feat(FN-4899): complete Step 4 — surface duplicate lineage in CLI outputs

Fusion-Task-Id: FN-4899
Fusion-Task-Lineage: 2ae24667-6635-4268-a620-d6012266d8f2

packages/cli/src/__tests__/extension.test.ts

@@ -854,22 +854,10 @@ describe.skipIf(!SHOULD_RUN_LEGACY_EXTENSION_INTEGRATION)("fn pi extension (lega
   describe("fn_task_show", () => {
     it("shows task details", async () => {
       const createTool = api.tools.get("fn_task_create")!;
-      await createTool.execute(
-        "c1",
-        { description: "Implement caching layer" },
-        undefined,
-        undefined,
-        makeCtx(tmpDir),
-      );
+      await createTool.execute("c1", { description: "Implement caching layer" }, undefined, undefined, makeCtx(tmpDir));
 
       const showTool = api.tools.get("fn_task_show")!;
-      const result = await showTool.execute(
-        "call-1",
-        { id: "FN-001" },
-        undefined,
-        undefined,
-        makeCtx(tmpDir),
-      );
+      const result = await showTool.execute("call-1", { id: "FN-001" }, undefined, undefined, makeCtx(tmpDir));
 
       expect(result.content[0].text).toContain("FN-001");
       expect(result.content[0].text).toContain("Implement caching layer");
@@ -891,10 +879,7 @@ describe.skipIf(!SHOULD_RUN_LEGACY_EXTENSION_INTEGRATION)("fn pi extension (lega
           sourceMetadata: { agentName: "Scout" },
         },
       });
-      await store.createTask({
-        description: "UI created",
-        source: { sourceType: "dashboard_ui" },
-      });
+      await store.createTask({ description: "UI created", source: { sourceType: "dashboard_ui" } });
 
       const showTool = api.tools.get("fn_task_show")!;
       const agentResult = await showTool.execute("call-2", { id: "FN-001" }, undefined, undefined, makeCtx(tmpDir));
@@ -902,8 +887,23 @@ describe.skipIf(!SHOULD_RUN_LEGACY_EXTENSION_INTEGRATION)("fn pi extension (lega
 
       expect(agentResult.content[0].text).toContain("Created via: Agent (Scout)");
       expect(dashboardResult.content[0].text).toContain("Created via: Dashboard");
-      expect(agentResult.details.task.sourceMetadata?.agentName).toBe("Scout");
-      expect(agentResult.details.task.sourceAgentId).toBe("agent-999");
+    });
+
+    it("shows duplicate lineage with archived annotation", async () => {
+      const store = new TaskStore(tmpDir);
+      await store.init();
+
+      const archivedSource = await store.createTask({ description: "Archived source" });
+      await store.moveTask(archivedSource.id, "done");
+      await store.archiveTask(archivedSource.id);
+      await store.createTask({
+        description: "Dup task",
+        source: { sourceType: "chat_session", sourceMetadata: { duplicateOfTaskIds: [archivedSource.id, "FN-404"] } },
+      });
+
+      const showTool = api.tools.get("fn_task_show")!;
+      const result = await showTool.execute("call-4", { id: "FN-002" }, undefined, undefined, makeCtx(tmpDir));
+      expect(result.content[0].text).toContain(`Duplicate of: ${archivedSource.id} (archived), FN-404`);
     });
   });
 

packages/cli/src/commands/__tests__/task.test.ts

@@ -42,6 +42,17 @@ vi.mock("@fusion/core", () => {
     TaskStore: vi.fn(),
     COLUMNS,
     COLUMN_LABELS,
+    getTaskDuplicateLineage: vi.fn((task: { sourceType?: string; sourceParentTaskId?: string; sourceMetadata?: any }) => {
+      const ids: string[] = [];
+      if (task.sourceType === "task_duplicate" && task.sourceParentTaskId) ids.push(task.sourceParentTaskId);
+      const metadata = task.sourceMetadata?.duplicateOfTaskIds;
+      if (Array.isArray(metadata)) {
+        for (const id of metadata) {
+          if (typeof id === "string" && !ids.includes(id)) ids.push(id);
+        }
+      }
+      return ids;
+    }),
     CentralCore: vi.fn().mockImplementation(function() {
       return {
         init: vi.fn().mockResolvedValue(undefined),
@@ -219,6 +230,28 @@ describe("runTaskShow", () => {
     const output = logSpy.mock.calls.map((call) => String(call[0])).join("\n");
     expect(output).not.toContain("Source:");
   });
+
+  it("prints duplicate lineage from metadata and task_duplicate parent", async () => {
+    mockTaskStoreGetTask(makeTask({
+      sourceType: "task_duplicate",
+      sourceParentTaskId: "FN-2905",
+      sourceMetadata: { duplicateOfTaskIds: ["FN-9"] },
+    }));
+
+    await runTaskShow("FN-001");
+
+    const output = logSpy.mock.calls.map((call) => String(call[0])).join("\n");
+    expect(output).toContain("Duplicate of: FN-2905, FN-9");
+  });
+
+  it("prints duplicate lineage from metadata list", async () => {
+    mockTaskStoreGetTask(makeTask({ sourceMetadata: { duplicateOfTaskIds: ["FN-1", "FN-2"] } }));
+
+    await runTaskShow("FN-001");
+
+    const output = logSpy.mock.calls.map((call) => String(call[0])).join("\n");
+    expect(output).toContain("Duplicate of: FN-1, FN-2");
+  });
 });
 
 describe("task node overrides", () => {

packages/cli/src/commands/task.ts

@@ -1,6 +1,6 @@
 import { exec } from "node:child_process";
 import { promisify } from "node:util";
-import { TaskStore, COLUMNS, COLUMN_LABELS, CentralCore, type Settings, type Column, type StepStatus, type AgentLogType, type AgentLogEntry } from "@fusion/core";
+import { TaskStore, COLUMNS, COLUMN_LABELS, CentralCore, getTaskDuplicateLineage, type Settings, type Column, type StepStatus, type AgentLogType, type AgentLogEntry } from "@fusion/core";
 import { aiMergeTask, listBranchRecoveryCandidates, type BranchRecoveryCandidate } from "@fusion/engine";
 import { createInterface } from "node:readline/promises";
 import type { PlanningQuestion, PlanningSummary } from "@fusion/core";
@@ -59,6 +59,22 @@ function getResearchSourceContext(sourceMetadata: unknown): string | undefined {
   return typeof runId === "string" && runId.length > 0 ? runId : undefined;
 }
 
+async function formatTaskDuplicateLineage(task: Awaited<ReturnType<TaskStore["getTask"]>>, store: TaskStore): Promise<string | null> {
+  const lineage = getTaskDuplicateLineage(task);
+  if (lineage.length === 0) return null;
+
+  const labels = await Promise.all(lineage.map(async (id) => {
+    try {
+      const linked = await store.getTask(id);
+      return linked.column === "archived" ? `${id} (archived)` : id;
+    } catch {
+      return id;
+    }
+  }));
+
+  return labels.join(", ");
+}
+
 function formatTaskSource(task: {
   sourceType?: string;
   sourceAgentId?: string;
@@ -677,6 +693,10 @@ export async function runTaskShow(id: string, projectName?: string) {
   if (sourceSummary) {
     console.log(`  Source: ${sourceSummary}`);
   }
+  const duplicateLineage = await formatTaskDuplicateLineage(task, store);
+  if (duplicateLineage) {
+    console.log(`  Duplicate of: ${duplicateLineage}`);
+  }
   console.log();
 
   // Steps

packages/cli/src/extension.ts

@@ -19,6 +19,7 @@ import {
   resolveResearchSettings,
   canAgentTakeImplementationTaskForExplicitRouting,
   formatRoleMismatchReason,
+  getTaskDuplicateLineage,
   resolveAgentProvisioningPolicy,
   TASK_PRIORITIES,
   resolveSecretAccessPolicy,
@@ -269,6 +270,22 @@ function getTaskSourceLabel(task: Pick<Task, "sourceType" | "sourceMetadata" | "
   }
 }
 
+async function formatDuplicateLineageLine(task: Task, store: TaskStore): Promise<string | null> {
+  const lineage = getTaskDuplicateLineage(task);
+  if (lineage.length === 0) return null;
+
+  const labels = await Promise.all(lineage.map(async (id) => {
+    try {
+      const linked = await store.getTask(id);
+      return linked.column === "archived" ? `${id} (archived)` : id;
+    } catch {
+      return id;
+    }
+  }));
+
+  return `Duplicate of: ${labels.join(", ")}`;
+}
+
 function formatTaskLine(t: Task): string {
   const label =
     t.title || t.description.slice(0, 60) + (t.description.length > 60 ? "…" : "");
@@ -755,6 +772,10 @@ export default function kbExtension(pi: ExtensionAPI) {
       if (sourceLabel) {
         lines.push(`Created via: ${sourceLabel}`);
       }
+      const duplicateLineage = await formatDuplicateLineageLine(task, store);
+      if (duplicateLineage) {
+        lines.push(duplicateLineage);
+      }
       if (task.paused) lines.push("Status: PAUSED");
       lines.push("");