
             BlockedBy = GetStringList(input, "blocked_by"),
-            OnlyWhenMarketOpen = GetBool(input, "onlyWhenMarketOpen") ?? false
+            OnlyWhenMarketOpen = GetBool(input, "onlyWhenMarketOpen") ?? false,
+            // #684: decides the board when the task is for a human or a fresh run.
+            CreatedBy = author
         };
 
         var created = await board.CreateAsync(definition, ct);
@@ -296,7 +313,7 @@ public sealed class TaskboardTool : IAgentTool
     }
 
     private static async Task<ToolResult> ListAsync(
-        JsonElement input, TaskboardService board, CancellationToken ct)
+        JsonElement input, TaskboardService board, Func<TaskItem, bool>? visible, CancellationToken ct)
     {
         var query = new TaskQuery
         {
@@ -306,7 +323,7 @@ public sealed class TaskboardTool : IAgentTool
             Limit = GetInt(input, "limit") ?? 50
         };
 
-        var tasks = await board.ListAsync(query, ct);
+        var tasks = await board.ListAsync(query, visible, ct);
         if (tasks.Count == 0)
             return ToolResult.Ok("No matching tasks.");
 
@@ -314,11 +331,13 @@ public sealed class TaskboardTool : IAgentTool
     }
 
     private static async Task<ToolResult> UpdateAsync(
-        JsonElement input, TaskboardService board, CancellationToken ct)
+        JsonElement input, TaskboardService board, Func<TaskItem, bool>? visible, CancellationToken ct)
     {
         var id = GetString(input, "id");
         if (string.IsNullOrWhiteSpace(id))
             return ToolResult.Fail("'id' is required.");
+        if (!await CanSeeAsync(board, id.Trim(), visible, ct))
+            return ToolResult.Fail($"No task found with ID '{id}'.");
 
         if (!TryReadWhen(input, out var when, out var whenError))
             return ToolResult.Fail(whenError!);
@@ -348,11 +367,13 @@ public sealed class TaskboardTool : IAgentTool
     }
 
     private static async Task<ToolResult> CommentAsync(
-        JsonElement input, TaskboardService board, string author, CancellationToken ct)
+        JsonElement input, TaskboardService board, string author, Func<TaskItem, bool>? visible, CancellationToken ct)
     {
         var id = GetString(input, "id");
         if (string.IsNullOrWhiteSpace(id))
             return ToolResult.Fail("'id' is required.");
+        if (!await CanSeeAsync(board, id.Trim(), visible, ct))
+            return ToolResult.Fail($"No task found with ID '{id}'.");
 
         var text = GetString(input, "text");
         if (string.IsNullOrWhiteSpace(text))

src/ClawdDotNet.Web/Contracts/Dtos.cs

@@ -117,7 +117,11 @@ public sealed record TaskDto(
     DateTime? NextRunUtc = null,
     TaskLastRunDto? LastRun = null,
     string? Hinweis = null,
-    TaskBudgetMissDto? BudgetMiss = null);
+    TaskBudgetMissDto? BudgetMiss = null,
+    string? CreatedBy = null,
+    // #684: the unit whose board the task is on, computed from the organisation; null on the top level.
+    string? Board = null,
+    string? BoardPath = null);
 
 /// <summary>
 /// #716: Runs of this task the budget refused — only present while something is open

src/ClawdDotNet.Web/Contracts/Mapping.cs

@@ -153,7 +153,16 @@ internal static class Mapping
             BudgetMiss: task.BudgetMissCount > 0 || task.CatchUpPending || task.DeferredUntil is not null
                 ? new TaskBudgetMissDto(task.BudgetMissCount, task.LastBudgetMissAt, task.DeferredUntil,
                     task.CatchUpPending, task.IsCarriedOver)
-                : null);
+                : null,
+            CreatedBy: string.IsNullOrWhiteSpace(task.CreatedBy) ? null : task.CreatedBy);
+
+    /// <summary>#684: The board of a task, for a list the human sees whole.</summary>
+    public static TaskDto WithBoard(this TaskDto dto, TaskItem task, Core.Organisation.OrgChart org)
+    {
+        if (!org.HasUnits || Core.Tasks.TaskBoard.UnitOf(task, org) is not { } unit)
+            return dto;
+        return dto with { Board = unit, BoardPath = org.PathOf(unit) };
+    }
 
     /// <summary>
     /// Ein wartender Aufruf samt seiner eingefrorenen Argumente.

src/ClawdDotNet.Web/Endpoints/ApiEndpoints.cs

@@ -260,9 +260,14 @@ internal static class ApiEndpoints
         // #594: Das Taskboard ist die einzige Stelle fuer geplante Arbeit. Die frueheren
         // /api/jobs bearbeiteten die Alt-Konfiguration, die nach der Uebernahme nichts mehr bewirkte.
         tasks.MapGet("/", async (AppHost host, CancellationToken ct, int limit = 50) =>
-            await host.TaskAdmin.ListAsync(limit, ct) is { } list
-                ? Results.Ok(list.Select(t => t.ToDto()).ToList())
-                : Unavailable("Kein Taskboard: Den Agenten dieser Instanz fehlt ein gemeinsamer Arbeitsbereich."));
+        {
+            if (await host.TaskAdmin.ListAsync(limit, ct) is not { } list)
+                return Unavailable("Kein Taskboard: Den Agenten dieser Instanz fehlt ein gemeinsamer Arbeitsbereich.");
+
+            // #684: A human sees every board; each task says which one it is on.
+            var org = host.Organisation.Current();
+            return Results.Ok(list.Select(t => t.ToDto().WithBoard(t.Task, org)).ToList());
+        });
 
         tasks.MapPost("/", async (AppHost host, TaskInputDto input, CancellationToken ct) =>
             (await host.TaskAdmin.CreateAsync(input.ToInput(), ct)).ToResponse());

tests/ClawdDotNet.Tools.Tests/Taskboard/UnitBoardTests.cs

@@ -0,0 +1,186 @@
+using System.Text.Json;
+using ClawdDotNet.Core.Config;
+using ClawdDotNet.Core.Organisation;
+using ClawdDotNet.Core.Storage;
+using ClawdDotNet.Core.Tasks;
+using ClawdDotNet.Core.Tools;
+using ClawdDotNet.Tools.Taskboard;
+using ClawdDotNet.Tools.Tests.FileRW;
+using Microsoft.Extensions.Logging.Abstractions;
+using Shouldly;
+
+namespace ClawdDotNet.Tools.Tests.Taskboard;
+
+/// <summary>
+/// #684: One board per unit. The bookkeeper's tasks do not show up for marketing, do not
+/// hold up a marketing task as a "duplicate", and cannot be commented on from outside.
+///
+/// <code>
+/// marketing (lead: marketing-lead)
+/// └── amazon (lead: amazon-lead) · ads
+/// accounting (lead: accounting-lead) · bookkeeper
+/// ceo on the top level
+/// </code>
+/// </summary>
+public sealed class UnitBoardTests : IDisposable
+{
+    private readonly string _directory;
+    private readonly SqliteStorage _storage;
+    private readonly SqliteTaskRepository _repo;
+    private readonly TaskboardTool _tool = new();
+
+    private readonly List<AgentConfig> _agents =
+    [
+        new() { AgentId = "ceo" },
+        new() { AgentId = "marketing-lead", UnitId = "marketing" },
+        new() { AgentId = "amazon-lead", UnitId = "amazon" },
+        new() { AgentId = "ads", UnitId = "amazon" },
+        new() { AgentId = "accounting-lead", UnitId = "accounting" },
+        new() { AgentId = "bookkeeper", UnitId = "accounting" }
+    ];
+
+    private readonly List<UnitConfig> _units =
+    [
+        new() { Id = "marketing", Name = "Marketing", LeaderAgentId = "marketing-lead" },
+        new() { Id = "amazon", Name = "Amazon", ParentId = "marketing", LeaderAgentId = "amazon-lead" },
+        new() { Id = "accounting", Name = "Accounting", LeaderAgentId = "accounting-lead" }
+    ];
+
+    public UnitBoardTests()
+    {
+        _directory = Path.Combine(Path.GetTempPath(), "clawd-tests", Guid.NewGuid().ToString("N"));
+        _storage = new SqliteStorage(Path.Combine(_directory, "state.db"));
+        _repo = new SqliteTaskRepository(_storage);
+    }
+
+    public void Dispose()
+    {
+        SqliteStorage.ReleasePooledConnections(_directory);
+        try { Directory.Delete(_directory, recursive: true); }
+        catch { /* cleanup is secondary */ }
+    }
+
+    private string TasksDir => Path.Combine(_directory, "SharedWorkspace", "tasks");
+
+    private async Task<ToolResult> Run(string agentId, object input, bool withUnits = true)
+    {
+        var context = new AgentToolContext(
+            agentId, "inst", new Dictionary<string, object?>(), new NullStateStore(), NullLogger.Instance,
+            CancellationToken.None, SharedWorkspacePath: Path.Combine(_directory, "SharedWorkspace"), Tasks: _repo)
+        {
+            Organisation = withUnits ? new OrgChart(_units, _agents) : new OrgChart([], _agents)
+        };
+        return await _tool.ExecuteAsync(JsonSerializer.SerializeToElement(input), context, CancellationToken.None);
+    }
+
+    private async Task<string> Create(string agentId, string title, string assignee = "@human")
+    {
+        var result = await Run(agentId, new { action = "task_create", title, assignee, force = true });
+        result.Success.ShouldBeTrue(result.ErrorMessage);
+        return result.Content.Split(' ', 4)[2]; // "Task created: <id> — …"
+    }
+
+    private async Task<string> List(string agentId, bool withUnits = true)
+        => (await Run(agentId, new { action = "task_list" }, withUnits)).Content;
+
+    [Fact]
+    public async Task Each_unit_sees_its_own_board()
+    {
+        await Create("bookkeeper", "Book the invoices of September");
+        await Create("ads", "Raise the bid for chairs");
+
+        var marketing = await List("ads");
+        var accounting = await List("bookkeeper");
+
+        marketing.ShouldContain("Raise the bid");
+        marketing.ShouldNotContain("invoices");
+        accounting.ShouldContain("invoices");
+        accounting.ShouldNotContain("Raise the bid");
+    }
+
+    [Fact]
+    public async Task A_lead_also_sees_the_boards_of_the_units_below()
+    {
+        await Create("ads", "Raise the bid for chairs");
+        await Create("bookkeeper", "Book the invoices of September");
+
+        var lead = await List("marketing-lead");
+
+        lead.ShouldContain("Raise the bid", Case.Sensitive, "amazon lies below marketing");
+        lead.ShouldNotContain("invoices");
+    }
+
+    [Fact]
+    public async Task A_task_handed_up_stays_in_view_of_whoever_handed_it_up()
+    {
+        // amazon-lead's lead is marketing-lead — the task lands on marketing's board …
+        await Create("amazon-lead", "Approve the new budget", "@marketing-lead");
+
+        (await List("marketing-lead")).ShouldContain("Approve the new budget");
+        // … and the one who created it still sees it, although amazon's board does not hold it.
+        (await List("amazon-lead")).ShouldContain("Approve the new budget");
+        (await List("ads")).ShouldNotContain("Approve the new budget");
+    }
+
+    [Fact]
+    public async Task A_similar_task_on_another_board_is_no_duplicate()
+    {
+        await Create("bookkeeper", "Check the supplier invoice");
+
+        var result = await Run("ads", new { action = "task_create", title = "Check the supplier invoice" });
+
+        result.Success.ShouldBeTrue(result.ErrorMessage);
+        result.Content.ShouldNotContain("Observed again");
+        (await Run("bookkeeper", new { action = "task_find", title = "Check the supplier invoice" })).Content
+            .ShouldContain("1 open task(s)", Case.Sensitive, "and nothing was written onto the bookkeeper's task");
+    }
+
+    [Fact]
+    public async Task A_task_on_another_board_cannot_be_changed_or_commented_on()
+    {
+        var id = await Create("bookkeeper", "Book the invoices of September");
+
+        var update = await Run("ads", new { action = "task_update", id, status = "canceled" });
+        var comment = await Run("ads", new { action = "task_comment", id, text = "not needed" });
+        var unknown = await Run("ads", new { action = "task_comment", id = "t-does-not-exist", text = "x" });
+
+        update.Success.ShouldBeFalse();
+        comment.Success.ShouldBeFalse();
+        comment.ErrorMessage!.Replace(id, "X").ShouldBe(unknown.ErrorMessage!.Replace("t-does-not-exist", "X"),
+            "the same answer as for a task that does not exist");
+        (await _repo.GetAsync(id, default))!.Status.ShouldBe(TaskItemStatus.Todo);
+    }
+
+    [Fact]
+    public async Task An_open_task_moves_with_its_agent()
+    {
+        await Create("amazon-lead", "Prepare the listing", "@ads");
+        (await List("bookkeeper")).ShouldNotContain("Prepare the listing");
+
+        _agents.Single(a => a.AgentId == "ads").UnitId = "accounting";
+
+        (await List("bookkeeper")).ShouldContain("Prepare the listing", Case.Sensitive, "the board follows the assignee");
+    }
+
+    [Fact]
+    public async Task Without_units_there_is_one_board_for_everyone()
+    {
+        await Create("bookkeeper", "Book the invoices of September");
+
+        (await List("ads", withUnits: false)).ShouldContain("invoices");
+    }
+
+    [Fact]
+    public async Task The_creator_is_kept_in_the_file_and_survives_a_re_import()
+    {
+        var id = await Create("ads", "Raise the bid for chairs");
+        var file = Directory.GetFiles(TasksDir).Single();
+        File.ReadAllText(file).ShouldContain("created_by: ads");
+
+        // A file written by hand without the field keeps what the database knows.
+        File.WriteAllText(file, File.ReadAllText(file).Replace("created_by: ads\n", "").Replace("created_by: ads\r\n", ""));
+        await new TaskboardService(_repo, TasksDir).ImportAllAsync(default);
+
+        (await _repo.GetAsync(id, default))!.CreatedBy.ShouldBe("ads");
+    }
+}