diff --git a/docs/explore-notes/external-mcp.md b/docs/explore-notes/external-mcp.md
index f74131a0..9795f50d 100644
--- a/docs/explore-notes/external-mcp.md
+++ b/docs/explore-notes/external-mcp.md
@@ -32,7 +32,14 @@ session internals, or app-settings writes. Auth via an optional `X-ClaudeDo-Key`
      `ListTasksResult`/`BatchGetTaskResult`, where exactly one of the lean (`TaskRefDto`) and
      full (`TaskDto`, incl. Description/Result) fields is populated per the flag — keeps a
      list of verbosely-described tasks from blowing past the response size limit by default.
-3. `ExternalMcpExceptionFilter.Wrap` is registered as a call-tool filter so
+3. **Description style is documented in `McpToolDocs`** (same folder) and shared boilerplate
+   lives there as `const` strings. Rules: the first sentence says what the tool does *and* when
+   to reach for it (MCP clients rank tools by that text, so the trigger must not sit behind
+   return-shape prose); parameters are documented with `[Description]` **on the parameter**, not
+   in the tool description; result fields appear only where the caller must branch on them
+   before calling (`isEmpty`, `truncated`, `conflicts`, `available`); no design rationale or
+   "since this feature was introduced" history. Not test-enforced — review it in PRs.
+4. `ExternalMcpExceptionFilter.Wrap` is registered as a call-tool filter so
    `InvalidOperationException` / `ArgumentException` messages survive as `McpException` —
    otherwise the SDK's catch-all replaces any non-`McpException` with a generic
    *"An error occurred invoking 'X'."*
@@ -42,8 +49,9 @@ session internals, or app-settings writes. Auth via an optional `X-ClaudeDo-Key`
 ### `ExternalMcpService` — task CRUD, execution, git
 
 Task: `ListTaskLists`, `ListTasks`, `GetTask`, `AddTask`, `AddSubtask`, `UpdateTask`,
-`UpdateTaskStatus`, `GetTaskStatusValues`, `ReviewTask`, `RunTaskNow`, `ContinueTask`,
-`CancelTask`, `DeleteTask`.
+`UpdateTaskStatus`, `ReviewTask`, `RunTaskNow`, `ContinueTask`, `CancelTask`, `DeleteTask`.
+(`GetTaskStatusValues` was removed — a whole tool entry for static reference text. `GetTask`'s
+description is now the canonical place for what each status means.)
 
 Worktree/git: `GetTaskWorktree`, `GetTaskDiff`, `MergeTask`, `ContinueMerge`, `AbortMerge`,
 `PreviewMerge`, `PreviewMergeSet`, `RevertMerge`, `ListWorktrees`, `CleanupTaskWorktree`.
diff --git a/src/ClaudeDo.Worker/CLAUDE.md b/src/ClaudeDo.Worker/CLAUDE.md
index 35fc3ca5..899d5460 100644
--- a/src/ClaudeDo.Worker/CLAUDE.md
+++ b/src/ClaudeDo.Worker/CLAUDE.md
@@ -48,7 +48,7 @@ subfolder within their area; the namespace stays the area namespace.
 - **RunCancellationRegistry** — taskId → running-run CTS. Lets `TaskStateService.CancelAsync` kill a cancelled task's process without a DI cycle.
 - **OverrideSlotService** — owns `RunNow` / `ContinueTask`; goes through `TaskStateService.StartRunningAsync` (caller-driven, serialized by slot lock).
 - **StaleTaskRecovery** — startup-only; calls `TaskStateService.RecoverStaleRunningAsync` to flip orphaned `Running` rows to `Failed`.
-- **External/*** — always-on MCP tools for general Claude sessions, scoped to *starting* and *observing* sessions (no multi-turn, planning internals, or app-settings writes). Auth via optional `X-ClaudeDo-Key`. **Two hard conventions** (both test-enforced): every optional parameter needs a C# default value, and no tool returns bare `Task`/a nullable payload. Full tool inventory + per-tool behaviour → [external-mcp](../../docs/explore-notes/external-mcp.md).
+- **External/*** — always-on MCP tools for general Claude sessions, scoped to *starting* and *observing* sessions (no multi-turn, planning internals, or app-settings writes). Auth via optional `X-ClaudeDo-Key`. **Two hard conventions** (both test-enforced): every optional parameter needs a C# default value, and no tool returns bare `Task`/a nullable payload. **Tool-description style** (not test-enforced) is documented in `External/McpToolDocs.cs`, which also holds the shared boilerplate clauses — read it before adding or editing a tool description. Full tool inventory + per-tool behaviour → [external-mcp](../../docs/explore-notes/external-mcp.md).
 
 ## Status Model
 
diff --git a/src/ClaudeDo.Worker/External/AgentMcpTools.cs b/src/ClaudeDo.Worker/External/AgentMcpTools.cs
index 80509602..66502d2e 100644
--- a/src/ClaudeDo.Worker/External/AgentMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/AgentMcpTools.cs
@@ -12,7 +12,7 @@ public sealed class AgentMcpTools
 
     public AgentMcpTools(AgentFileService agents) => _agents = agents;
 
-    [McpServerTool, Description("List available agent definition files (name, description, path) for use as a task's agent path.")]
+    [McpServerTool, Description("List available agent definition files (name, description, path) to pick a value for a task's or list's agentPath override.")]
     public async Task<IReadOnlyList<AgentInfo>> ListAgents(CancellationToken cancellationToken)
         => await _agents.ScanAsync(cancellationToken);
 }
diff --git a/src/ClaudeDo.Worker/External/AppSettingsMcpTools.cs b/src/ClaudeDo.Worker/External/AppSettingsMcpTools.cs
index b7c8c72f..82f3ab90 100644
--- a/src/ClaudeDo.Worker/External/AppSettingsMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/AppSettingsMcpTools.cs
@@ -19,7 +19,7 @@ public sealed class AppSettingsMcpTools
 
     public AppSettingsMcpTools(IDbContextFactory<ClaudeDoDbContext> dbFactory) => _dbFactory = dbFactory;
 
-    [McpServerTool, Description("Read the worker's app-level defaults (model, max turns, permission mode, max parallel execution slots, worktree strategy). Read-only.")]
+    [McpServerTool, Description("Read the worker's global defaults (model, max turns, permission mode, max parallel execution slots, worktree strategy) that apply when a task/list doesn't override them. Read-only.")]
     public async Task<AppSettingsReadDto> GetAppSettings(CancellationToken cancellationToken)
     {
         using var ctx = await _dbFactory.CreateDbContextAsync(cancellationToken);
diff --git a/src/ClaudeDo.Worker/External/AttachmentMcpTools.cs b/src/ClaudeDo.Worker/External/AttachmentMcpTools.cs
index b387f09a..dd1096c7 100644
--- a/src/ClaudeDo.Worker/External/AttachmentMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/AttachmentMcpTools.cs
@@ -33,17 +33,15 @@ public sealed class AttachmentMcpTools
     }
 
     [McpServerTool, Description(
-        "Attach a read-only reference file to a task. These files are handed to the agent at run time, " +
-        "making them useful to prepare context for a task that will run later (e.g. plans, scripts, specs). " +
-        "Pass textContent for plain-text files (plans, markdown, scripts). " +
-        "Pass base64Content only for binary files (images, archives). Exactly one of the two must be provided. " +
-        "Re-attaching a file with the same fileName overwrites the previous version. " +
-        "Refuses if the task is currently Running — cancel it first.")]
+        "Attach a read-only reference file to a task so the agent receives it at run time — use to prepare " +
+        "context (plans, scripts, specs) for a task that will run later. Exactly one of textContent/" +
+        "base64Content is required. Re-attaching the same fileName overwrites the previous version." +
+        McpToolDocs.NotWhileRunning)]
     public async Task<AttachmentDto> AddTaskAttachment(
         string taskId,
-        string fileName,
-        string? textContent = null,
-        string? base64Content = null,
+        [Description("Name to store the attachment under; reusing an existing name overwrites it.")] string fileName,
+        [Description("Plain-text content (plans, markdown, scripts). Provide this or base64Content, not both.")] string? textContent = null,
+        [Description("Base64-encoded content for binary files (images, archives). Provide this or textContent, not both.")] string? base64Content = null,
         CancellationToken ct = default)
     {
         var task = await _tasks.GetByIdAsync(taskId, ct)
@@ -94,7 +92,8 @@ public sealed class AttachmentMcpTools
         return new AttachmentDto(fileName, byteSize, existing?.CreatedAt ?? DateTime.UtcNow);
     }
 
-    [McpServerTool, Description("List all attachments on a task (fileName, byteSize, createdAt).")]
+    [McpServerTool, Description(
+        "List all attachments on a task — use to check what reference files are already attached before adding more.")]
     public async Task<IReadOnlyList<AttachmentDto>> ListTaskAttachments(
         string taskId, CancellationToken ct = default)
     {
@@ -103,8 +102,8 @@ public sealed class AttachmentMcpTools
     }
 
     [McpServerTool, Description(
-        "Remove a single attachment from a task. Deletes both the file on disk and the database record. " +
-        "Refuses if the task is currently Running — cancel it first. Returns { removed: true, taskId, fileName } on success.")]
+        "Remove a single attachment from a task, deleting both the file on disk and its database record." +
+        McpToolDocs.NotWhileRunning)]
     public async Task<RemoveAttachmentResult> RemoveTaskAttachment(
         string taskId, string fileName, CancellationToken ct = default)
     {
diff --git a/src/ClaudeDo.Worker/External/BatchMcpTools.cs b/src/ClaudeDo.Worker/External/BatchMcpTools.cs
index 7fed1f9f..14ccb54e 100644
--- a/src/ClaudeDo.Worker/External/BatchMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/BatchMcpTools.cs
@@ -3,8 +3,14 @@ using ModelContextProtocol.Server;
 
 namespace ClaudeDo.Worker.External;
 
-public sealed record BatchAddTaskInput(string Title, string? Description = null, string? Model = null);
-public sealed record BatchSetMyDayInput(string TaskId, bool IsMyDay, int? SortOrder = null);
+public sealed record BatchAddTaskInput(
+    string Title,
+    [property: Description("Task description/instructions for the agent.")] string? Description = null,
+    [property: Description("Model override: haiku|sonnet|opus. Blank inherits the list/global default.")] string? Model = null);
+public sealed record BatchSetMyDayInput(
+    string TaskId,
+    [property: Description("true to add the task to My Day, false to remove it.")] bool IsMyDay,
+    [property: Description("Position within My Day; omit to append at the end.")] int? SortOrder = null);
 
 // task is populated when found and includeDescription=false (the default, lean reference);
 // taskFull is populated when found and includeDescription=true (full task incl.
@@ -34,14 +40,14 @@ public sealed class BatchMcpTools
     public BatchMcpTools(ExternalMcpService svc) => _svc = svc;
 
     [McpServerTool, Description(
-        "Fetch a snapshot of many tasks in one call (overview / polling a fan-out). " +
-        "Returns one result per id: { id, found, task, taskFull, error }. " +
-        "includeDescription=false (default): found tasks come back in `task` (lean reference, no " +
-        "Description/Result). includeDescription=true: found tasks come back in `taskFull` (incl. " +
-        "Description/Result) instead. A missing id is found=false (not an error; task and taskFull both null); " +
-        "error is only set for an unexpected failure. Max 100 ids.")]
+        "Fetch a snapshot of many tasks in one call — use for an overview or polling a fan-out instead of " +
+        "calling get_task per id. A missing id comes back as found=false, not an error; error is only set " +
+        "for an unexpected failure." + McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchGetTaskResult>> BatchGetTasks(
-        string[] taskIds, bool includeDescription = false, CancellationToken cancellationToken = default)
+        string[] taskIds,
+        [Description("If true, return the full task (incl. Description/Result) in `taskFull`; if false " +
+            "(default), return a lean reference in `task`.")] bool includeDescription = false,
+        CancellationToken cancellationToken = default)
     {
         EnsureWithinCap(taskIds, nameof(taskIds));
 
@@ -75,19 +81,15 @@ public sealed class BatchMcpTools
     }
 
     [McpServerTool, Description(
-        "Create many tasks in one list at once. Each item: { title, description?, model? } " +
-        "(model: haiku|sonnet|opus, blank = inherit list/global default). " +
-        "queueImmediately enqueues every created task. " +
-        "Returns one result per item: { index, title, ok, task, possibleDuplicates, error }; task is " +
-        "a lean reference (id, listId, title, status, sortOrder, isMyDay), not the description you just " +
-        "sent. Each item is always created — possibleDuplicates is a non-blocking heads-up (up to 3 open " +
-        "tasks in the same list with a strongly overlapping title, id/title/status only); check it and " +
-        "mention any hit to the caller, but do not treat it as an error. Max 100 items.")]
+        "Create many tasks in one list at once — use instead of repeated add_task calls when seeding a list. " +
+        "Every item is still created even if it looks like a duplicate; possibleDuplicates is a non-blocking " +
+        "heads-up (up to 3 similar open tasks in the list) worth mentioning to the caller, not an error." +
+        McpToolDocs.LeanTaskRef + McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchAddTaskResult>> BatchAddTasks(
         string listId,
         BatchAddTaskInput[] tasks,
         string? createdBy = null,
-        bool queueImmediately = false,
+        [Description("If true, enqueue every created task immediately instead of leaving it Idle.")] bool queueImmediately = false,
         CancellationToken cancellationToken = default)
     {
         EnsureWithinCap(tasks, nameof(tasks));
@@ -113,11 +115,13 @@ public sealed class BatchMcpTools
     }
 
     [McpServerTool, Description(
-        "Set the status of many tasks at once. status is 'Idle', 'Queued', 'Cancelled' or 'Done' only — " +
-        "same rule as update_task_status ('Done' is refused per-item for a task with an active worktree). " +
-        "Returns one result per id: { taskId, ok, error }. Max 100 ids.")]
+        "Set the status of many tasks at once — use for bulk queue/cancel/done actions instead of calling " +
+        "update_task_status per task. 'Done' is refused per-item for a task with an active worktree." +
+        McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchTaskResult>> BatchUpdateTaskStatus(
-        string[] taskIds, string status, CancellationToken cancellationToken)
+        string[] taskIds,
+        [Description("One of 'Idle', 'Queued', 'Cancelled', or 'Done'.")] string status,
+        CancellationToken cancellationToken)
     {
         EnsureWithinCap(taskIds, nameof(taskIds));
         return await RunPerTaskAsync(taskIds,
@@ -125,9 +129,8 @@ public sealed class BatchMcpTools
     }
 
     [McpServerTool, Description(
-        "Cancel many running tasks at once. Returns one result per id: " +
-        "{ taskId, ok, cancelled, error }. cancelled=false means the task was not running. " +
-        "Max 100 ids.")]
+        "Cancel many running tasks at once — use to bulk-stop tasks instead of calling cancel_task per id. " +
+        "ok=true with cancelled=false just means the task wasn't running." + McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchCancelResult>> BatchCancelTasks(
         string[] taskIds, CancellationToken cancellationToken)
     {
@@ -151,8 +154,8 @@ public sealed class BatchMcpTools
     }
 
     [McpServerTool, Description(
-        "Delete many tasks at once. A Running task is refused (cancel it first) and reported " +
-        "as ok=false with its error. Returns one result per id: { taskId, ok, error }. Max 100 ids.")]
+        "Delete many tasks at once — use for bulk cleanup instead of calling delete_task per id." +
+        McpToolDocs.NotWhileRunning + McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchTaskResult>> BatchDeleteTasks(
         string[] taskIds, CancellationToken cancellationToken)
     {
@@ -162,9 +165,9 @@ public sealed class BatchMcpTools
     }
 
     [McpServerTool, Description(
-        "Daily prep: set/clear MyDay for many tasks at once. Each item: { taskId, isMyDay, sortOrder? }. " +
-        "Still cap-guarded — items that would exceed DailyPrepMaxTasks open MyDay tasks fail individually " +
-        "(ok=false) without blocking the rest. Returns one result per item: { taskId, ok, error }. Max 100 items.")]
+        "Set or clear MyDay (daily prep) for many tasks at once — use instead of calling set_my_day per task. " +
+        "Still cap-guarded: items that would exceed DailyPrepMaxTasks open MyDay tasks fail individually " +
+        "(ok=false) without blocking the rest." + McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchTaskResult>> BatchSetMyDay(
         BatchSetMyDayInput[] items, CancellationToken cancellationToken)
     {
@@ -188,12 +191,13 @@ public sealed class BatchMcpTools
     }
 
     [McpServerTool, Description(
-        "Remove the worktrees of many tasks at once (directory + git branch). " +
-        "force=false refuses a dirty or Running worktree (reported ok=false); force=true removes " +
-        "even a dirty worktree (uncommitted changes lost), still refusing Running tasks. " +
-        "Returns one result per id: { taskId, ok, removed, branchDeleted, error }. Max 100 ids.")]
+        "Remove the worktrees (directory + git branch) of many tasks at once — use for bulk cleanup instead " +
+        "of calling cleanup_task_worktree per id." + McpToolDocs.NotWhileRunning + McpToolDocs.MaxBatch)]
     public async Task<IReadOnlyList<BatchCleanupResult>> BatchCleanupTaskWorktrees(
-        string[] taskIds, bool force = false, CancellationToken cancellationToken = default)
+        string[] taskIds,
+        [Description("If true, also remove a dirty worktree, losing uncommitted changes; a Running task " +
+            "is still refused either way.")] bool force = false,
+        CancellationToken cancellationToken = default)
     {
         EnsureWithinCap(taskIds, nameof(taskIds));
 
diff --git a/src/ClaudeDo.Worker/External/ConfigMcpTools.cs b/src/ClaudeDo.Worker/External/ConfigMcpTools.cs
index 5556d26c..383a13a1 100644
--- a/src/ClaudeDo.Worker/External/ConfigMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/ConfigMcpTools.cs
@@ -46,7 +46,7 @@ public sealed class ConfigMcpTools
         _dbFactory = dbFactory;
     }
 
-    [McpServerTool, Description("Get a list's default config (model, system prompt, agent path). Returns { found: false, config: null } if no config is set.")]
+    [McpServerTool, Description("Read a list's default run config — the fallback used by tasks in this list that don't set their own overrides. Returns { found: false, config: null } if none is set.")]
     public async Task<TaskConfigResult> GetListConfig(string listId, CancellationToken cancellationToken)
     {
         var cfg = await _lists.GetConfigAsync(listId, cancellationToken);
@@ -56,9 +56,8 @@ public sealed class ConfigMcpTools
     }
 
     [McpServerTool, Description(
-        "Set a list's default model/system prompt/agent path/max turns. Passing all four as null clears the list " +
-        "config. Returns { ok, listId, config } — config is null when the config was cleared, otherwise it echoes " +
-        "the fields that were set (a field is null there if it was individually left unset/cleared).")]
+        "Set a list's default model/system prompt/agent path/max turns — the fallback for tasks in this list " +
+        "that don't override them. Passing all four as null clears the list config instead of setting one.")]
     public async Task<SetListConfigResult> SetListConfig(
         string listId, string? model = null, string? systemPrompt = null, string? agentPath = null,
         int? maxTurns = null, CancellationToken cancellationToken = default)
@@ -90,9 +89,8 @@ public sealed class ConfigMcpTools
     }
 
     [McpServerTool, Description(
-        "Set per-task config overrides (model/system prompt/agent path/max turns). Pass null for any field to " +
-        "clear that override. Returns { ok, taskId, config } — config echoes the resulting overrides (a field is " +
-        "null there if it was cleared or never set).")]
+        "Set per-task overrides for model/system prompt/agent path/max turns; these take precedence over the " +
+        "list's default config for this one task. Pass null for any field to clear that override.")]
     public async Task<SetTaskConfigResult> SetTaskConfig(
         string taskId, string? model = null, string? systemPrompt = null, string? agentPath = null,
         int? maxTurns = null, CancellationToken cancellationToken = default)
@@ -109,7 +107,7 @@ public sealed class ConfigMcpTools
         return new SetTaskConfigResult(true, taskId, new TaskConfigDto(m, sp, ap, maxTurns));
     }
 
-    [McpServerTool, Description("Get per-task config overrides (model/system prompt/agent path/max turns). Returns { found: false, config: null } if no override is set on this task.")]
+    [McpServerTool, Description("Read this task's per-task overrides (model/system prompt/agent path/max turns), which take precedence over the list's default config. Returns { found: false, config: null } if none is set.")]
     public async Task<TaskConfigResult> GetTaskConfig(string taskId, CancellationToken cancellationToken)
     {
         var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
@@ -120,11 +118,11 @@ public sealed class ConfigMcpTools
     }
 
     [McpServerTool, Description(
-        "Get the config a task will ACTUALLY run with — model, max turns, effort, permission mode, agent path, " +
-        "whether a system prompt is set, and skill names — with each field's source (task/list/preset/global). " +
-        "Uses the exact same resolution TaskRunner runs with, so this never drifts from get_app_settings/" +
-        "get_task_config's raw, possibly-unused values. maxTurns also reports the raw requested value and " +
-        "whether it was clamped to the global ceiling. Read-only, no side effects.")]
+        "Report the config a task will ACTUALLY run with — model, max turns, effort, permission mode, agent " +
+        "path, whether a system prompt is set, and skill names — each tagged with its source " +
+        "(task/list/preset/global). Use this over get_task_config/get_app_settings when you need resolved " +
+        "values, not raw overrides. maxTurns also reports the raw requested value and whether it was clamped " +
+        "to the global ceiling.")]
     public async Task<EffectiveRunConfigDto> GetEffectiveRunConfig(string taskId, CancellationToken cancellationToken)
     {
         var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
diff --git a/src/ClaudeDo.Worker/External/ExternalMcpService.cs b/src/ClaudeDo.Worker/External/ExternalMcpService.cs
index 00637b00..23fc6319 100644
--- a/src/ClaudeDo.Worker/External/ExternalMcpService.cs
+++ b/src/ClaudeDo.Worker/External/ExternalMcpService.cs
@@ -26,7 +26,6 @@ public sealed record CancelTaskResult(bool Cancelled, string Id);
 // review range (worktree ahead, or HandlerBaseCommit..HandlerHeadCommit for a worktree-less
 // child) contributed nothing, so a reviewer sees them before approving instead of after.
 public sealed record ReviewTaskResult(TaskRefDto Task, string? MergeStatus, IReadOnlyList<string> MergeConflicts, string? MergeMessage, string? RepoPath = null, IReadOnlyList<TaskRefDto>? EmptyChildren = null);
-public sealed record StatusValueDto(string Status, string Meaning);
 public sealed record RunTaskNowResult(bool Started, string TaskId);
 
 public sealed record TaskDto(
@@ -161,7 +160,8 @@ public sealed class ExternalMcpService
         _planningMerge = planningMerge;
     }
 
-    [McpServerTool, Description("List all task lists available in ClaudeDo.")]
+    [McpServerTool, Description(
+        "List all task lists available in ClaudeDo. Start here — every task tool needs a listId from this call.")]
     public async Task<IReadOnlyList<TaskListDto>> ListTaskLists(CancellationToken cancellationToken)
     {
         var lists = await _lists.GetAllAsync(cancellationToken);
@@ -169,17 +169,17 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "List tasks in a given list. Optionally filter by creator (createdBy) and/or status. " +
-        "Valid status values: Idle, Queued, Running, WaitingForReview, WaitingForChildren, Done, Failed, Cancelled. " +
-        "includeDescription=false (default): returns lean task references in `tasks` (no Description/Result) — " +
-        "use this unless you actually need the description text, since a list of verbosely-described tasks can " +
-        "otherwise blow past the response size limit. " +
-        "includeDescription=true: returns full tasks (incl. Description/Result) in `tasksFull` instead; `tasks` is " +
-        "null in that case.")]
+        "List the tasks in one list — the usual way to find a taskId. Optionally filter by creator and/or status.")]
     public async Task<ListTasksResult> ListTasks(
         string listId,
+        [Description("Only return tasks with this CreatedBy value.")]
         string? createdBy = null,
+        [Description("Only return tasks in this status: Idle, Queued, Running, WaitingForReview, " +
+                     "WaitingForChildren, Done, Failed or Cancelled.")]
         string? status = null,
+        [Description("false (default): lean references in `tasks`, no Description/Result — keep this unless you " +
+                     "need the description text, since verbosely-described tasks can blow past the response size " +
+                     "limit. true: full tasks in `tasksFull` instead (`tasks` is then null).")]
         bool includeDescription = false,
         CancellationToken cancellationToken = default)
     {
@@ -206,10 +206,12 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Get a single task by id, including its current status and result. " +
-        "Status lifecycle: Idle → Queued → Running → WaitingForReview → Done | Failed | Cancelled. " +
-        "A successful run lands in WaitingForReview; use review_task to approve, reject, or cancel. " +
-        "Done/Failed/Cancelled tasks can be reset to Idle for re-execution.")]
+        "Get a single task by id, including its current status and result — the canonical reference for what a " +
+        "status means. Lifecycle: Idle → Queued → Running → WaitingForReview → Done | Failed | Cancelled. " +
+        "A successful run lands in WaitingForReview; use review_task to approve, reject or cancel it. " +
+        "Done/Failed/Cancelled tasks can be reset to Idle for re-execution. A Queued task with a blocker waits " +
+        "for its predecessor before the picker will claim it, and WaitingForChildren is a parent whose own work " +
+        "is done but whose children are still running.")]
     public async Task<TaskDto> GetTask(string taskId, CancellationToken cancellationToken)
     {
         var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
@@ -227,21 +229,19 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Create a new task in the given list. Set queueImmediately=true to enqueue it for agent execution. " +
-        "Set model to the cheapest model that can do the task well — 'haiku' for trivial/mechanical work, " +
-        "'sonnet' for normal coding (the default), 'opus' only for complex or cross-cutting work. " +
-        "Leave model null to inherit the list/global default. " +
-        "Returns { task, possibleDuplicates }: task is a lean reference (id, listId, title, status, " +
-        "sortOrder, isMyDay) — not the description you just sent. The task is always created — " +
-        "possibleDuplicates is a non-blocking heads-up (up to 3 open tasks in the same list with a " +
-        "strongly overlapping title, id/title/status only); check it and mention any hit to the caller, " +
-        "but do not treat it as an error.")]
+        "Create a new task in the given list. The task is always created — possibleDuplicates is a non-blocking " +
+        "heads-up (up to 3 open tasks in the same list with a strongly overlapping title); check it and mention " +
+        "any hit to the caller, but do not treat it as an error." + McpToolDocs.LeanTaskRef)]
     public async Task<AddTaskResult> AddTask(
         string listId,
         string title,
         string? description = null,
         string? createdBy = null,
+        [Description("true: enqueue the task for agent execution right away.")]
         bool queueImmediately = false,
+        [Description("Cheapest model that can do the task well: 'haiku' for trivial/mechanical work, 'sonnet' " +
+                     "for normal coding, 'opus' only for complex or cross-cutting work. null inherits the " +
+                     "list/global default (normally sonnet).")]
         string? model = null,
         CancellationToken cancellationToken = default)
     {
@@ -354,9 +354,8 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Update an existing task's title, description, and/or commit type. Pass null to leave a field unchanged. " +
-        "Refuses if the task is currently Running. Returns a lean task reference (id, listId, title, status, " +
-        "sortOrder, isMyDay) — not the description you just sent.")]
+        "Update an existing task's title, description, and/or commit type. Pass null to leave a field unchanged." +
+        McpToolDocs.NotWhileRunning + McpToolDocs.LeanTaskRef)]
     public async Task<TaskRefDto> UpdateTask(
         string taskId,
         string? title = null,
@@ -380,12 +379,12 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Append a subtask (step) to a task. orderNum defaults to the end. " +
-        "Refuses if the task is currently Running. Subtasks are surfaced to the agent at run time and shown in the task's Steps list. " +
-        "Returns a lean task reference (id, listId, title, status, sortOrder, isMyDay), not the task's description.")]
+        "Append a subtask (step) to a task. Subtasks are surfaced to the agent at run time and shown in the " +
+        "task's Steps list." + McpToolDocs.NotWhileRunning + McpToolDocs.LeanTaskRef)]
     public async Task<TaskRefDto> AddSubtask(
         string taskId,
         string title,
+        [Description("Position among the existing steps; defaults to the end.")]
         int? orderNum = null,
         CancellationToken cancellationToken = default)
     {
@@ -419,16 +418,14 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Update a task's status. Only 'Idle', 'Queued', 'Cancelled' and 'Done' are permitted externally — " +
-        "use run_task_now for execution control, and review_task to act on a WaitingForReview task. " +
-        "Settable: Idle (reset to editable), Queued (enqueue for execution), " +
-        "Cancelled (retire the task without deleting it; it can be reset to Idle later), " +
-        "Done (mark complete; refused if the task has an active worktree — use review_task to approve " +
-        "and merge that worktree instead). " +
-        "Full lifecycle: Idle → Queued → Running → WaitingForReview → Done | Failed | Cancelled. " +
-        "Returns a lean task reference (id, listId, title, status, sortOrder, isMyDay), not the task's description.")]
+        "Move a task between the statuses a caller may set directly. Use run_task_now for execution control and " +
+        "review_task to act on a WaitingForReview task — neither is reachable from here." + McpToolDocs.LeanTaskRef)]
     public async Task<TaskRefDto> UpdateTaskStatus(
         string taskId,
+        [Description("'Idle' (reset to editable), 'Queued' (enqueue for execution), 'Cancelled' (retire without " +
+                     "deleting; can be reset to Idle later) or 'Done' (mark complete; refused if the task has an " +
+                     "active worktree — use review_task to approve and merge that worktree instead). No other " +
+                     "value is settable externally.")]
         string status,
         CancellationToken cancellationToken)
     {
@@ -482,27 +479,29 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Review a task that is WaitingForReview. " +
-        "decision='approve' → review+merge, exactly like the UI's Approve: a childless task merges its worktree into " +
-        "targetBranch (default: the repo's current branch) then goes Done; a task with children drives the unit merge " +
-        "(parent worktree if active + each Done child in order); a task without an active worktree approves straight to Done. " +
-        "mergeStatus 'conflict' means the merge stopped on conflicts (files listed) — by default the merge is cleanly " +
-        "aborted and you resolve in the ClaudeDo UI; pass leaveConflictsInTree=true to instead leave the conflict " +
-        "markers in the working tree (repoPath in the result) so you can resolve them and call continue_merge, " +
-        "or abort_merge to cancel. " +
-        "decision='reject_rerun' → Queued and re-runs, resuming the agent's session with your feedback as the next turn (feedback is required). " +
-        "decision='reject_park' → Idle for manual editing (feedback ignored). " +
-        "decision='cancel' → Cancelled. " +
-        "Fails if the task is not currently WaitingForReview (except cancel, which also works while Running/Queued). " +
-        "The result's task field is a lean reference (id, listId, title, status, sortOrder, isMyDay), not the task's description. " +
-        "emptyChildren (parent approve only) lists the Done children about to be unit-merged whose own review range " +
-        "contributed nothing (e.g. a child that reported CLAUDEDO_BLOCKED and committed no code) — check it before " +
-        "trusting that every child actually delivered something.")]
+        "Act on a task that is WaitingForReview — the only way to approve, reject or retire a reviewed run. " +
+        "'approve' is review+merge, exactly like the UI's Approve: a childless task merges its worktree into " +
+        "targetBranch then goes Done; a task with children drives the unit merge (parent worktree if active + each " +
+        "Done child in order); a task without an active worktree approves straight to Done. Fails if the task is " +
+        "not WaitingForReview (except 'cancel', which also works while Running/Queued). mergeStatus 'conflict' " +
+        "means the merge stopped on conflicts, with the files listed. emptyChildren (parent approve only) lists " +
+        "the Done children about to be unit-merged whose own review range contributed nothing (e.g. a child that " +
+        "reported CLAUDEDO_BLOCKED and committed no code) — check it before trusting that every child actually " +
+        "delivered something." + McpToolDocs.LeanTaskRef)]
     public async Task<ReviewTaskResult> ReviewTask(
         string taskId,
+        [Description("'approve', 'reject_rerun', 'reject_park' or 'cancel'.")]
         string decision,
+        [Description("Rejection comment. Required for 'reject_rerun', where the task goes Queued and re-runs with " +
+                     "this text as the next turn of the agent's resumed session; ignored for 'reject_park', which " +
+                     "just returns the task to Idle for manual editing.")]
         string? feedback = null,
+        [Description("Branch an approve merges into; defaults to the repo's current branch.")]
         string? targetBranch = null,
+        [Description("What an approve does when the merge hits conflicts. false (default): abort cleanly, leaving " +
+                     "no half-merged state, and you resolve in the ClaudeDo UI. true: leave the conflict markers " +
+                     "in the working tree (repoPath in the result) so you can resolve them and call continue_merge, " +
+                     "or abort_merge to cancel.")]
         bool leaveConflictsInTree = false,
         CancellationToken cancellationToken = default)
     {
@@ -634,7 +633,10 @@ public sealed class ExternalMcpService
         }
     }
 
-    [McpServerTool, Description("Immediately run a task in the override execution slot (bypasses the agent queue). Returns { started: true, taskId } on success.")]
+    [McpServerTool, Description(
+        "Run a task immediately in the override execution slot, bypassing the agent queue. That slot is single-" +
+        "occupancy and shared with continue_task — throws \"Override slot busy\" if something else holds it; " +
+        "enqueue via update_task_status instead of retrying in a loop.")]
     public async Task<RunTaskNowResult> RunTaskNow(string taskId, CancellationToken cancellationToken)
     {
         try
@@ -653,7 +655,8 @@ public sealed class ExternalMcpService
         return new RunTaskNowResult(true, taskId);
     }
 
-    [McpServerTool, Description("Cancel a running task. Returns { cancelled: true, id } if the task was running and cancellation was requested; cancelled is false if the task was not running.")]
+    [McpServerTool, Description(
+        "Cancel a running task, killing its agent process. cancelled=false means the task was not running.")]
     public async Task<CancelTaskResult> CancelTask(string taskId, CancellationToken cancellationToken)
     {
         var cancelled = _queue.CancelTask(taskId);
@@ -661,7 +664,9 @@ public sealed class ExternalMcpService
         return new CancelTaskResult(cancelled, taskId);
     }
 
-    [McpServerTool, Description("Delete a task. Returns { deleted: true, id } on success. Throws if the task is not found or is currently Running — cancel it first.")]
+    [McpServerTool, Description(
+        "Delete a task permanently. Prefer update_task_status 'Cancelled' to retire a task you may want back." +
+        McpToolDocs.NotWhileRunning)]
     public async Task<DeleteTaskResult> DeleteTask(string taskId, CancellationToken cancellationToken)
     {
         var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
@@ -676,31 +681,12 @@ public sealed class ExternalMcpService
         return new DeleteTaskResult(true, taskId);
     }
 
-    // ── Status reference ─────────────────────────────────────────────────────
-
-    [McpServerTool, Description("Returns all valid task status values and their meanings. Use before filtering by status or interpreting task state.")]
-    public Task<IReadOnlyList<StatusValueDto>> GetTaskStatusValues() =>
-        Task.FromResult<IReadOnlyList<StatusValueDto>>([
-            new("Idle",                "Not yet queued; task is editable and will not run until enqueued."),
-            new("Queued",              "Waiting for an agent execution slot. Tasks with a blocker (BlockedByTaskId) are skipped by the queue picker until their predecessor finishes."),
-            new("Running",             "Agent is actively executing the task; cannot be edited or deleted until cancelled."),
-            new("WaitingForReview",    "Run finished successfully and awaits review. Use review_task: approve (→ Done), reject_rerun (→ Queued, resumes the session with feedback), reject_park (→ Idle), or cancel (→ Cancelled)."),
-            new("WaitingForChildren",  "Planning parent whose child tasks are still running. The parent resumes once all children reach a terminal state."),
-            new("Done",                "Completed successfully and approved; result text is available in the result field. Can be reset to Idle for re-execution."),
-            new("Failed",              "Execution ended with an error; task can be reset to Idle or re-queued directly."),
-            new("Cancelled",           "Cancelled by the user; task can be reset to Idle or re-queued directly."),
-        ]);
-
     // ── Worktree / git tools ──────────────────────────────────────────────────
 
     [McpServerTool, Description(
-        "Get git worktree details for a task: path, branch, headCommit (current HEAD SHA), " +
-        "baseCommit (SHA where the branch was created), ahead (commits on branch since base), " +
-        "behind (commits on main not yet on this branch; 0 if 'main' ref is unreachable), " +
-        "isDirty (has uncommitted changes in the worktree directory), " +
-        "mergeCommit (SHA of the merge commit this worktree's branch produced on the target branch, " +
-        "if it has been merged and that succeeded after this field was introduced; null otherwise — " +
-        "required by revert_merge). " +
+        "Get a task's git worktree state — path, branch, base/head commit, ahead/behind counts, isDirty, and the " +
+        "mergeCommit its branch produced once merged. behind is 0 when the 'main' ref is unreachable, so do not " +
+        "read 0 as \"up to date\" without checking. A null mergeCommit means revert_merge cannot act on this task. " +
         "Throws if the task or its worktree does not exist.")]
     public async Task<WorktreeInfoDto> GetTaskWorktree(string taskId, CancellationToken cancellationToken)
     {
@@ -718,16 +704,17 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Get the diff for a task's worktree relative to its base commit. For a worktree-less " +
-        "list-handler host task (Mission Control's \"Let Claude handle it\"), returns the fixed " +
-        "HandlerBaseCommit..HandlerHeadCommit range over the list's working dir instead. " +
-        "stat=false (default): returns the full unified diff, capped at 200 KB (truncated=true when larger). " +
-        "stat=true: returns a --stat summary (changed files with insertion/deletion counts). " +
-        "files always lists the changed file paths regardless of stat mode. " +
-        "totalBytes is the uncapped diff size (useful when truncated=true). " +
-        "Throws if the task has no worktree/review range, or the relevant directory is missing from disk.")]
+        "Read what a task actually changed — the diff of its worktree against its base commit (for a worktree-less " +
+        "list-handler host task, the fixed HandlerBaseCommit..HandlerHeadCommit range over the list's working dir " +
+        "instead). files lists the changed paths in either mode; truncated=true means the diff was capped and " +
+        "totalBytes holds its real size. Throws if the task has no worktree/review range, or the relevant " +
+        "directory is missing from disk.")]
     public async Task<TaskDiffDto> GetTaskDiff(
-        string taskId, bool stat = false, CancellationToken cancellationToken = default)
+        string taskId,
+        [Description("false (default): the full unified diff, capped at 200 KB. true: a --stat summary with " +
+                     "per-file insertion/deletion counts — start here when the diff may be large.")]
+        bool stat = false,
+        CancellationToken cancellationToken = default)
     {
         var (repoPath, baseCommit, headCommit) = await LoadDiffRangeAsync(taskId, cancellationToken);
 
@@ -782,21 +769,21 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Merge a task's worktree branch into targetBranch (default: main). " +
-        "noFf=true (default): always creates a merge commit (--no-ff). " +
-        "dryRun=true: validates preconditions only, does not perform the merge; merged=false in the result means 'not actually merged'. " +
-        "allowWaitingForReview=true: also allows merging a task in WaitingForReview (default false, which only allows Done). " +
-        "On success: merged=true, mergeCommit contains the new merge commit SHA. " +
-        "On conflict: by default the merge is cleanly aborted (no half-merged state left); merged=false and conflicts lists the affected files. " +
-        "leaveConflictsInTree=true: on conflict the merge is NOT aborted — conflict markers are left in the working " +
-        "tree at repoPath (conflictsInTree=true in the result) so you can resolve them there and call continue_merge, " +
-        "or abort_merge to cancel.")]
+        "Merge a Done task's worktree branch into targetBranch. For a task still in WaitingForReview prefer " +
+        "review_task, which merges as part of approving. merged=true carries the new mergeCommit SHA; on conflict " +
+        "merged=false and conflicts lists the affected files.")]
     public async Task<MergeTaskResultDto> MergeTask(
         string taskId,
         string targetBranch = "main",
+        [Description("true (default): always create a merge commit (--no-ff).")]
         bool noFf = true,
+        [Description("true: validate preconditions only and do not merge — merged=false then means \"not attempted\".")]
         bool dryRun = false,
+        [Description("true: also allow merging a task in WaitingForReview; false (default) allows Done only.")]
         bool allowWaitingForReview = false,
+        [Description("What to do on conflict. false (default): abort cleanly, leaving no half-merged state. true: " +
+                     "leave the conflict markers in the working tree at repoPath (conflictsInTree=true) so you can " +
+                     "resolve them there and call continue_merge, or abort_merge to cancel.")]
         bool leaveConflictsInTree = false,
         CancellationToken cancellationToken = default)
     {
@@ -848,11 +835,9 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Finish an in-progress conflicted merge after the conflict markers in the working tree (repoPath from " +
-        "merge_task/review_task) have been resolved. Handles both a single task's merge and a parent/children unit " +
-        "merge — pass the PARENT task id to continue a unit merge. On success merged=true and the task reaches its " +
-        "post-merge status (Done when approving). If conflict markers are still present, merged=false and conflicts " +
-        "lists the affected files — resolve them and call continue_merge again. " +
+        "Finish an in-progress conflicted merge once you have resolved the conflict markers in the working tree " +
+        "(repoPath from merge_task/review_task). Pass the PARENT task id to continue a parent/children unit merge. " +
+        "merged=false with conflicts listed means markers are still present — resolve them and call again. " +
         "Throws if there is no in-progress merge for the task; use abort_merge to cancel a paused merge instead.")]
     public async Task<MergeContinuationResultDto> ContinueMerge(string taskId, CancellationToken cancellationToken)
     {
@@ -920,10 +905,8 @@ public sealed class ExternalMcpService
 
     [McpServerTool, Description(
         "Abort an in-progress conflicted merge, discarding the conflict markers and restoring a clean working tree. " +
-        "Handles both a single task's merge and a parent/children unit merge — pass the PARENT task id to abort a " +
-        "unit merge. The task keeps its pre-merge status (e.g. WaitingForReview). " +
-        "Throws if there is no in-progress merge for the task. " +
-        "Returns a lean task reference (id, listId, title, status, sortOrder, isMyDay), not the task's description.")]
+        "Pass the PARENT task id to abort a parent/children unit merge. The task keeps its pre-merge status " +
+        "(e.g. WaitingForReview). Throws if there is no in-progress merge for the task." + McpToolDocs.LeanTaskRef)]
     public async Task<TaskRefDto> AbortMerge(string taskId, CancellationToken cancellationToken)
     {
         _ = await _tasks.GetByIdAsync(taskId, cancellationToken)
@@ -945,21 +928,17 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Non-destructive merge preview for a task's worktree branch against targetBranch (default: the repo's " +
-        "current branch), via `git merge-tree --write-tree` — does NOT touch the working tree, index, or HEAD. " +
-        "status: 'clean' (mergeable; changedFileCount is the size of that merge) or 'conflict' (conflictFiles " +
-        "lists the paths git would stop on). behind = commits on targetBranch not yet on this task's branch, so " +
-        "you can spot a stale branch even when the preview itself is clean. " +
-        "IMPORTANT: a clean preview says nothing about whether the merged result compiles or passes tests — git " +
-        "can merge two changes cleanly (e.g. one file deletes a symbol another file still references) and still " +
-        "break the build. " +
-        "isEmpty=true means the task's review range contributed nothing (no commits ahead of base, or — for a " +
-        "worktree-less list-handler host task — HandlerBaseCommit == HandlerHeadCommit); do not mistake a small " +
-        "changedFileCount for an empty one, check isEmpty instead. " +
-        "Throws a clear error if the task has neither an active worktree nor a handler commit range, or the " +
-        "list's working directory is missing from disk.")]
+        "Check whether a task would merge cleanly before touching anything — `git merge-tree --write-tree`, so the " +
+        "working tree, index and HEAD are untouched. status is 'clean' or 'conflict' (conflictFiles lists where git " +
+        "would stop); behind counts commits on targetBranch not yet on this branch, which flags a stale branch even " +
+        "when the preview is clean. IMPORTANT: a clean preview says nothing about whether the result compiles or " +
+        "passes tests — git can merge two changes cleanly (one file deleting a symbol another still references) and " +
+        "still break the build. isEmpty=true means the task's review range contributed nothing; check that flag " +
+        "rather than reading a small changedFileCount as empty. Throws if the task has neither an active worktree " +
+        "nor a handler commit range, or the list's working directory is missing from disk.")]
     public async Task<MergePreviewToolDto> PreviewMerge(
         string taskId,
+        [Description("Branch to preview against; defaults to the repo's current branch.")]
         string? targetBranch = null,
         CancellationToken cancellationToken = default)
     {
@@ -968,18 +947,16 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Merge preview plus file-overlap check across several tasks at once, all previewed against the same " +
-        "targetBranch (default: the repo's current branch). For each taskId returns the same fields as " +
-        "preview_merge (status/conflictFiles/changedFileCount/behind; error is set instead if that task could not " +
-        "be previewed, and it is then excluded from the overlap computation). overlaps lists, for each file " +
-        "touched by MORE THAN ONE of the given tasks (via each task's own diff, not the merge preview itself), " +
-        "which tasks touch it — passing a single taskId always yields an empty overlaps list. " +
-        "IMPORTANT: file-name overlap is a HINT, not a guarantee of a real collision, and its absence is not a " +
-        "guarantee of safety — two tasks touching different files entirely (e.g. one deletes a symbol, another " +
-        "still references it elsewhere) can still collide, and this tool will not flag that case. " +
-        "isEmpty=true (per entry) means that task's review range contributed nothing — see preview_merge.")]
+        "Plan a batch merge: preview_merge for several tasks against the same targetBranch, plus a file-overlap " +
+        "check between them. Per entry you get preview_merge's fields, or error instead when that task could not " +
+        "be previewed (it is then left out of the overlap computation). overlaps names, for each file touched by " +
+        "MORE THAN ONE of the given tasks, which tasks touch it — a single taskId always yields no overlaps. " +
+        "IMPORTANT: overlap is a HINT and its absence is not safety — two tasks touching entirely different files " +
+        "(one deleting a symbol, another still referencing it) can still collide unflagged, and as with " +
+        "preview_merge a clean result does not mean the merge builds.")]
     public async Task<MergePreviewSetResultDto> PreviewMergeSet(
         IReadOnlyList<string> taskIds,
+        [Description("Branch to preview every task against; defaults to the repo's current branch.")]
         string? targetBranch = null,
         CancellationToken cancellationToken = default)
     {
@@ -1076,18 +1053,17 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Revert a previously merged task's merge commit on targetBranch (default: main), via `git revert -m 1` — " +
-        "a new commit, never a reset/rewrite (the target working directory is shared with other sessions). " +
-        "Requires the task to be Done with a Merged worktree that has a recorded merge commit; tasks merged " +
-        "before this feature existed have no recorded commit and are refused rather than guessed via git log. " +
-        "On success: reverted=true, revertCommit is the new commit's SHA, and the task returns to " +
-        "WaitingForReview so it can be reconsidered. " +
-        "On a conflicting revert: reverted=false, the revert is aborted immediately (no half-resolved state " +
-        "left in the tree) and conflicts lists the files that would have conflicted. " +
-        "Throws if there is no recorded merge commit, the repo is mid-merge/mid-revert, or the target working " +
-        "tree has uncommitted changes from another session.")]
+        "Undo a merged task by reverting its merge commit — `git revert -m 1`, always a new commit and never a " +
+        "reset/rewrite, since the target working directory is shared with other sessions. Requires the task to be " +
+        "Done with a Merged worktree that has a recorded merge commit (check get_task_worktree's mergeCommit " +
+        "first). On success the task returns to WaitingForReview so it can be reconsidered. On conflict the revert " +
+        "is aborted immediately and conflicts lists the files. Throws if there is no recorded merge commit, the " +
+        "repo is mid-merge/mid-revert, or the target working tree has uncommitted changes from another session.")]
     public async Task<RevertMergeResultDto> RevertMerge(
-        string taskId, string targetBranch = "main", CancellationToken cancellationToken = default)
+        string taskId,
+        [Description("Branch carrying the merge commit; defaults to main.")]
+        string targetBranch = "main",
+        CancellationToken cancellationToken = default)
     {
         var result = await _merge.RevertMergeAsync(taskId, targetBranch, cancellationToken);
 
@@ -1104,10 +1080,8 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "List all ClaudeDo-tracked worktrees. " +
-        "Each entry: taskId, path, branch, headCommit (empty if path missing on disk), " +
-        "isDirty (has uncommitted changes), mergedIntoMain (worktree state is Merged). " +
-        "Only worktrees recorded in the ClaudeDo database are returned.")]
+        "Survey every worktree ClaudeDo tracks — use it to find leftovers to clean up. Only worktrees recorded in " +
+        "the ClaudeDo database appear here, and headCommit is empty when the path is missing from disk.")]
     public async Task<IReadOnlyList<WorktreeListItemDto>> ListWorktrees(CancellationToken cancellationToken)
     {
         var rows = await _maintenance.GetOverviewAsync(null, cancellationToken);
@@ -1125,12 +1099,14 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Remove a task's worktree directory and delete its git branch. " +
-        "force=false (default): refuses if the worktree has uncommitted changes or the task is Running. " +
-        "force=true: removes even a dirty worktree (uncommitted changes are lost); task must not be Running. " +
-        "Returns removed=true on success; branchDeleted reflects whether the branch was also removed.")]
+        "Remove a task's worktree directory and delete its git branch. branchDeleted reports whether the branch " +
+        "went too." + McpToolDocs.NotWhileRunning)]
     public async Task<CleanupWorktreeResult> CleanupTaskWorktree(
-        string taskId, bool force = false, CancellationToken cancellationToken = default)
+        string taskId,
+        [Description("false (default): refuse a worktree with uncommitted changes. true: remove it anyway, losing " +
+                     "those changes.")]
+        bool force = false,
+        CancellationToken cancellationToken = default)
     {
         using var ctx = _dbFactory.CreateDbContext();
         var task = await new TaskRepository(ctx).GetByIdAsync(taskId, cancellationToken)
@@ -1155,10 +1131,9 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Send a follow-up prompt to an existing Claude session (multi-turn continuation). " +
-        "The agent resumes using --resume with the session ID from the task's last run. " +
-        "Runs in the override execution slot; throws if the slot is busy — try again later. " +
-        "Returns a status string from the execution slot.")]
+        "Send a follow-up prompt to a task's existing Claude session instead of starting a fresh run — the agent " +
+        "resumes via --resume with the session id from the task's last run, so its prior context is kept. Uses the " +
+        "same single-occupancy override slot as run_task_now and throws \"Override slot busy\" when that is taken.")]
     public async Task<string> ContinueTask(
         string taskId,
         string followUpPrompt,
@@ -1187,10 +1162,10 @@ public sealed class ExternalMcpService
     // ── Daily prep ───────────────────────────────────────────────────────────
 
     [McpServerTool, Description(
-        "Daily prep: returns the open tasks eligible for today's MyDay selection. " +
-        "candidates = Idle, not blocked, in a git repo not excluded from the weekly report, and not already in MyDay. " +
-        "currentMyDay = Idle tasks already flagged IsMyDay (count them toward the cap). " +
-        "maxTasks = the hard cap on total open MyDay tasks. Use set_my_day to add tasks (never exceed maxTasks).")]
+        "Daily prep: the open tasks eligible for today's MyDay selection. candidates are Idle, unblocked, " +
+        "non-manual and in a git repo not excluded from the weekly report; currentMyDay are Idle tasks already " +
+        "flagged and count toward maxTasks, the hard cap on open MyDay tasks. Add your picks with set_my_day and " +
+        "never exceed maxTasks.")]
     public async Task<DailyPrepDataDto> GetDailyPrepCandidates(CancellationToken cancellationToken)
     {
         await using var ctx = await _dbFactory.CreateDbContextAsync(cancellationToken);
@@ -1225,14 +1200,13 @@ public sealed class ExternalMcpService
     }
 
     [McpServerTool, Description(
-        "Daily prep: set or clear a task's MyDay flag, optionally setting its sortOrder " +
-        "(use consecutive sortOrder values to keep related tasks together). " +
-        "Setting isMyDay=true is rejected if it would exceed the MyDay cap (DailyPrepMaxTasks open MyDay tasks); " +
-        "clearing (isMyDay=false) is always allowed. " +
-        "Returns a lean task reference (id, listId, title, status, sortOrder, isMyDay), not the task's description.")]
+        "Daily prep: set or clear a task's MyDay flag. Setting it is rejected once the MyDay cap " +
+        "(DailyPrepMaxTasks open MyDay tasks) would be exceeded; clearing is always allowed." +
+        McpToolDocs.LeanTaskRef)]
     public async Task<TaskRefDto> SetMyDay(
         string taskId,
         bool isMyDay,
+        [Description("Position in the MyDay list; use consecutive values to keep related tasks together.")]
         int? sortOrder = null,
         CancellationToken cancellationToken = default)
     {
diff --git a/src/ClaudeDo.Worker/External/HandoffMcpTools.cs b/src/ClaudeDo.Worker/External/HandoffMcpTools.cs
index 6866d7c4..b44d05b7 100644
--- a/src/ClaudeDo.Worker/External/HandoffMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/HandoffMcpTools.cs
@@ -20,13 +20,15 @@ public sealed class HandoffMcpTools
     }
 
     [McpServerTool, Description(
-        "End of Phase 2 for the list handler (\"Let Claude handle it\"): hand this run off to a fresh " +
-        "ConPTY session that carries out Phases 3-5, without dragging along this session's dedupe/rewrite " +
-        "context. taskId is this session's own handler task id; survivingTaskIds are the tasks that made " +
-        "it past dedupe, in the order to run them. Reuses the SAME handler task -- no new task is created, " +
-        "and HandlerBaseCommit is untouched. The current tile stays open; end your own turn after calling this.")]
+        "Call at the end of Phase 2 of the list handler (\"Let Claude handle it\") to hand this run off " +
+        "to a fresh ConPTY session that carries out Phases 3-5, without dragging along this session's " +
+        "dedupe/rewrite context. Reuses the SAME handler task -- no new task is created, and " +
+        "HandlerBaseCommit is untouched. The current tile stays open; you must end your own turn " +
+        "immediately after calling this.")]
     public async Task<HandoffListHandlerResult> HandoffListHandler(
-        string taskId, IReadOnlyList<string> survivingTaskIds, CancellationToken cancellationToken)
+        [Description("This session's own handler task id.")] string taskId,
+        [Description("The tasks that made it past dedupe, in the order to run them.")] IReadOnlyList<string> survivingTaskIds,
+        CancellationToken cancellationToken)
     {
         if (survivingTaskIds.Count == 0)
             throw new InvalidOperationException("survivingTaskIds must contain at least one task id.");
diff --git a/src/ClaudeDo.Worker/External/LifecycleMcpTools.cs b/src/ClaudeDo.Worker/External/LifecycleMcpTools.cs
index aa1ecb7a..3980f51f 100644
--- a/src/ClaudeDo.Worker/External/LifecycleMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/LifecycleMcpTools.cs
@@ -20,7 +20,7 @@ public sealed class LifecycleMcpTools
         _reset = reset;
     }
 
-    [McpServerTool, Description("Reset a failed task: discards its worktree and returns it to Idle so it can be run again. Only Failed tasks are accepted. Returns { reset: true, taskId } on success.")]
+    [McpServerTool, Description("Reset a failed task back to Idle so it can be run again, discarding its now-stale worktree. Only tasks with Status=Failed are accepted; other statuses throw.")]
     public async Task<ResetFailedTaskResult> ResetFailedTask(string taskId, CancellationToken cancellationToken)
     {
         var task = await _tasks.GetByIdAsync(taskId, cancellationToken)
diff --git a/src/ClaudeDo.Worker/External/ListMcpTools.cs b/src/ClaudeDo.Worker/External/ListMcpTools.cs
index 72fe5f2f..5ac26da7 100644
--- a/src/ClaudeDo.Worker/External/ListMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/ListMcpTools.cs
@@ -21,9 +21,14 @@ public sealed class ListMcpTools
         _broadcaster = broadcaster;
     }
 
-    [McpServerTool, Description("Create a new task list. workingDir sets the git repo tasks run against; commitType defaults to 'chore'.")]
+    [McpServerTool, Description("Create a new task list — the top-level grouping tasks belong to, with its own working dir, commit type, and default run config.")]
     public async Task<ListSummaryDto> CreateList(
-        string name, string? workingDir = null, string? commitType = null, CancellationToken cancellationToken = default)
+        string name,
+        [Description("Absolute local path to an existing git repository this list's tasks will run against. Not validated here — the first task run fails if the path isn't an actual git repo. Omit to run this list's tasks in a throwaway sandbox with no worktree.")]
+        string? workingDir = null,
+        [Description("Conventional-commit-style type prefix for this list's task commits (e.g. 'feat', 'fix'). Defaults to 'chore'.")]
+        string? commitType = null,
+        CancellationToken cancellationToken = default)
     {
         if (string.IsNullOrWhiteSpace(name))
             throw new InvalidOperationException("name is required.");
@@ -41,9 +46,14 @@ public sealed class ListMcpTools
         return ToDto(entity);
     }
 
-    [McpServerTool, Description("Rename a list and/or change its working dir and default commit type. Pass null to leave a field unchanged.")]
+    [McpServerTool, Description("Rename a list, or change its working dir / default commit type without recreating it. Pass null for any field to leave it unchanged.")]
     public async Task<ListSummaryDto> UpdateList(
-        string listId, string? name = null, string? workingDir = null, string? commitType = null,
+        string listId,
+        string? name = null,
+        [Description("Absolute local path to an existing git repository this list's tasks will run against; not validated until the next task runs. Null leaves it unchanged; pass an empty string to clear it and switch this list to sandbox-only task runs.")]
+        string? workingDir = null,
+        [Description("New default commit type prefix for this list's task commits. Null leaves it unchanged.")]
+        string? commitType = null,
         CancellationToken cancellationToken = default)
     {
         var entity = await _lists.GetByIdAsync(listId, cancellationToken)
@@ -62,7 +72,7 @@ public sealed class ListMcpTools
         return ToDto(entity);
     }
 
-    [McpServerTool, Description("Delete a list and its tasks. Irreversible. Returns { deleted: true, id } on success.")]
+    [McpServerTool, Description("Permanently delete a list and all its tasks — no undo. Only for removing the whole list, not a single task within it.")]
     public async Task<DeleteListResult> DeleteList(string listId, CancellationToken cancellationToken)
     {
         _ = await _lists.GetByIdAsync(listId, cancellationToken)
diff --git a/src/ClaudeDo.Worker/External/McpToolDocs.cs b/src/ClaudeDo.Worker/External/McpToolDocs.cs
new file mode 100644
index 00000000..46b814af
--- /dev/null
+++ b/src/ClaudeDo.Worker/External/McpToolDocs.cs
@@ -0,0 +1,28 @@
+namespace ClaudeDo.Worker.External;
+
+/// <summary>
+/// Boilerplate clauses shared by several external MCP tool descriptions. Every tool description is
+/// still emitted in full to the client — these constants only stop the wording from drifting apart
+/// across ~50 attributes.
+///
+/// Description style (keep new tools in line with it):
+///  1. First sentence says what the tool does AND when to reach for it — MCP clients rank tools by
+///     this text, so the trigger must not be buried behind return-shape prose.
+///  2. Then only non-obvious preconditions and refusals.
+///  3. Document parameters with [Description] on the parameter, not in the tool description.
+///  4. Describe result fields only where the caller must branch on them (isEmpty, truncated,
+///     conflicts, …). Everything else is visible in the first actual response.
+///  5. No design rationale or "since this feature was introduced" history.
+///  Budget: ~400 chars for a simple tool, ~800 for the merge/review family.
+/// </summary>
+internal static class McpToolDocs
+{
+    /// <summary>Warns that the payload is the lean reference, not the task's description/result.</summary>
+    public const string LeanTaskRef = " Returns a lean task reference, not the task's description.";
+
+    /// <summary>Batch-size cap shared by every BatchMcpTools entry point.</summary>
+    public const string MaxBatch = " Max 100 per call.";
+
+    /// <summary>Mutations that refuse to touch a task while its agent is running.</summary>
+    public const string NotWhileRunning = " Refused while the task is Running — cancel it first.";
+}
diff --git a/src/ClaudeDo.Worker/External/QueueStateMcpTools.cs b/src/ClaudeDo.Worker/External/QueueStateMcpTools.cs
index fc1e9763..d1d65ca4 100644
--- a/src/ClaudeDo.Worker/External/QueueStateMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/QueueStateMcpTools.cs
@@ -28,15 +28,12 @@ public sealed class QueueStateMcpTools
     }
 
     [McpServerTool, Description(
-        "Read-only snapshot of the execution queue -- observe slot occupancy instead of inferring " +
-        "it from maxParallelExecutions. Result: { configuredSlots, effectiveSlots, activeSlots: " +
-        "[{ slot, taskId, startedAt }], waitingTaskIds }. configuredSlots is Settings -> " +
-        "MaxParallelExecutions; effectiveSlots is that value stepped down by the usage throttle " +
-        "(lower when the 5h/7d usage window is filling up) -- compare the two to see whether " +
-        "throttling is currently active. activeSlots lists every task presently holding an " +
-        "execution slot, with slot \"queue\" for a normal queue slot or \"override\" for the single " +
-        "run_task_now/continue_task slot. waitingTaskIds lists queued, unblocked, non-manual, due " +
-        "tasks in the order the queue would pick them next.")]
+        "Read-only snapshot of the execution queue -- call this to observe slot occupancy instead " +
+        "of inferring it from maxParallelExecutions. effectiveSlots is configuredSlots stepped down " +
+        "by the usage throttle (lower when the 5h/7d usage window fills up), so comparing the two " +
+        "shows whether throttling is currently active. Each active slot is \"queue\" (a normal " +
+        "queue slot) or \"override\" (the single run_task_now/continue_task slot). waitingTaskIds " +
+        "lists queued, unblocked, non-manual, due tasks in the order the queue would pick them next.")]
     public async Task<GetQueueStateResult> GetQueueState(CancellationToken cancellationToken = default)
     {
         var (configured, effective) = await _queue.GetSlotCountsAsync(cancellationToken);
diff --git a/src/ClaudeDo.Worker/External/RunHistoryMcpTools.cs b/src/ClaudeDo.Worker/External/RunHistoryMcpTools.cs
index 06e4d799..d334fc7a 100644
--- a/src/ClaudeDo.Worker/External/RunHistoryMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/RunHistoryMcpTools.cs
@@ -24,14 +24,17 @@ public sealed class RunHistoryMcpTools
 
     public RunHistoryMcpTools(TaskRunRepository runs) => _runs = runs;
 
-    [McpServerTool, Description("List all execution runs for a task (newest run metadata, tokens, turns, result, error).")]
+    [McpServerTool, Description(
+        "List all execution runs for a task — metadata, tokens, turns, result, and error per run — ordered " +
+        "oldest to newest by run number, so the last entry is the most recent. Use a run's id from here with " +
+        "get_run to fetch it individually.")]
     public async Task<IReadOnlyList<RunDto>> ListRuns(string taskId, CancellationToken cancellationToken)
     {
         var runs = await _runs.GetByTaskIdAsync(taskId, cancellationToken);
         return runs.Select(ToDto).ToList();
     }
 
-    [McpServerTool, Description("Get a single execution run by its run id.")]
+    [McpServerTool, Description("Get one execution run's full detail by its run id, obtained from list_runs.")]
     public async Task<RunDto> GetRun(string runId, CancellationToken cancellationToken)
     {
         var run = await _runs.GetByIdAsync(runId, cancellationToken)
@@ -40,18 +43,16 @@ public sealed class RunHistoryMcpTools
     }
 
     [McpServerTool, Description(
-        "Fetch log entries from a task's latest run. " +
-        "Returns { available, entries, totalLines, truncated }. " +
-        "available=false means no log exists yet (task is queued or just started — not an error). " +
-        "entries are the individual lines (NDJSON messages) from Claude's streaming output. " +
-        "Default: returns the last 50 entries (tail=50). " +
-        "tail: override the number of trailing entries to return. " +
-        "offset+limit: return entries starting at position offset (0-based); overrides tail when provided. " +
-        "truncated=true when fewer entries are returned than totalLines.")]
+        "Fetch NDJSON log lines from a task's latest run — use this to check progress or debug a task without " +
+        "opening the log file. Defaults to the last 50 lines. available=false means no log exists yet (queued " +
+        "or just started — not an error); truncated=true when fewer entries are returned than totalLines.")]
     public async Task<TaskLogResult> GetTaskLog(
         string taskId,
+        [Description("Number of trailing entries to return; ignored if offset or limit is set. Default 50.")]
         int? tail = null,
+        [Description("0-based entry index to start from; overrides tail when set. Combine with limit to page through the log.")]
         int? offset = null,
+        [Description("Max entries to return starting at offset. Omit to return everything from offset to the end.")]
         int? limit = null,
         CancellationToken cancellationToken = default)
     {
diff --git a/src/ClaudeDo.Worker/External/TaskWaitMcpTools.cs b/src/ClaudeDo.Worker/External/TaskWaitMcpTools.cs
index cede7a45..850a05fb 100644
--- a/src/ClaudeDo.Worker/External/TaskWaitMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/TaskWaitMcpTools.cs
@@ -29,19 +29,24 @@ public sealed class TaskWaitMcpTools
     }
 
     [McpServerTool, Description(
-        "Blocks until at least one of the given tasks leaves Queued/Running, or until timeoutSeconds elapses " +
-        "(clamped server-side to 900s). Returns immediately if any task is already outside Queued/Running " +
-        "when called (an unknown id is reported as status \"NotFound\" and counts as changed). Use this instead " +
-        "of polling get_task in a loop. Pitfall: a planning parent with children goes Running -> " +
-        "WaitingForChildren while its children are still working, and by default that counts as \"changed\" -- " +
-        "so waiting on a parent returns immediately even though the work isn't done. Set " +
-        "treatWaitingForChildrenAsBusy=true to keep waiting through WaitingForChildren; the call then only " +
-        "returns once the parent reaches WaitingForReview or a terminal status (default: false, unchanged " +
-        "legacy behavior). Requires the calling claude process to run with MCP_TOOL_TIMEOUT >= 930000 (ms) for " +
-        "a long wait to actually be held open -- ClaudeDo's own launchers already set this. " +
-        "Result: { changed: [{ taskId, status }], timedOut }.")]
+        "Blocks until at least one of the given tasks leaves Queued/Running -- use this instead of " +
+        "polling get_task in a loop. Returns immediately if a task is already outside Queued/Running " +
+        "(an unknown id reports status \"NotFound\" and counts as changed). Pitfall: a planning parent " +
+        "goes Running -> WaitingForChildren while its children are still working, so by default " +
+        "waiting on a parent returns early; see treatWaitingForChildrenAsBusy. Requires the calling " +
+        "claude process to run with MCP_TOOL_TIMEOUT >= 930000 (ms) for a long wait to actually be " +
+        "held open -- ClaudeDo's own launchers already set this.")]
     public async Task<WaitForTaskChangeResult> WaitForTaskChange(
-        string[] taskIds, int timeoutSeconds = 60, bool treatWaitingForChildrenAsBusy = false,
+        string[] taskIds,
+        [Description(
+            "How long to wait, in seconds, before giving up. Clamped server-side to 900s (15 min) " +
+            "regardless of what's passed.")]
+        int timeoutSeconds = 60,
+        [Description(
+            "When true, WaitingForChildren still counts as busy, so waiting on a planning parent " +
+            "continues until it reaches WaitingForReview or a terminal status instead of returning " +
+            "as soon as it leaves Running.")]
+        bool treatWaitingForChildrenAsBusy = false,
         CancellationToken cancellationToken = default)
     {
         if (taskIds.Length == 0)
diff --git a/tests/ClaudeDo.Worker.Tests/External/ExternalMcpServiceTests.cs b/tests/ClaudeDo.Worker.Tests/External/ExternalMcpServiceTests.cs
index e6d306d3..4f7ef325 100644
--- a/tests/ClaudeDo.Worker.Tests/External/ExternalMcpServiceTests.cs
+++ b/tests/ClaudeDo.Worker.Tests/External/ExternalMcpServiceTests.cs
@@ -989,19 +989,6 @@ public sealed class ExternalMcpServiceTests : IDisposable
         Assert.Equal(10, result.Config.MaxTurns);
     }
 
-    // ── GetTaskStatusValues ───────────────────────────────────────────────────
-
-    [Fact]
-    public async Task GetTaskStatusValues_ContainsAllStatuses()
-    {
-        var sut = NewService();
-        var values = await sut.GetTaskStatusValues();
-        var names = values.Select(v => v.Status).ToHashSet();
-
-        foreach (var status in Enum.GetValues<TaskStatus>())
-            Assert.Contains(status.ToString(), names);
-    }
-
     // ── ListTasks status filter ───────────────────────────────────────────────
 
     [Fact]