diff --git a/src/main/app/ipc-contracts/organization.ts b/src/main/app/ipc-contracts/organization.ts
index ed1001d1..a5c5bf16 100644
--- a/src/main/app/ipc-contracts/organization.ts
+++ b/src/main/app/ipc-contracts/organization.ts
@@ -45,6 +45,7 @@ export const organizationContracts = {
     requiresFilesystem: z.boolean(), writingMode: z.enum(WRITING_MODE),
   }) satisfies z.ZodType<C.UpdateTaskInput>,
   deleteTask: z.strictObject({ orgId: id, taskId: id }) satisfies z.ZodType<C.DeleteTaskInput>,
+  setTaskBlocked: z.strictObject({ orgId: id, taskId: id, reason: z.string().nullable() }) satisfies z.ZodType<C.SetTaskBlockedInput>,
   updateTaskStatus: z.strictObject({ orgId: id, taskId: id, status: z.enum(TASK_STATUS) }) satisfies z.ZodType<C.UpdateTaskStatusInput>,
   runTask: z.strictObject({ orgId: id, taskId: id }) satisfies z.ZodType<C.RunTaskInput>,
   createGoal: z.strictObject({ orgId: id, title: z.string(), description: z.string(), ownerAgentId: nullableId }) satisfies z.ZodType<C.CreateGoalInput>,
diff --git a/src/main/app/ipc-handlers.ts b/src/main/app/ipc-handlers.ts
index 0ea62a46..5e5ee2c4 100644
--- a/src/main/app/ipc-handlers.ts
+++ b/src/main/app/ipc-handlers.ts
@@ -164,6 +164,7 @@ export function registerIpcHandlers(deps: IpcDeps): void {
   handle("clearIntegrationKey", (input) => mutate(() => integrationKeys.clear(input.name)));
   handle("createTask", (input) => mutate(() => organization.createTask(input)));
   handle("updateTask", (input) => mutate(() => organization.updateTask(input)));
+  handle("setTaskBlocked", (input) => mutate(() => organization.setTaskBlocked(input)));
   handle("deleteTask", (input) => mutate(() => organization.deleteTask(input)));
   handle("updateTaskStatus", (input) => mutate(() => organization.updateTaskStatus(input.orgId, input.taskId, input.status)));
   handle("runTask", async (input) => {
diff --git a/src/main/database/migrations/101-task-blocked.ts b/src/main/database/migrations/101-task-blocked.ts
new file mode 100644
index 00000000..b3d6be1e
--- /dev/null
+++ b/src/main/database/migrations/101-task-blocked.ts
@@ -0,0 +1,7 @@
+// Why the operator blocked a task; while set, no session starts on it.
+export const taskBlockedSchema = `
+  alter table tasks add column blocked_reason text;
+
+  insert into schema_migrations(version, name, applied_at)
+  values (101, 'task_blocked', datetime('now'));
+`;
diff --git a/src/main/database/schema.ts b/src/main/database/schema.ts
index 2e126d74..00a70e3d 100644
--- a/src/main/database/schema.ts
+++ b/src/main/database/schema.ts
@@ -99,6 +99,7 @@ import { dropDrillOnlySloSchema } from "./migrations/097-drop-drill-only-slo";
 import { dropAuditReplaysSchema } from "./migrations/098-drop-audit-replays";
 import { dropRollbackRecordsSchema } from "./migrations/099-drop-rollback-records";
 import { chatReplyRequestsSchema } from "./migrations/100-chat-reply-requests";
+import { taskBlockedSchema } from "./migrations/101-task-blocked";
 
 interface Migration {
   version: number;
@@ -207,6 +208,7 @@ const MIGRATIONS: Migration[] = [
   { version: 98, name: "drop_audit_replays", sql: dropAuditReplaysSchema },
   { version: 99, name: "drop_rollback_records", sql: dropRollbackRecordsSchema },
   { version: 100, name: "chat_reply_requests", sql: chatReplyRequestsSchema },
+  { version: 101, name: "task_blocked", sql: taskBlockedSchema },
 ];
 
 const SCHEMA_VERSION = MIGRATIONS[MIGRATIONS.length - 1].version;
diff --git a/src/main/services/heartbeat-scheduler.ts b/src/main/services/heartbeat-scheduler.ts
index 90fd45bf..4e8b33b9 100644
--- a/src/main/services/heartbeat-scheduler.ts
+++ b/src/main/services/heartbeat-scheduler.ts
@@ -38,6 +38,7 @@ export class HeartbeatScheduler {
       left join provider_usage_windows u
         on u.org_id = p.org_id and u.provider_id = p.id and u.window_start = ?
       where t.status in ('backlog', 'in_progress')
+        and t.blocked_reason is null
         and a.heartbeat_enabled = 1
         and a.lifecycle = 'active'
         and p.enabled = 1
diff --git a/src/main/services/organization-service.ts b/src/main/services/organization-service.ts
index 369f4d2d..a3cecb5f 100644
--- a/src/main/services/organization-service.ts
+++ b/src/main/services/organization-service.ts
@@ -1,7 +1,7 @@
 import type { DatabaseSync } from "node:sqlite";
 import { APPROVAL_STATE, RISK_LEVEL, TASK_STATUS, WRITING_MODE, type RiskLevel } from "../../shared/domain";
 import { createId } from "../../shared/ids";
-import type { CreateAgentInput, CreateGoalInput, CreateOrganizationInput, CreateProjectInput, CreateTaskInput, CreateWorkspaceInput, DeleteTaskInput, UpdateAgentInput, UpdateEmployeeProfileInput, UpdateTaskInput } from "../../shared/commands";
+import type { CreateAgentInput, CreateGoalInput, CreateOrganizationInput, CreateProjectInput, CreateTaskInput, CreateWorkspaceInput, DeleteTaskInput, SetTaskBlockedInput, UpdateAgentInput, UpdateEmployeeProfileInput, UpdateTaskInput } from "../../shared/commands";
 import { AuditService } from "./audit-service";
 import { ensureAgentHeartbeat, resolveGoalKickoff, type GoalKickoffPlan } from "./goal-kickoff";
 import { PolicyService } from "./policy-service";
@@ -472,6 +472,10 @@ export class OrganizationService {
     this.tasks.update(input);
   }
 
+  setTaskBlocked(input: SetTaskBlockedInput): void {
+    this.tasks.setBlocked(input);
+  }
+
   deleteTask(input: DeleteTaskInput): void {
     this.tasks.delete(input);
   }
diff --git a/src/main/services/task-execution-service.ts b/src/main/services/task-execution-service.ts
index 379d5bbb..2817f09b 100644
--- a/src/main/services/task-execution-service.ts
+++ b/src/main/services/task-execution-service.ts
@@ -90,6 +90,7 @@ export class TaskExecutionService {
   async runTask(input: RunTaskInput): Promise<string> {
     const task = requireTask(this.db, input.orgId, input.taskId);
     if (task.status === TASK_STATUS.DONE) throw new Error(`"${task.title}" is done. Reopen it before running it again.`);
+    if (task.blocked_reason !== null) throw new Error(`"${task.title}" is blocked: ${task.blocked_reason} Unblock it to run it.`);
     const inFlight = this.db.prepare("select state from task_runs where task_id = ? and state in ('queued', 'running') limit 1")
       .get(task.id) as { state: string } | undefined;
     if (inFlight) {
@@ -115,6 +116,7 @@ export class TaskExecutionService {
     try {
       const task = requireTask(this.db, orgId, run.task_id);
       if (task.status === TASK_STATUS.DONE) return this.supersedeRun(orgId, runId, run, "the task was closed after this run was queued.");
+      if (task.blocked_reason !== null) return this.supersedeRun(orgId, runId, run, `the task was blocked after this run was queued (${task.blocked_reason}).`);
       if (task.assignee_agent_id !== run.agent_id) {
         return this.supersedeRun(orgId, runId, run, `the task was reassigned after this run was queued (run agent ${run.agent_id}, assignee ${task.assignee_agent_id ?? "none"}).`);
       }
diff --git a/src/main/services/task-holds.ts b/src/main/services/task-holds.ts
index 07662c19..e8fa011f 100644
--- a/src/main/services/task-holds.ts
+++ b/src/main/services/task-holds.ts
@@ -5,7 +5,9 @@ import { budgetBlock, isPriced, providerPrices } from "./spend";
 
 interface OpenTaskRow {
   id: string;
+  status: string;
   stalled_reason: string | null;
+  blocked_reason: string | null;
   enqueue_error: string | null;
   agent_id: string | null;
   provider_id: string | null;
@@ -20,7 +22,7 @@ interface OpenTaskRow {
 export function taskHolds(db: DatabaseSync, now: Date): Map<string, TaskHold> {
   const window = currentProviderUsageWindow(now);
   const rows = db.prepare(`
-    select t.id, t.stalled_reason, t.enqueue_error, a.id as agent_id, p.id as provider_id, p.label as provider_label,
+    select t.id, t.status, t.stalled_reason, t.blocked_reason, t.enqueue_error, a.id as agent_id, p.id as provider_id, p.label as provider_label,
       p.monthly_request_limit as request_limit, coalesce(u.request_count, 0) as request_count,
       c.until_ms as cooldown_until_ms, c.label as cooldown_label
     from tasks t
@@ -28,7 +30,7 @@ export function taskHolds(db: DatabaseSync, now: Date): Map<string, TaskHold> {
     left join providers p on p.id = a.model_provider_id
     left join provider_usage_windows u on u.org_id = p.org_id and u.provider_id = p.id and u.window_start = ?
     left join provider_cooldowns c on c.provider_id = p.id
-    where t.status in ('backlog', 'in_progress')
+    where (t.status in ('backlog', 'in_progress') or (t.status = 'review' and t.blocked_reason is not null))
       and not exists (select 1 from task_runs r where r.task_id = t.id and r.state = 'running')
   `).all(window.start) as unknown as OpenTaskRow[];
   const budgets = new Map<string, MoneyBlock | null>();
@@ -60,6 +62,9 @@ interface MoneyBlock {
 }
 
 function holdOf(row: OpenTaskRow, now: Date, windowEnd: string, budget: (agentId: string, providerId: string) => MoneyBlock | null): TaskHold | null {
+  if (row.blocked_reason) return { reason: `Blocked: ${row.blocked_reason}`, resumesAt: null, waitingOn: "operator" };
+  // Work in review waits on its reviewer, so only a block holds it here.
+  if (row.status === "review") return null;
   if (row.stalled_reason) return { reason: row.stalled_reason, resumesAt: null, waitingOn: "operator" };
   if (row.enqueue_error) return { reason: `Could not start: ${row.enqueue_error}`, resumesAt: null, waitingOn: "operator" };
   if (!row.agent_id || !row.provider_id) return null;
diff --git a/src/main/services/task-mutations.ts b/src/main/services/task-mutations.ts
index 4b28268b..07160bba 100644
--- a/src/main/services/task-mutations.ts
+++ b/src/main/services/task-mutations.ts
@@ -1,6 +1,6 @@
 import type { DatabaseSync } from "node:sqlite";
 import { RISK_LEVEL, TASK_STATUS, type TaskPriority } from "../../shared/domain";
-import type { CreateTaskInput, DeleteTaskInput, UpdateTaskInput } from "../../shared/commands";
+import type { CreateTaskInput, DeleteTaskInput, SetTaskBlockedInput, UpdateTaskInput } from "../../shared/commands";
 import { AuditService } from "./audit-service";
 import { withSavepoint } from "../database/connection";
 import { heldWorkTitles } from "./held-deliverables";
@@ -70,6 +70,26 @@ export class TaskMutations {
     });
   }
 
+  /** Blocks the task with a reason (no session starts, queued ones are superseded) or unblocks it with null. */
+  setBlocked(input: SetTaskBlockedInput): void {
+    const reason = input.reason === null ? null : input.reason.trim();
+    if (reason === "") throw new Error("Say why the task is blocked.");
+    withSavepoint(this.db, "task_block", () => {
+      const result = this.db.prepare("update tasks set blocked_reason = ?, updated_at = ? where id = ? and org_id = ?").run(reason, new Date().toISOString(), input.taskId, input.orgId);
+      if (result.changes === 0) throw new Error("Task was not found.");
+      if (reason !== null) {
+        this.db.prepare(`
+          update task_runs set state = 'superseded', completed_at = ?, error_message = ?
+          where task_id = ? and org_id = ? and state = 'queued'
+        `).run(new Date().toISOString(), `Superseded: the task was blocked (${reason}).`, input.taskId, input.orgId);
+      }
+      this.audit.record({
+        orgId: input.orgId, entityType: "task", entityId: input.taskId, actorType: "employee", actorId: null,
+        action: reason === null ? "unblocked" : "blocked", payload: { reason },
+      });
+    });
+  }
+
   delete(input: DeleteTaskInput): void {
     const running = this.db.prepare("select 1 from task_runs where task_id = ? and org_id = ? and state = 'running' limit 1")
       .get(input.taskId, input.orgId);
diff --git a/src/main/services/task-prompts.ts b/src/main/services/task-prompts.ts
index eef54414..d2d1505a 100644
--- a/src/main/services/task-prompts.ts
+++ b/src/main/services/task-prompts.ts
@@ -21,6 +21,7 @@ export interface TaskExecutionTaskRow {
   writing_mode: WritingMode;
   handoff_json: string | null;
   origin: string | null;
+  blocked_reason: string | null;
 }
 
 export interface TaskExecutionAgentRow {
diff --git a/src/preload/index.ts b/src/preload/index.ts
index fe325585..3713cff9 100644
--- a/src/preload/index.ts
+++ b/src/preload/index.ts
@@ -90,6 +90,7 @@ const api: DesktopApi = {
   runRequests: (input) => invoke(IPC_CHANNELS.runRequests, input),
   chatThreadHistory: (input) => invoke(IPC_CHANNELS.chatThreadHistory, input),
   chatSpaceHistory: (input) => invoke(IPC_CHANNELS.chatSpaceHistory, input),
+  setTaskBlocked: (input) => invoke(IPC_CHANNELS.setTaskBlocked, input),
   revokeConnector: (input) => invoke(IPC_CHANNELS.revokeConnector, input),
   refreshComposioAccounts: (input) => invoke(IPC_CHANNELS.refreshComposioAccounts, input),
   search: (input) => invoke(IPC_CHANNELS.search, input),
diff --git a/src/renderer/src/i18n/zh.ts b/src/renderer/src/i18n/zh.ts
index a6cc3fe4..d508ccda 100644
--- a/src/renderer/src/i18n/zh.ts
+++ b/src/renderer/src/i18n/zh.ts
@@ -31,6 +31,14 @@ export const zh: Record<string, string> = {
   "Writing": "写作方式",
   "superseded": "已被取代",
   "stalled": "已停滞",
+  "blocked": "已阻塞",
+  "Block": "阻塞",
+  "Unblock": "解除阻塞",
+  "Block task": "阻塞任务",
+  "Why is it blocked?": "为什么阻塞？",
+  "Send back": "退回",
+  "Reopen": "重新打开",
+  "Back to backlog": "退回待办",
   "needs you": "待你处理",
   "waiting": "等待中",
   "Resumes on its own at {time}.": "将于 {time} 自动恢复。",
diff --git a/src/renderer/src/pages/WorkPage.tsx b/src/renderer/src/pages/WorkPage.tsx
index d4477261..fa930994 100644
--- a/src/renderer/src/pages/WorkPage.tsx
+++ b/src/renderer/src/pages/WorkPage.tsx
@@ -177,6 +177,12 @@ export function WorkPage({ snapshot, actions, navigate, focus }: PageProps) {
         onAdvance={advance}
         onRun={runTask}
         onOpenTask={setDetailTaskId}
+        onMove={async (task, status) => {
+          await actions.run(() => window.agentCompany.updateTaskStatus({ orgId, taskId: task.id, status }));
+        }}
+        onBlock={async (task, reason) => {
+          await actions.run(() => window.agentCompany.setTaskBlocked({ orgId, taskId: task.id, reason }));
+        }}
         onScope={(next) => {
           setScope(next);
           setDetailTaskId(null);
@@ -357,7 +363,10 @@ function TaskCard({
       <div className="row" style={{ flexWrap: "wrap", gap: 6, minWidth: 0 }}>
         {project ? <Pill>{project.name}</Pill> : <Pill>{capitalize(task.risk)}</Pill>}
         {task.stalledReason && task.status !== "done" && <Pill tone="red">{t("stalled")}</Pill>}
-        {task.hold && !task.stalledReason && (
+        {task.blockedReason && task.status !== "done" && (
+          <span title={task.blockedReason} style={{ display: "inline-flex" }}><Pill tone="red">{t("blocked")}</Pill></span>
+        )}
+        {task.hold && !task.stalledReason && !task.blockedReason && (
           <span title={task.hold.reason} style={{ display: "inline-flex" }}>
             <Pill tone={task.hold.waitingOn === "operator" ? "red" : "amber"}>{task.hold.waitingOn === "operator" ? t("needs you") : t("waiting")}</Pill>
           </span>
diff --git a/src/renderer/src/pages/work/TaskDetailDialog.tsx b/src/renderer/src/pages/work/TaskDetailDialog.tsx
index 8251054c..a0b395c9 100644
--- a/src/renderer/src/pages/work/TaskDetailDialog.tsx
+++ b/src/renderer/src/pages/work/TaskDetailDialog.tsx
@@ -12,7 +12,7 @@ import type {
   TaskRunRecord,
   WorkspaceRecord,
 } from "../../../../shared/domain";
-import { TASK_STATUS, type WritingMode } from "../../../../shared/domain";
+import { TASK_STATUS, type TaskStatus, type WritingMode } from "../../../../shared/domain";
 import { auditEventLabel, formatRelative } from "../types";
 import { WRITING_OPTIONS, descendantIds, nextStatus, prettyRunState, prettyStatus, providerFor, runBlocker, runsForTask, runTone } from "./task-helpers";
 import type { SnapshotActions } from "../../app/useSnapshot";
@@ -43,6 +43,8 @@ export function TaskDetailDialog({
   onAdvance,
   onRun,
   onOpenTask,
+  onMove,
+  onBlock,
   onScope,
   navigate,
 }: {
@@ -62,10 +64,20 @@ export function TaskDetailDialog({
   onAdvance: (task: TaskRecord) => void;
   onRun: (task: TaskRecord) => void;
   onOpenTask: (taskId: string) => void;
+  /** Moves the task to any status, backwards included: send back, reopen, back to backlog. */
+  onMove: (task: TaskRecord, status: TaskStatus) => Promise<void>;
+  /** Blocks the task with a reason, or unblocks it with null. */
+  onBlock: (task: TaskRecord, reason: string | null) => Promise<void>;
   onScope: (scope: Focus) => void;
   navigate: PageProps["navigate"];
 }) {
   const [tab, setTab] = useState<Tab>("overview");
+  const [blocking, setBlocking] = useState(false);
+  const [actionError, setActionError] = useState<string | null>(null);
+  const act = (operation: () => Promise<void>, after?: () => void) => {
+    setActionError(null);
+    operation().then(after, (error: unknown) => setActionError(error instanceof Error ? error.message : String(error)));
+  };
   const [editing, setEditing] = useState(false);
   const [editError, setEditError] = useState<string | null>(null);
 
@@ -148,8 +160,30 @@ export function TaskDetailDialog({
           <ActivityTab audit={taskAudit} approvals={taskApprovals} onOpenApproval={(approvalId) => navigate("approvals", { kind: "approval", id: approvalId })} />
         )}
 
+        {blocking && (
+          <form
+            className="row"
+            style={{ gap: 8, marginTop: 12 }}
+            onSubmit={(event) => {
+              event.preventDefault();
+              const reason = String(new FormData(event.currentTarget).get("reason") ?? "");
+              act(() => onBlock(task, reason), () => setBlocking(false));
+            }}
+          >
+            <input className="input" name="reason" aria-label={t("Why is it blocked?")} placeholder={t("Why is it blocked?")} required autoFocus style={{ flex: 1 }} />
+            <Button tone="primary" size="small" type="submit">{t("Block task")}</Button>
+            <Button tone="ghost" size="small" onClick={() => setBlocking(false)}>{t("Cancel")}</Button>
+          </form>
+        )}
+        {actionError && <div className="form-error" role="alert" style={{ marginTop: 8 }}>{actionError}</div>}
         <div className="modal-actions">
           <Button tone="ghost" onClick={deleteTask}><Icon name="x" size={16} /> {t("Delete")}</Button>
+          {task.blockedReason
+            ? <Button onClick={() => act(() => onBlock(task, null))}>{t("Unblock")}</Button>
+            : task.status !== TASK_STATUS.DONE && !blocking && <Button onClick={() => setBlocking(true)}>{t("Block")}</Button>}
+          {task.status === TASK_STATUS.REVIEW && <Button onClick={() => act(() => onMove(task, TASK_STATUS.IN_PROGRESS))}>{t("Send back")}</Button>}
+          {task.status === TASK_STATUS.DONE && <Button onClick={() => act(() => onMove(task, TASK_STATUS.IN_PROGRESS))}>{t("Reopen")}</Button>}
+          {task.status === TASK_STATUS.IN_PROGRESS && <Button onClick={() => act(() => onMove(task, TASK_STATUS.BACKLOG))}>{t("Back to backlog")}</Button>}
           {assignee && <Button onClick={() => onRun(task)} disabled={runBlocker(task, provider, taskRuns) !== null}><Icon name="send" size={16} /> {t("Run")}</Button>}
           {advanceTo && <Button tone="primary" onClick={() => onAdvance(task)}><Icon name="check" size={16} /> {prettyStatus(advanceTo)}</Button>}
         </div>
diff --git a/src/shared/commands/organization.ts b/src/shared/commands/organization.ts
index ea74129e..3a5a70a5 100644
--- a/src/shared/commands/organization.ts
+++ b/src/shared/commands/organization.ts
@@ -123,6 +123,13 @@ export interface UpdateTaskInput {
   writingMode: WritingMode;
 }
 
+export interface SetTaskBlockedInput {
+  orgId: string;
+  taskId: string;
+  /** Why the task is blocked; null unblocks it. */
+  reason: string | null;
+}
+
 export interface DeleteTaskInput {
   orgId: string;
   taskId: string;
diff --git a/src/shared/desktop-api.ts b/src/shared/desktop-api.ts
index 5801c509..f11562ff 100644
--- a/src/shared/desktop-api.ts
+++ b/src/shared/desktop-api.ts
@@ -34,6 +34,7 @@ import type {
   DeleteAutomationRuleInput,
   DeleteDocumentInput,
   DeleteTaskInput,
+  SetTaskBlockedInput,
   DeleteKnowledgeEntryInput,
   ResumeGoalInput,
   UpdateAutomationRuleInput,
@@ -199,6 +200,8 @@ export interface DesktopApi {
   /** One thread in full, beyond the snapshot's recent window. */
   chatThreadHistory(input: { orgId: string; threadId: string }): Promise<DesktopResult<ThreadHistory>>;
   /** The page of a conversation before a loaded message, for history older than the snapshot holds. */
+  /** Blocks a task with a reason, or unblocks it with null. */
+  setTaskBlocked(input: SetTaskBlockedInput): Promise<DesktopResult<AppSnapshot>>;
   chatSpaceHistory(input: { orgId: string; spaceId: string; beforeMessageId: string | null } & ({ limit: number } | { fromMessageId: string })): Promise<DesktopResult<SpaceHistoryPage>>;
   revokeConnector(input: RevokeConnectorInput): Promise<DesktopResult<AppSnapshot>>;
   search(input: SearchInput): Promise<DesktopResult<SearchResultRecord[]>>;
diff --git a/src/shared/domain.ts b/src/shared/domain.ts
index 8be36b57..774bb5da 100644
--- a/src/shared/domain.ts
+++ b/src/shared/domain.ts
@@ -108,6 +108,8 @@ export interface TaskRecord {
   stalledReason: string | null;
   /** Why the heartbeat last failed to queue the task; cleared once it queues. */
   enqueueError: string | null;
+  /** Why the operator blocked the task; no session starts while it is set. */
+  blockedReason: string | null;
   /** Why the open task is not moving now, or null when nothing holds it. */
   hold: TaskHold | null;
   /** Runs at or below this task_runs rowid no longer count toward the run budget. */
diff --git a/src/shared/ipc.ts b/src/shared/ipc.ts
index 147d0fb4..9d0d51a5 100644
--- a/src/shared/ipc.ts
+++ b/src/shared/ipc.ts
@@ -83,6 +83,7 @@ export const IPC_CHANNELS = {
   runRequests: "agentcompany:run-requests",
   chatThreadHistory: "agentcompany:chat-thread-history",
   chatSpaceHistory: "agentcompany:chat-space-history",
+  setTaskBlocked: "agentcompany:set-task-blocked",
   revokeConnector: "agentcompany:revoke-connector",
   search: "agentcompany:search",
   rendererEvent: "agentcompany:renderer-event",
diff --git a/tests/e2e/ceo-chat.spec.ts b/tests/e2e/ceo-chat.spec.ts
index cd6e440f..398a01d6 100644
--- a/tests/e2e/ceo-chat.spec.ts
+++ b/tests/e2e/ceo-chat.spec.ts
@@ -95,6 +95,16 @@ test("the pinned CEO conversation is the Messages front door", async () => {
       return [task.writingMode, task.requiresFilesystem];
     });
     expect(edited).toEqual(["technical", true]);
+    // Blocking says why on the task and stops it; work can also move backwards.
+    await taskDialog.getByRole("button", { name: "Block", exact: true }).click();
+    await taskDialog.getByRole("textbox", { name: "Why is it blocked?" }).fill("Waiting for the legal review.");
+    await taskDialog.getByRole("button", { name: "Block task" }).click();
+    await expect(taskDialog.getByRole("status")).toContainText("Blocked: Waiting for the legal review.");
+    await taskDialog.getByRole("button", { name: "Unblock" }).click();
+    await expect(taskDialog.getByText("Blocked: Waiting for the legal review.")).toHaveCount(0);
+    await taskDialog.getByRole("button", { name: "In progress" }).click();
+    await taskDialog.getByRole("button", { name: "Back to backlog" }).click();
+    await expect(taskDialog.getByRole("button", { name: "In progress" })).toBeVisible();
     await taskDialog.getByRole("button", { name: "Close" }).click();
     await page.getByRole("button", { name: "Messages" }).click();
 
diff --git a/tests/integration/task-holds.test.ts b/tests/integration/task-holds.test.ts
index 86338bc3..45683332 100644
--- a/tests/integration/task-holds.test.ts
+++ b/tests/integration/task-holds.test.ts
@@ -8,6 +8,7 @@ import { ProviderService } from "../../src/main/services/provider-service";
 import { providerAdapters } from "../../src/main/services/provider-adapters";
 import { TaskExecutionService } from "../../src/main/services/task-execution-service";
 import { SnapshotService } from "../../src/main/services/snapshot-service";
+import { OrganizationService } from "../../src/main/services/organization-service";
 import { currentProviderUsageWindow } from "../../src/shared/provider-runtime-domain";
 import type { AgentTurnResult } from "../../src/main/services/provider-tool-turn";
 
@@ -106,3 +107,29 @@ describe("why an open task is not moving", () => {
     h.connection.close();
   });
 });
+
+describe("blocking a task", () => {
+  test("stops it until unblocked: no new session, queued ones superseded, manual runs refused, and the board says why", async () => {
+    const h = company();
+    const organization = new OrganizationService(h.connection.db);
+    expect(h.connection.transaction(() => h.execution.enqueueHeartbeatRuns())).toHaveLength(1);
+    h.connection.transaction(() => organization.setTaskBlocked({ orgId: h.orgId, taskId: h.taskId, reason: "Waiting for the legal review." }));
+    expect(h.connection.db.prepare("select state from task_runs where task_id = ? order by rowid desc limit 1").get(h.taskId)).toEqual({ state: "superseded" });
+    expect(h.hold()).toEqual({ reason: "Blocked: Waiting for the legal review.", resumesAt: null, waitingOn: "operator" });
+    expect(h.connection.transaction(() => h.execution.enqueueHeartbeatRuns())).toEqual([]);
+    await expect(h.execution.runTask({ orgId: h.orgId, taskId: h.taskId })).rejects.toThrow("is blocked: Waiting for the legal review. Unblock it to run it.");
+    expect(() => organization.setTaskBlocked({ orgId: h.orgId, taskId: h.taskId, reason: "  " })).toThrow("Say why the task is blocked.");
+
+    h.connection.transaction(() => organization.setTaskBlocked({ orgId: h.orgId, taskId: h.taskId, reason: null }));
+    expect(h.hold()).toBeNull();
+    // Work in review can be blocked too, and says so.
+    h.connection.db.prepare("update tasks set status = 'review' where id = ?").run(h.taskId);
+    h.connection.transaction(() => organization.setTaskBlocked({ orgId: h.orgId, taskId: h.taskId, reason: "Spec changed." }));
+    expect(h.hold()).toEqual({ reason: "Blocked: Spec changed.", resumesAt: null, waitingOn: "operator" });
+    h.connection.transaction(() => organization.setTaskBlocked({ orgId: h.orgId, taskId: h.taskId, reason: null }));
+    expect(h.hold()).toBeNull();
+    h.connection.db.prepare("update tasks set status = 'backlog' where id = ?").run(h.taskId);
+    expect(h.connection.transaction(() => h.execution.enqueueHeartbeatRuns())).toHaveLength(1);
+    h.connection.close();
+  });
+});
diff --git a/tests/unit/domain-services.test.ts b/tests/unit/domain-services.test.ts
index 226cc7ac..6d0b30bf 100644
--- a/tests/unit/domain-services.test.ts
+++ b/tests/unit/domain-services.test.ts
@@ -35,7 +35,7 @@ describe("domain services", () => {
     const connection = createConnection();
 
     const rows = connection.db.prepare("select version from schema_migrations order by version asc").all() as Array<{ version: number }>;
-    expect(rows.map((row) => row.version)).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]);
+    expect(rows.map((row) => row.version)).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101]);
     connection.close();
   });