feat(FN-5233): add tombstone recreate guard and allow-resurrection delete f

Implements the FN-5233 tombstone system for soft-delete resurrection: a configurable `tombstoneWindowSeconds` deduplicates recreation of recently deleted tasks, with an `allowResurrection` flag that permits explicit resurrect-on-recreate, tombstone recreate guards in the store layer, and cleanup of Fusion-Task-Id: FN-5233
2026-05-21 21:35:11 -07:00
parent 916047c2ae
commit 2d2e5b809f
18 changed files with 603 additions and 29 deletions
--- a/packages/cli/skill/fusion/references/extension-tools.md
+++ b/packages/cli/skill/fusion/references/extension-tools.md
@@ -118,11 +118,12 @@ Unarchive an archived task (move from archived → done). Restores the task to t

 ### fn_task_delete

-Soft-delete a task from active Fusion board views. The task row and artifacts are preserved, and the task ID remains reserved for potential operator recovery.
+Soft-delete a task from active Fusion board views. The task row and artifacts are preserved; optional allowResurrection marks the ID for intentional recreation.

 | Parameter | Type | Required | Description |
 |-----------|------|----------|-------------|
 | `id` | string | ✓ | Task ID to delete (e.g. FN-001) |
+| `allowResurrection` | boolean | — | When true, mark this tombstone as explicitly reusable for future recreation. |

 ### fn_task_plan

--- a/packages/cli/skill/fusion/references/fusion-capabilities.md
+++ b/packages/cli/skill/fusion/references/fusion-capabilities.md
@@ -24,7 +24,7 @@ All skill/extension tool invocations in this catalog use the public `fn_*` names
 | `fn_task_refine` | Request a refinement of a completed or in-review task. Creates a new follow-up task in planning that references the original task as a dependency. Use this when a done or in-review task needs additional work, improvements, or follow-up changes. |
 | `fn_task_archive` | Archive a done task (move from done → archived). Archived tasks are preserved for historical reference but moved out of the main board view. |
 | `fn_task_unarchive` | Unarchive an archived task (move from archived → done). Restores the task to the done column. |
-| `fn_task_delete` | Soft-delete a task from active Fusion board views. The task row and artifacts are preserved, and the task ID remains reserved for potential operator recovery. |
+| `fn_task_delete` | Soft-delete a task from active Fusion board views. The task row and artifacts are preserved; optional allowResurrection marks the ID for intentional recreation. |
 | `fn_task_import_github` | Import GitHub issues as Fusion tasks. Fetches open issues from a repository and creates tasks in the planning column. Each task includes the issue title and body with a link to the source issue. |
 | `fn_task_import_github_issue` | Import a specific GitHub issue as a Fusion task. Fetches the issue by number and creates a single task in the planning column with the issue title and body. |
 | `fn_task_browse_github_issues` | List open GitHub issues from a repository to browse before importing. Returns issue numbers, titles, and URLs for selection. Use with fn_task_import_github_issue to import specific issues by number. |
--- a/packages/cli/src/tests/bin.test.ts
+++ b/packages/cli/src/tests/bin.test.ts
@@ -650,6 +650,16 @@ describe("bin command routing and fallbacks", () => {
    expect(errorSpy).toHaveBeenCalledWith(expect.stringContaining("Usage: fn pr create <task-id>"));
  });

+  it("routes task delete with allow-resurrection flag", async () => {
+    await runBin(["task", "delete", "FN-1", "--force", "--allow-resurrection"]);
+    expect(commandMocks.runTaskDelete).toHaveBeenCalledWith("FN-1", true, true, undefined);
+  });
+
+  it("routes task delete default allow-resurrection=false", async () => {
+    await runBin(["task", "delete", "FN-1", "--force"]);
+    expect(commandMocks.runTaskDelete).toHaveBeenCalledWith("FN-1", true, false, undefined);
+  });
+
  it("routes desktop flags to runDesktop", async () => {
    await runBin(["desktop", "--dev", "--paused", "--interactive"]);
    expect(commandMocks.runDesktop).toHaveBeenCalledWith({
--- a/packages/cli/src/tests/task-delete-allow-resurrection.test.ts
+++ b/packages/cli/src/tests/task-delete-allow-resurrection.test.ts
@@ -0,0 +1,71 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { mkdtemp, mkdir, rm } from "node:fs/promises";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+
+import { TaskStore } from "@fusion/core";
+import kbExtension from "../extension.js";
+
+type RegisteredTool = {
+  name: string;
+  execute: (toolCallId: string, params: any, signal: AbortSignal | undefined, onUpdate: any, ctx: { cwd: string }) => Promise<any>;
+};
+
+function createMockAPI() {
+  const tools = new Map<string, RegisteredTool>();
+  return {
+    tools,
+    registerTool(tool: RegisteredTool) {
+      tools.set(tool.name, tool);
+    },
+    registerCommand() {
+      // no-op for tests
+    },
+    on() {
+      // no-op for tests
+    },
+  } as any;
+}
+
+describe("task delete allowResurrection plumbing", () => {
+  let rootDir: string;
+
+  beforeEach(async () => {
+    rootDir = await mkdtemp(join(tmpdir(), "fn-task-delete-allow-"));
+    await mkdir(join(rootDir, ".fusion"), { recursive: true });
+  });
+
+  afterEach(async () => {
+    await rm(rootDir, { recursive: true, force: true });
+  });
+
+  it("fn_task_delete forwards allowResurrection=true", async () => {
+    const store = new TaskStore(rootDir);
+    await store.init();
+    const task = await store.createTask({ title: "x", description: "y", column: "todo" });
+
+    const api = createMockAPI();
+    kbExtension(api);
+    const tool = api.tools.get("fn_task_delete") as RegisteredTool;
+    await tool.execute("call-1", { id: task.id, allowResurrection: true }, undefined, undefined, { cwd: rootDir });
+
+    const deleted = (store as any).readTaskFromDb(task.id, { includeDeleted: true }) as { allowResurrection?: boolean; deletedAt?: string };
+    expect(deleted.deletedAt).toBeTruthy();
+    expect(deleted.allowResurrection).toBe(true);
+  });
+
+  it("fn_task_delete defaults allowResurrection=false", async () => {
+    const store = new TaskStore(rootDir);
+    await store.init();
+    const task = await store.createTask({ title: "x", description: "y", column: "todo" });
+
+    const api = createMockAPI();
+    kbExtension(api);
+    const tool = api.tools.get("fn_task_delete") as RegisteredTool;
+    await tool.execute("call-2", { id: task.id }, undefined, undefined, { cwd: rootDir });
+
+    const deleted = (store as any).readTaskFromDb(task.id, { includeDeleted: true }) as { allowResurrection?: boolean; deletedAt?: string };
+    expect(deleted.deletedAt).toBeTruthy();
+    expect(deleted.allowResurrection).toBeUndefined();
+  });
+});
--- a/packages/cli/src/bin.ts
+++ b/packages/cli/src/bin.ts
@@ -275,7 +275,8 @@ Usage:
  fn task refine <id> [opts]          Create a refinement task from done/in-review
  fn task archive <id>                Archive a done task
  fn task unarchive <id>              Unarchive an archived task
-  fn task delete <id> [--force]       Delete a task (use --force to skip confirmation)
+  fn task delete <id> [--force] [--allow-resurrection]
+                                      Delete a task (use --force to skip confirmation; --allow-resurrection permits intentional ID recreation)
  fn task attach <id> <file>          Attach a file to a task
  fn task pause <id>                  Pause a task (stops all automation)
  fn task unpause <id>                Unpause a task (resumes automation)
@@ -1138,9 +1139,10 @@ async function main() {
          }
          case "delete": {
            const id = args[2];
-            if (!id) { console.error("Usage: fn task delete <id> [--force]"); process.exit(1); }
+            if (!id) { console.error("Usage: fn task delete <id> [--force] [--allow-resurrection]"); process.exit(1); }
            const force = args.includes("--force");
-            await runTaskDelete(id, force, projectName);
+            const allowResurrection = args.includes("--allow-resurrection");
+            await runTaskDelete(id, force, allowResurrection, projectName);
            break;
          }
          case "attach": {
--- a/packages/cli/src/commands/task.ts
+++ b/packages/cli/src/commands/task.ts
@@ -1023,7 +1023,7 @@ export async function runTaskRetry(id: string, projectName?: string) {
  console.log();
 }

-export async function runTaskDelete(id: string, force?: boolean, projectName?: string) {
+export async function runTaskDelete(id: string, force?: boolean, allowResurrection?: boolean, projectName?: string) {
  const store = await getStore(projectName);

  // Check if task exists first
@@ -1051,6 +1051,7 @@ export async function runTaskDelete(id: string, force?: boolean, projectName?: s

  try {
    await store.deleteTask(id, {
+      allowResurrection: allowResurrection === true,
      auditContext: {
        agentId: "cli",
        runId: `synthetic-cli-delete-${id}-${Date.now()}`,
--- a/packages/cli/src/extension.ts
+++ b/packages/cli/src/extension.ts
@@ -1177,22 +1177,24 @@ export default function kbExtension(pi: ExtensionAPI) {
    label: "fn: Delete Task",
    description:
      "Soft-delete a task from active Fusion board views. " +
-      "The task row and artifacts are preserved, and the task ID remains reserved for potential operator recovery.",
+      "The task row and artifacts are preserved; optional allowResurrection marks the ID for intentional recreation.",
    promptSnippet: "Soft-delete a Fusion task",
    promptGuidelines: [
      "Use for cleaning up test tasks or tasks created in error when you want the task hidden from active board views",
      "This tool performs a soft delete: task data is preserved and the ID stays reserved",
-      "Tasks cannot be undeleted through the current pi/CLI tool surface",
+      "Use allowResurrection:true when operators want the deleted task ID to be intentionally reusable on future createTask calls",
      "Use fn_task_archive for completed work you want to keep referenceable in the board",
      "True hard removal is handled by archive cleanup paths (archiveTaskAndCleanup / cleanupArchivedTasks), not fn_task_delete",
    ],
    parameters: Type.Object({
      id: Type.String({ description: "Task ID to delete (e.g. FN-001)" }),
+      allowResurrection: Type.Optional(Type.Boolean({ description: "When true, mark this tombstone as explicitly reusable for future recreation." })),
    }),

    async execute(_toolCallId, params, _signal, _onUpdate, ctx) {
      const store = await getStore(ctx.cwd);
      const task = await store.deleteTask(params.id, {
+        allowResurrection: params.allowResurrection === true,
        auditContext: {
          agentId: "pi-extension",
          runId: `synthetic-pi-delete-${params.id}-${Date.now()}`,
--- a/packages/core/src/tests/duplicate-intake-tombstone-window.test.ts
+++ b/packages/core/src/tests/duplicate-intake-tombstone-window.test.ts
@@ -0,0 +1,135 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import { TombstonedTaskResurrectionError } from "../store.js";
+import { createTaskStoreTestHarness } from "./store-test-helpers.js";
+
+describe("FN-5233 tombstone sticky-window duplicate intake", () => {
+  const harness = createTaskStoreTestHarness();
+
+  beforeEach(async () => {
+    await harness.beforeEach();
+  });
+
+  afterEach(async () => {
+    vi.useRealTimers();
+    await harness.afterEach();
+  });
+
+  it("refuses near-duplicate intake against recent tombstone and records intake:resurrection-blocked", async () => {
+    const store = harness.store();
+    await store.updateSettings({ tombstoneStickyWindowDays: 7 });
+
+    const original = await store.createTask({
+      title: "Memory leak in merge worker",
+      description: "Fix memory leak in merge worker when queue is drained",
+      source: { sourceType: "unknown", sourceAgentId: "agent-1" },
+    });
+    await store.deleteTask(original.id);
+
+    await expect(store.createTask({
+      title: "Memory leak in merge worker",
+      description: "Fix memory leak in merge worker when queue is drained",
+      source: { sourceType: "unknown", sourceAgentId: "agent-1" },
+    })).rejects.toBeInstanceOf(TombstonedTaskResurrectionError);
+
+    const events = (store as any).db.prepare(
+      "SELECT mutationType FROM runAuditEvents WHERE mutationType = 'intake:resurrection-blocked'"
+    ).all() as Array<{ mutationType: string }>;
+    expect(events).toHaveLength(1);
+  });
+
+  it("allows intake when sticky window is disabled", async () => {
+    const store = harness.store();
+    await store.updateSettings({ tombstoneStickyWindowDays: 0 });
+
+    const original = await store.createTask({
+      title: "A",
+      description: "same text",
+      source: { sourceType: "unknown", sourceAgentId: "agent-2" },
+    });
+    await store.deleteTask(original.id);
+
+    await expect(store.createTask({
+      title: "A",
+      description: "same text",
+      source: { sourceType: "unknown", sourceAgentId: "agent-2" },
+    })).resolves.toMatchObject({ id: expect.any(String) });
+  });
+
+  it("ignores tombstones outside sticky window", async () => {
+    vi.useFakeTimers();
+    const oldNow = new Date("2026-01-01T00:00:00.000Z");
+    vi.setSystemTime(oldNow);
+    const store = harness.store();
+    await store.updateSettings({ tombstoneStickyWindowDays: 7 });
+    const original = await store.createTask({
+      title: "Old tombstone",
+      description: "same text",
+      source: { sourceType: "unknown", sourceAgentId: "agent-2b" },
+    });
+    await store.deleteTask(original.id);
+
+    vi.setSystemTime(new Date("2026-01-12T00:00:00.000Z"));
+    await expect(store.createTask({
+      title: "Old tombstone",
+      description: "same text",
+      source: { sourceType: "unknown", sourceAgentId: "agent-2b" },
+    })).resolves.toMatchObject({ id: expect.any(String) });
+  });
+
+  it("allows intake when tombstoned match has allowResurrection unlock", async () => {
+    const store = harness.store();
+    await store.updateSettings({ tombstoneStickyWindowDays: 7 });
+
+    const original = await store.createTask({
+      title: "Refactor parser",
+      description: "Refactor parser for streaming input",
+      source: { sourceType: "unknown", sourceAgentId: "agent-3" },
+    });
+    await store.deleteTask(original.id, { allowResurrection: true });
+
+    await expect(store.createTask({
+      title: "Refactor parser",
+      description: "Refactor parser for streaming input",
+      source: { sourceType: "unknown", sourceAgentId: "agent-3" },
+    })).resolves.toMatchObject({ id: expect.any(String) });
+  });
+
+  it("keeps live-task duplicate behavior (auto-archive) unchanged", async () => {
+    const store = harness.store();
+    const live = await store.createTask({
+      title: "Live dup",
+      description: "duplicate text",
+      source: { sourceType: "unknown", sourceAgentId: "agent-4" },
+    });
+    const dup = await store.createTask({
+      title: "Live dup",
+      description: "duplicate text",
+      source: { sourceType: "unknown", sourceAgentId: "agent-4" },
+    });
+    expect(dup.column).toBe("archived");
+    const events = (store as any).db.prepare("SELECT mutationType FROM runAuditEvents WHERE mutationType = 'intake:resurrection-blocked'").all() as Array<{ mutationType: string }>;
+    expect(events).toHaveLength(0);
+    expect(live.id).not.toBe(dup.id);
+  });
+
+  it("fails open when tombstone widening query errors", async () => {
+    const store = harness.store();
+    const db = (store as any).db;
+    const originalPrepare = db.prepare.bind(db);
+    db.prepare = (sql: string) => {
+      if (sql.includes("deletedAt IS NOT NULL") && sql.includes("sourceAgentId")) {
+        throw new Error("synthetic tombstone query failure");
+      }
+      return originalPrepare(sql);
+    };
+
+    await expect(store.createTask({
+      title: "Fallback path",
+      description: "create despite widening failure",
+      source: { sourceType: "unknown", sourceAgentId: "agent-5" },
+    })).resolves.toMatchObject({ id: expect.any(String) });
+
+    db.prepare = originalPrepare;
+  });
+});
--- a/packages/core/src/tests/soft-delete-resurrection-FN-5233.test.ts
+++ b/packages/core/src/tests/soft-delete-resurrection-FN-5233.test.ts
@@ -0,0 +1,89 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+
+import { TombstonedTaskResurrectionError } from "../store.js";
+import { createTaskStoreTestHarness } from "./store-test-helpers.js";
+
+describe("FN-5233 tombstoned createTask behavior", () => {
+  const harness = createTaskStoreTestHarness();
+
+  beforeEach(async () => {
+    await harness.beforeEach();
+  });
+
+  afterEach(async () => {
+    await harness.afterEach();
+  });
+
+  it("throws TombstonedTaskResurrectionError when recreating a tombstoned id", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ title: "a", description: "alpha", column: "todo" });
+    await store.deleteTask(task.id);
+    const created: string[] = [];
+    store.on("task:created", (event) => created.push(event.id));
+
+    await expect(
+      store.createTaskWithReservedId({ title: "b", description: "beta", column: "todo" }, { taskId: task.id }),
+    ).rejects.toBeInstanceOf(TombstonedTaskResurrectionError);
+
+    const row = (store as any).db.prepare("SELECT deletedAt, allowResurrection FROM tasks WHERE id = ?").get(task.id) as {
+      deletedAt: string | null;
+      allowResurrection: number;
+    };
+    expect(row.deletedAt).toBeTruthy();
+    expect(row.allowResurrection).toBe(0);
+    expect(created).toEqual([]);
+  });
+
+  it("allows forceResurrect recreation and clears allowResurrection", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ title: "a", description: "alpha", column: "todo" });
+    await store.deleteTask(task.id, { allowResurrection: true });
+
+    const created: string[] = [];
+    store.on("task:created", (event) => created.push(event.id));
+    const recreated = await store.createTaskWithReservedId(
+      { title: "c", description: "charlie", forceResurrect: true, column: "todo" },
+      { taskId: task.id },
+    );
+    expect(recreated.id).toBe(task.id);
+    expect(created).toEqual([task.id]);
+
+    const row = (store as any).db.prepare("SELECT deletedAt, allowResurrection FROM tasks WHERE id = ?").get(task.id) as {
+      deletedAt: string | null;
+      allowResurrection: number;
+    };
+    expect(row.deletedAt).toBeNull();
+    expect(row.allowResurrection).toBe(0);
+  });
+
+  it("allows recreation when tombstone row has allowResurrection=1", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ title: "a", description: "alpha", column: "todo" });
+    await store.deleteTask(task.id, { allowResurrection: true });
+
+    const recreated = await store.createTaskWithReservedId({ title: "d", description: "delta", column: "todo" }, { taskId: task.id });
+    expect(recreated.id).toBe(task.id);
+    const row = (store as any).db.prepare("SELECT deletedAt, allowResurrection FROM tasks WHERE id = ?").get(task.id) as {
+      deletedAt: string | null;
+      allowResurrection: number;
+    };
+    expect(row.deletedAt).toBeNull();
+    expect(row.allowResurrection).toBe(0);
+  });
+
+  it("records task:resurrection-blocked audit for createTask refusal", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ title: "a", description: "alpha", column: "todo" });
+    await store.deleteTask(task.id);
+
+    await expect(
+      store.createTaskWithReservedId({ title: "b", description: "beta", column: "todo" }, { taskId: task.id }),
+    ).rejects.toBeInstanceOf(TombstonedTaskResurrectionError);
+
+    const events = (store as any).db.prepare(
+      "SELECT mutationType, metadata FROM runAuditEvents WHERE taskId = ? AND mutationType = ?"
+    ).all(task.id, "task:resurrection-blocked") as Array<{ mutationType: string; metadata: string | null }>;
+    expect(events.length).toBeGreaterThan(0);
+    expect(events.at(-1)?.metadata ?? "").toContain("createTask");
+  });
+});
--- a/packages/core/src/db.ts
+++ b/packages/core/src/db.ts
@@ -314,7 +314,8 @@ CREATE TABLE IF NOT EXISTS tasks (
  checkoutRunId TEXT,
  checkoutLeaseRenewedAt TEXT,
  checkoutLeaseEpoch INTEGER DEFAULT 0,
-  deletedAt TEXT
+  deletedAt TEXT,
+  allowResurrection INTEGER DEFAULT 0
 );

 -- Config table (single row with project settings)
@@ -3505,6 +3506,7 @@ export class Database {

    if (version < 88) {
      this.applyMigration(88, () => {
+        this.addColumnIfMissing("tasks", "allowResurrection", "INTEGER DEFAULT 0");
        try {
          const taskColumns = this.getTableColumns("tasks");
          const requiredColumns = ["paused", "userPaused", "pausedByAgentId", "pausedReason"];
--- a/packages/core/src/duplicate-intake.ts
+++ b/packages/core/src/duplicate-intake.ts
@@ -21,11 +21,17 @@ export interface SameAgentDuplicateCandidate {
  createdAt: number;
  sourceAgentId: string | null;
  sourceParentTaskId?: string | null;
+  tombstoned?: boolean;
+  deletedAt?: string;
+  allowResurrection?: boolean;
 }

 export interface SameAgentDuplicateMatch {
  id: string;
  score: number;
+  tombstoned?: boolean;
+  deletedAt?: string;
+  allowResurrection?: boolean;
 }

 /**
@@ -51,10 +57,11 @@ export function findSameAgentDuplicates(
  const inputParentId = input.sourceParentTaskId ?? null;

  const recent = candidates.filter((candidate) => {
-    if (candidate.createdAt < cutoff) return false;
    const agentMatch = inputAgentId != null && candidate.sourceAgentId === inputAgentId;
    const parentMatch = inputParentId != null && candidate.sourceParentTaskId === inputParentId;
-    return agentMatch || parentMatch;
+    if (!agentMatch && !parentMatch) return false;
+    if (candidate.tombstoned) return true;
+    return candidate.createdAt >= cutoff;
  });

  const matches = findDuplicateMatches(
@@ -68,7 +75,17 @@ export function findSameAgentDuplicates(
    { threshold },
  );

-  return matches.map((match) => ({ id: match.id, score: match.score }));
+  const metadataById = new Map(recent.map((candidate) => [candidate.id, candidate]));
+  return matches.map((match) => {
+    const candidate = metadataById.get(match.id);
+    return {
+      id: match.id,
+      score: match.score,
+      tombstoned: candidate?.tombstoned,
+      deletedAt: candidate?.deletedAt,
+      allowResurrection: candidate?.allowResurrection,
+    };
+  });
 }

 export async function archiveAsSameAgentDuplicate(
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -134,6 +134,7 @@ export {
  SelfDefeatingDependencyError,
  DependencyCycleError,
  TaskDeletedError,
+  TombstonedTaskResurrectionError,
  MergeQueueTaskNotFoundError,
  MergeQueueInvalidColumnError,
  MergeQueueLeaseOwnershipError,
--- a/packages/core/src/settings-schema.ts
+++ b/packages/core/src/settings-schema.ts
@@ -188,6 +188,7 @@ export const DEFAULT_PROJECT_SETTINGS = {
  pollIntervalMs: 15000,
  heartbeatMultiplier: 1,
  autoClaimCandidatesInPrompt: 5,
+  tombstoneStickyWindowDays: 7,
  heartbeatScopeDiscipline: "strict",
  heartbeatPromptTemplate: "default",
  groupOverlappingFiles: true,
--- a/packages/core/src/store.ts
+++ b/packages/core/src/store.ts
@@ -173,6 +173,7 @@ interface TaskRow {
  checkoutLeaseRenewedAt: string | null;
  checkoutLeaseEpoch: number | null;
  deletedAt: string | null;
+  allowResurrection: number | null;
 }

 /** Database row shape for the task_documents table. */
@@ -621,6 +622,20 @@ export class TaskDeletedError extends Error {
  }
 }

+export class TombstonedTaskResurrectionError extends Error {
+  constructor(
+    public readonly taskId: string,
+    public readonly deletedAt: string,
+    public readonly allowResurrection: boolean,
+  ) {
+    super(
+      `Task ${taskId} is soft-deleted (deletedAt=${deletedAt}) and cannot be recreated without forceResurrect: true. `
+      + `Operator unlock: allowResurrection=${allowResurrection}`,
+    );
+    this.name = "TombstonedTaskResurrectionError";
+  }
+}
+
 export class TaskHasLineageChildrenError extends Error {
  readonly taskId: string;
  readonly childIds: string[];
@@ -1499,6 +1514,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
      checkoutLeaseRenewedAt: row.checkoutLeaseRenewedAt || undefined,
      checkoutLeaseEpoch: row.checkoutLeaseEpoch ?? undefined,
      deletedAt: row.deletedAt ?? undefined,
+      allowResurrection: row.allowResurrection ? true : undefined,
    };
  }

@@ -1740,7 +1756,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
      "breakIntoSubtasks", "noCommitsExpected", "enabledWorkflowSteps", "modifiedFiles",
      "missionId", "sliceId", "scopeOverride", "scopeOverrideReason", "scopeAutoWiden", "assignedAgentId", "pausedByAgentId", "assigneeUserId", "nodeId", "effectiveNodeId", "effectiveNodeSource",
      "sourceType", "sourceAgentId", "sourceRunId", "sourceSessionId", "sourceMessageId", "sourceParentTaskId", "sourceMetadata",
-      "checkedOutBy", "checkedOutAt", "checkoutNodeId", "checkoutRunId", "checkoutLeaseRenewedAt", "checkoutLeaseEpoch", "deletedAt",
+      "checkedOutBy", "checkedOutAt", "checkoutNodeId", "checkoutRunId", "checkoutLeaseRenewedAt", "checkoutLeaseEpoch", "deletedAt", "allowResurrection",
      // `log` is fetched in slim mode so the server can aggregate
      // `timedExecutionMs` from `[timing] … in <N>ms` entries before
      // returning. The log itself is stripped from the response —
@@ -1789,7 +1805,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
      "breakIntoSubtasks", "noCommitsExpected", "enabledWorkflowSteps", "modifiedFiles",
      "missionId", "sliceId", "scopeOverride", "scopeOverrideReason", "scopeAutoWiden", "assignedAgentId", "pausedByAgentId", "assigneeUserId", "nodeId", "effectiveNodeId", "effectiveNodeSource",
      "sourceType", "sourceAgentId", "sourceRunId", "sourceSessionId", "sourceMessageId", "sourceParentTaskId", "sourceMetadata",
-      "checkedOutBy", "checkedOutAt", "checkoutNodeId", "checkoutRunId", "checkoutLeaseRenewedAt", "checkoutLeaseEpoch", "deletedAt",
+      "checkedOutBy", "checkedOutAt", "checkoutNodeId", "checkoutRunId", "checkoutLeaseRenewedAt", "checkoutLeaseEpoch", "deletedAt", "allowResurrection",
    ];

    const limitedLog = `
@@ -1926,6 +1942,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
      task.checkoutLeaseRenewedAt ?? null,
      task.checkoutLeaseEpoch ?? 0,
      task.deletedAt ?? null,
+      task.allowResurrection ? 1 : 0,
    ];
  }

@@ -1948,7 +1965,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
        dependencies, steps, log, attachments, steeringComments,
        comments, review, reviewState, workflowStepResults, prInfo, prInfos, issueInfo, githubTracking,
        sourceIssueProvider, sourceIssueRepository, sourceIssueExternalIssueId, sourceIssueNumber, sourceIssueUrl,
-        mergeDetails, breakIntoSubtasks, noCommitsExpected, enabledWorkflowSteps, modifiedFiles, missionId, sliceId, scopeOverride, scopeOverrideReason, scopeAutoWiden, assignedAgentId, pausedByAgentId, assigneeUserId, nodeId, effectiveNodeId, effectiveNodeSource, sourceType, sourceAgentId, sourceRunId, sourceSessionId, sourceMessageId, sourceParentTaskId, sourceMetadata, checkedOutBy, checkedOutAt, checkoutNodeId, checkoutRunId, checkoutLeaseRenewedAt, checkoutLeaseEpoch, deletedAt
+        mergeDetails, breakIntoSubtasks, noCommitsExpected, enabledWorkflowSteps, modifiedFiles, missionId, sliceId, scopeOverride, scopeOverrideReason, scopeAutoWiden, assignedAgentId, pausedByAgentId, assigneeUserId, nodeId, effectiveNodeId, effectiveNodeSource, sourceType, sourceAgentId, sourceRunId, sourceSessionId, sourceMessageId, sourceParentTaskId, sourceMetadata, checkedOutBy, checkedOutAt, checkoutNodeId, checkoutRunId, checkoutLeaseRenewedAt, checkoutLeaseEpoch, deletedAt, allowResurrection
      ) VALUES (${placeholders})
    `).run(...values);
    this.db.bumpLastModified();
@@ -1975,7 +1992,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
        dependencies, steps, log, attachments, steeringComments,
        comments, review, reviewState, workflowStepResults, prInfo, prInfos, issueInfo, githubTracking,
        sourceIssueProvider, sourceIssueRepository, sourceIssueExternalIssueId, sourceIssueNumber, sourceIssueUrl,
-        mergeDetails, breakIntoSubtasks, noCommitsExpected, enabledWorkflowSteps, modifiedFiles, missionId, sliceId, scopeOverride, scopeOverrideReason, scopeAutoWiden, assignedAgentId, pausedByAgentId, assigneeUserId, nodeId, effectiveNodeId, effectiveNodeSource, sourceType, sourceAgentId, sourceRunId, sourceSessionId, sourceMessageId, sourceParentTaskId, sourceMetadata, checkedOutBy, checkedOutAt, checkoutNodeId, checkoutRunId, checkoutLeaseRenewedAt, checkoutLeaseEpoch, deletedAt
+        mergeDetails, breakIntoSubtasks, noCommitsExpected, enabledWorkflowSteps, modifiedFiles, missionId, sliceId, scopeOverride, scopeOverrideReason, scopeAutoWiden, assignedAgentId, pausedByAgentId, assigneeUserId, nodeId, effectiveNodeId, effectiveNodeSource, sourceType, sourceAgentId, sourceRunId, sourceSessionId, sourceMessageId, sourceParentTaskId, sourceMetadata, checkedOutBy, checkedOutAt, checkoutNodeId, checkoutRunId, checkoutLeaseRenewedAt, checkoutLeaseEpoch, deletedAt, allowResurrection
      ) VALUES (${placeholders})
      ON CONFLICT(id) DO UPDATE SET
        lineageId = excluded.lineageId,
@@ -2086,7 +2103,8 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
        checkoutRunId = excluded.checkoutRunId,
        checkoutLeaseRenewedAt = excluded.checkoutLeaseRenewedAt,
        checkoutLeaseEpoch = excluded.checkoutLeaseEpoch,
-        deletedAt = excluded.deletedAt
+        deletedAt = excluded.deletedAt,
+        allowResurrection = excluded.allowResurrection
    `).run(...this.getTaskPersistValues(task));
    this.db.bumpLastModified();
  }
@@ -2211,6 +2229,38 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
    }
  }

+  private maybeResolveTombstonedTaskId(
+    id: string,
+    input: Pick<TaskCreateInput, "forceResurrect">,
+    operation: "createTask" | "duplicateTask" | "refineTask",
+  ): void {
+    const existing = this.readTaskFromDb(id, { includeDeleted: true });
+    if (!existing?.deletedAt) return;
+
+    const allowResurrection = existing.allowResurrection === true;
+    if (input.forceResurrect === true || allowResurrection) {
+      this.db.prepare("DELETE FROM tasks WHERE id = ?").run(id);
+      this.db.bumpLastModified();
+      return;
+    }
+
+    storeLog.warn(`[tombstone-resurrection-blocked] ${id} deletedAt=${existing.deletedAt}`);
+    this.insertRunAuditEventRow({
+      taskId: id,
+      domain: "database",
+      mutationType: "task:resurrection-blocked",
+      target: id,
+      metadata: {
+        id,
+        deletedAt: existing.deletedAt,
+        allowResurrection,
+        operation,
+      },
+    });
+
+    throw new TombstonedTaskResurrectionError(id, existing.deletedAt, allowResurrection);
+  }
+
  private isTaskArchived(id: string): boolean {
    const row = this.db.prepare(`SELECT "column" FROM tasks WHERE id = ? AND ${TaskStore.ACTIVE_TASKS_WHERE}`).get(id) as { column: Column } | undefined;
    if (row) {
@@ -3524,6 +3574,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {

    await this.assertNoDependencyCycle(id, input.dependencies ?? [], "createTaskWithReservedId");

+    this.maybeResolveTombstonedTaskId(id, input, "createTask");
    this.assertTaskIdAvailable(id);

    const title = input.title?.trim() || undefined;
@@ -3678,6 +3729,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
      storeLog.log(`[title-id-drift] normalized title for ${id}: removed=[${removed.join(",")}]`);
    }

+    this.maybeResolveTombstonedTaskId(id, input, "createTask");
    this.assertTaskIdAvailable(id);

    const dir = this.taskDir(id);
@@ -3730,31 +3782,107 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
        return agentMatch || parentMatch;
      });

+      const settings = await this.getSettings();
+      const stickyWindowDays = Math.max(0, settings.tombstoneStickyWindowDays ?? 7);
+      let tombstonedCandidates: Array<{
+        id: string;
+        title: string | null;
+        description: string;
+        column: Column;
+        createdAt: string;
+        sourceAgentId: string | null;
+        deletedAt: string;
+        allowResurrection: number | null;
+      }> = [];
+
+      if (stickyWindowDays > 0) {
+        try {
+          const cutoffIso = new Date(nowMs - stickyWindowDays * 24 * 60 * 60 * 1000).toISOString();
+          tombstonedCandidates = this.db.prepare(`
+            SELECT id, title, description, "column", createdAt, sourceAgentId, deletedAt, allowResurrection
+              FROM tasks
+             WHERE deletedAt IS NOT NULL
+               AND deletedAt >= ?
+               AND sourceAgentId = ?
+               AND id != ?
+          `).all(cutoffIso, sourceAgentId, task.id) as typeof tombstonedCandidates;
+        } catch (error) {
+          storeLog.warn(`FN-5233 tombstone candidate widening failed open for ${task.id}: ${getErrorMessage(error)}`);
+        }
+      }
+
      const matches = findSameAgentDuplicates(
        {
          title: input.title ?? task.title,
          description: input.description,
          sourceParentTaskId,
        },
-        recent.map((candidate) => ({
-          id: candidate.id,
-          title: candidate.title ?? "",
-          description: candidate.description,
-          column: candidate.column,
-          createdAt: Date.parse(candidate.createdAt),
-          sourceAgentId: candidate.sourceAgentId ?? null,
-          sourceParentTaskId: candidate.sourceParentTaskId ?? null,
-        })),
+        [
+          ...recent.map((candidate) => ({
+            id: candidate.id,
+            title: candidate.title ?? "",
+            description: candidate.description,
+            column: candidate.column,
+            createdAt: Date.parse(candidate.createdAt),
+            sourceAgentId: candidate.sourceAgentId ?? null,
+            sourceParentTaskId: candidate.sourceParentTaskId ?? null,
+            tombstoned: false,
+          })),
+          ...tombstonedCandidates.map((candidate) => ({
+            id: candidate.id,
+            title: candidate.title ?? "",
+            description: candidate.description,
+            column: "todo" as Column,
+            createdAt: Date.parse(candidate.createdAt),
+            sourceAgentId: candidate.sourceAgentId,
+            sourceParentTaskId: null,
+            tombstoned: true,
+            deletedAt: candidate.deletedAt,
+            allowResurrection: candidate.allowResurrection === 1,
+          })),
+        ],
        { nowMs, sourceAgentId },
      );

      if (matches.length === 0) return;

-      const siblingTaskIds = matches.map((match) => match.id);
-      const scores = Object.fromEntries(matches.map((match) => [match.id, match.score]));
+      const tombstonedMatch = matches.find((match) => match.tombstoned && match.allowResurrection !== true);
+      if (tombstonedMatch?.deletedAt) {
+        this.insertRunAuditEventRow({
+          taskId: task.id,
+          domain: "database",
+          mutationType: "intake:resurrection-blocked",
+          target: task.id,
+          metadata: {
+            matchedTaskId: tombstonedMatch.id,
+            score: tombstonedMatch.score,
+            tombstoneDeletedAt: tombstonedMatch.deletedAt,
+            stickyWindowDays,
+          },
+        });
+        if (this.isWatching) this.taskCache.delete(task.id);
+        this.deleteTaskById(task.id);
+        const { rm } = await import("node:fs/promises");
+        const taskDir = this.taskDir(task.id);
+        if (existsSync(taskDir)) {
+          await rm(taskDir, { recursive: true, force: true });
+        }
+        throw new TombstonedTaskResurrectionError(
+          tombstonedMatch.id,
+          tombstonedMatch.deletedAt,
+          tombstonedMatch.allowResurrection === true,
+        );
+      }
+
+      const siblingTaskIds = matches.filter((match) => !match.tombstoned).map((match) => match.id);
+      if (siblingTaskIds.length === 0) return;
+      const scores = Object.fromEntries(matches.filter((match) => !match.tombstoned).map((match) => [match.id, match.score]));
      await archiveAsSameAgentDuplicate(this, task.id, siblingTaskIds, scores);
      task.column = "archived";
    } catch (error) {
+      if (error instanceof TombstonedTaskResurrectionError) {
+        throw error;
+      }
      storeLog.warn(`FN-4892 same-agent duplicate intake failed open for ${task.id}: ${getErrorMessage(error)}`);
    }
  }
@@ -3806,6 +3934,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
          baseBranch: sourceTask.baseBranch,
        };

+        this.maybeResolveTombstonedTaskId(newId, {}, "duplicateTask");
        this.assertTaskIdAvailable(newId);

        const newDir = this.taskDir(newId);
@@ -3882,6 +4011,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
          attachments: sourceTask.attachments ? [...sourceTask.attachments] : undefined,
        };

+        this.maybeResolveTombstonedTaskId(newId, {}, "refineTask");
        this.assertTaskIdAvailable(newId);

        const newDir = this.taskDir(newId);
@@ -6620,6 +6750,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
    options?: {
      removeDependencyReferences?: boolean;
      removeLineageReferences?: boolean;
+      allowResurrection?: boolean;
      githubIssueAction?: GithubIssueAction;
      auditContext?: { agentId: string; runId: string; sessionId?: string };
    },
@@ -6667,7 +6798,8 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
        rewrittenDependents = this.rewriteDependentsForRemoval(id, dependentIds);
        rewrittenLineageChildren = this.rewriteLineageChildrenForRemoval(id, lineageChildIds);
        const deletedAt = new Date().toISOString();
-        this.db.prepare("UPDATE tasks SET \"column\" = 'archived', deletedAt = ?, updatedAt = ? WHERE id = ?").run(deletedAt, deletedAt, id);
+        const allowResurrection = options?.allowResurrection === true ? 1 : 0;
+        this.db.prepare("UPDATE tasks SET \"column\" = 'archived', deletedAt = ?, allowResurrection = ?, updatedAt = ? WHERE id = ?").run(deletedAt, allowResurrection, deletedAt, id);
        this.recordRunAuditEvent({
          domain: "database",
          mutationType: "task:deleted",
@@ -6681,6 +6813,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
            githubIssueAction: options?.githubIssueAction ?? "auto",
            removeDependencyReferences: !!options?.removeDependencyReferences,
            removeLineageReferences: !!options?.removeLineageReferences,
+            allowResurrection: options?.allowResurrection === true,
            sessionId: options?.auditContext?.sessionId,
          },
        });
--- a/packages/core/src/types.ts
+++ b/packages/core/src/types.ts
@@ -1879,6 +1879,7 @@ export interface Task {
   *  todo/triage when resume state is not preserved. */
  executionCompletedAt?: string;
  deletedAt?: string;
+  allowResurrection?: boolean;
  createdAt: string;
  updatedAt: string;
 }
@@ -1915,6 +1916,11 @@ export interface TaskCreateInput {
  title?: string;
  /** Optional lineage override for trusted replication/import paths only. */
  lineageId?: string;
+  /**
+   * Opt-in createTask override for soft-deleted ID reuse.
+   * Not persisted to storage.
+   */
+  forceResurrect?: boolean;
  description: string;
  /** Configured merge target/base branch for this task (task intent).
   *  Defaults to the project default branch when omitted. */
@@ -2701,6 +2707,9 @@ export interface ProjectSettings {
  heartbeatMultiplier?: number;
  /** Number of auto-claim candidates rendered in no-task heartbeat prompts. Range: 0-10. Default: 5. */
  autoClaimCandidatesInPrompt?: number;
+  /** Sticky window for intake duplicate checks against soft-deleted tasks.
+   * Unit: days. Default: 7. Set to 0 to disable tombstone-window widening. */
+  tombstoneStickyWindowDays?: number;
  /** Heartbeat scope-discipline procedure mode.
   * - "strict": coordination-focused scope discipline (default)
   * - "lite": pre-FN-3884 behavior
--- a/packages/dashboard/src/tests/routes-tasks-ops.test.ts
+++ b/packages/dashboard/src/tests/routes-tasks-ops.test.ts
@@ -1158,6 +1158,7 @@ describe("DELETE /tasks/:id", () => {
    expect(res.status).toBe(200);
    expect(res.body.id).toBe("KB-001");
    expect(store.deleteTask).toHaveBeenCalledWith("KB-001", expect.objectContaining({
+      allowResurrection: false,
      removeDependencyReferences: false,
      removeLineageReferences: false,
      githubIssueAction: undefined,
@@ -1223,6 +1224,20 @@ describe("DELETE /tasks/:id", () => {
    }));
  });

+  it("passes allowResurrection when explicitly requested", async () => {
+    const deletedTask = { ...FAKE_TASK_DETAIL, id: "KB-001" };
+    (store.deleteTask as ReturnType<typeof vi.fn>).mockResolvedValue(deletedTask);
+
+    const res = await REQUEST(buildApp(), "DELETE", "/api/tasks/KB-001?allowResurrection=true");
+
+    expect(res.status).toBe(200);
+    expect(store.deleteTask).toHaveBeenCalledWith("KB-001", expect.objectContaining({
+      allowResurrection: true,
+      removeDependencyReferences: false,
+      removeLineageReferences: false,
+    }));
+  });
+
  it.each(["close", "delete", "leave", "auto"] as const)("forwards githubIssueAction=%s", async (githubIssueAction) => {
    const deletedTask = { ...FAKE_TASK_DETAIL, id: "KB-001" };
    (store.deleteTask as ReturnType<typeof vi.fn>).mockResolvedValue(deletedTask);
--- a/packages/dashboard/src/routes/register-task-workflow-routes.ts
+++ b/packages/dashboard/src/routes/register-task-workflow-routes.ts
@@ -3415,6 +3415,8 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
      const removeLineageReferences = req.query.removeLineageReferences === "1"
        || req.query.removeLineageReferences === "true";
      const githubIssueActionRaw = req.query.githubIssueAction;
+      const allowResurrection = req.query.allowResurrection === "1"
+        || req.query.allowResurrection === "true";
      const githubIssueActionValues: readonly GithubIssueAction[] = ["close", "delete", "leave", "auto"];
      let githubIssueAction: GithubIssueAction | undefined;
      if (typeof githubIssueActionRaw === "string") {
@@ -3426,6 +3428,7 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
      const task = await scopedStore.deleteTask(req.params.id, {
        removeDependencyReferences,
        removeLineageReferences,
+        allowResurrection,
        githubIssueAction,
        auditContext: {
          agentId: "system",
--- a/packages/engine/src/tests/reliability-interactions/soft-delete-stickiness-FN-5233.test.ts
+++ b/packages/engine/src/tests/reliability-interactions/soft-delete-stickiness-FN-5233.test.ts
@@ -0,0 +1,82 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { mkdtemp, mkdir, rm } from "node:fs/promises";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+
+import { TaskDeletedError, TaskStore, TombstonedTaskResurrectionError } from "@fusion/core";
+
+describe("reliability interactions: FN-5233 soft-delete stickiness", () => {
+  let rootDir: string;
+  let store: TaskStore;
+
+  beforeEach(async () => {
+    rootDir = await mkdtemp(join(tmpdir(), "fn-5233-reliability-"));
+    await mkdir(join(rootDir, ".fusion"), { recursive: true });
+    store = new TaskStore(rootDir, undefined, { inMemoryDb: false });
+    await store.init();
+  });
+
+  afterEach(async () => {
+    vi.useRealTimers();
+    await rm(rootDir, { recursive: true, force: true });
+  });
+
+  it("composes Layer1 delete signal + Layer2 write guard + Layer3 recreate refusal", async () => {
+    const task = await store.createTask({ title: "target", description: "target", column: "todo" });
+    const deletedEvents: string[] = [];
+    store.on("task:deleted", (event) => deletedEvents.push(event.id));
+
+    await store.deleteTask(task.id);
+    expect(deletedEvents).toEqual([task.id]);
+
+    await expect(store.updateTask(task.id, { title: "stale write" })).rejects.toBeInstanceOf(TaskDeletedError);
+    await expect(
+      store.createTaskWithReservedId({ title: "recreate", description: "same", column: "todo" }, { taskId: task.id }),
+    ).rejects.toBeInstanceOf(TombstonedTaskResurrectionError);
+  });
+
+  it("refuses near-duplicate intake against recent tombstone and supports explicit unlock", async () => {
+    await store.updateSettings({ tombstoneStickyWindowDays: 7 });
+    const original = await store.createTask({
+      title: "duplicate me",
+      description: "duplicate me now",
+      source: { sourceType: "unknown", sourceAgentId: "agent-r1" },
+    });
+    await store.deleteTask(original.id);
+
+    await expect(store.createTask({
+      title: "duplicate me",
+      description: "duplicate me now",
+      source: { sourceType: "unknown", sourceAgentId: "agent-r1" },
+    })).rejects.toBeInstanceOf(TombstonedTaskResurrectionError);
+
+    const blocked = (store as any).db.prepare("SELECT mutationType FROM runAuditEvents WHERE mutationType = 'intake:resurrection-blocked'").all() as Array<{ mutationType: string }>;
+    expect(blocked.length).toBeGreaterThan(0);
+
+    const unlocked = await store.createTask({
+      title: "unlock target",
+      description: "unlock target",
+      source: { sourceType: "unknown", sourceAgentId: "agent-r2" },
+    });
+    await store.deleteTask(unlocked.id, { allowResurrection: true });
+    await expect(store.createTaskWithReservedId({ title: "allowed", description: "allowed", column: "todo" }, { taskId: unlocked.id })).resolves.toMatchObject({ id: unlocked.id });
+  });
+
+  it("does not emit recreated task ids across repeated stale attempts over simulated 6 minutes", async () => {
+    vi.useFakeTimers();
+    const task = await store.createTask({ title: "clock", description: "clock", column: "todo" });
+    await store.deleteTask(task.id);
+
+    const createdEvents: string[] = [];
+    store.on("task:created", (event) => createdEvents.push(event.id));
+
+    for (let i = 0; i < 6; i += 1) {
+      vi.advanceTimersByTime(60_000);
+      await expect(
+        store.createTaskWithReservedId({ title: `retry-${i}`, description: "retry", column: "todo" }, { taskId: task.id }),
+      ).rejects.toBeInstanceOf(TombstonedTaskResurrectionError);
+    }
+
+    expect(createdEvents).toEqual([]);
+  });
+});