fix(FN-2107): normalize task ID handling for task creation tools

- Return the created task ID directly from runTaskPlan and propagate it through fn_task_plan
- Remove hardcoded FN-### log parsing so CLI extension supports structured IDs like PROJ-042
- Add heartbeat fallback parsing from task_create text output when details.taskId is absent
- Expand engine and CLI tests to cover structured task IDs and updated task-plan return behavior

packages/engine/src/agent-heartbeat.test.ts

@@ -9,6 +9,7 @@ import {
   HEARTBEAT_SYSTEM_PROMPT_NO_TASK,
 } from "./agent-heartbeat.js";
 import { AgentLogger } from "./agent-logger.js";
+import * as agentTools from "./agent-tools.js";
 import type { AgentStore, AgentHeartbeatRun, TaskStore, TaskDetail, Agent, MessageStore, Message, AgentBudgetStatus } from "@fusion/core";
 
 // Mock logger to suppress noise in test output
@@ -3290,6 +3291,35 @@ describe("HeartbeatMonitor", () => {
       );
     });
 
+    it("task_create tracking falls back to parsing text when details.taskId is missing", async () => {
+      const store = createMockStore();
+      const createTaskCreateToolSpy = vi.spyOn(agentTools, "createTaskCreateTool").mockReturnValue({
+        name: "task_create",
+        label: "Create Task",
+        description: "Create a task",
+        parameters: {} as any,
+        execute: vi.fn().mockResolvedValue({
+          content: [{ type: "text", text: "Created PROJ-777: Follow-up task" }],
+          details: {},
+        }),
+      } as any);
+      const monitor = new HeartbeatMonitor({ store, taskStore: mockTaskStore, rootDir: "/tmp" });
+
+      try {
+        const tools = monitor.createHeartbeatTools("agent-001", mockTaskStore, "FN-001");
+        await tools[0]!.execute("call-1", { description: "Follow-up task" }, undefined as any, undefined as any, undefined as any);
+
+        expect(mockTaskStore.logEntry).toHaveBeenCalledWith(
+          "PROJ-777",
+          "Created by agent agent-001 during heartbeat run",
+          undefined,
+          undefined,
+        );
+      } finally {
+        createTaskCreateToolSpy.mockRestore();
+      }
+    });
+
     it("task_create tracking handles missing details gracefully", async () => {
       const store = createMockStore();
       const missingDetailsTaskStore = createMockTaskStoreForTools({

packages/engine/src/agent-heartbeat.ts

@@ -1432,7 +1432,9 @@ export class HeartbeatMonitor {
       execute: async (id: string, params: Static<typeof taskCreateParams>, signal, onUpdate, ctx) => {
         const result = await baseCreateTool.execute(id, params, signal, onUpdate, ctx);
 
-        const createdTaskId = (result.details as { taskId?: string })?.taskId ?? "unknown";
+        const textResponse = result.content.find((item) => item.type === "text")?.text;
+        const taskIdMatch = textResponse?.match(/(?:Created|created) (\w+-\d+):/);
+        const createdTaskId = (result.details as { taskId?: string } | undefined)?.taskId ?? taskIdMatch?.[1] ?? "unknown";
 
         // Log agent link on the created task with run context for correlation
         try {

packages/engine/src/agent-tools.test.ts

@@ -6,6 +6,7 @@ import {
   buildQmdAgentMemoryCollectionAddArgs,
   buildQmdAgentMemorySearchArgs,
   createMemoryTools,
+  createTaskCreateTool,
   createSendMessageTool,
   createReadMessagesTool,
   qmdAgentMemoryCollectionName,
@@ -54,6 +55,41 @@ vi.mock("node:child_process", async () => {
   };
 });
 
+describe("createTaskCreateTool", () => {
+  it("returns details.taskId and keeps Created <id> response text", async () => {
+    const store = {
+      createTask: vi.fn().mockResolvedValue({
+        id: "PROJ-042",
+        description: "Follow-up task",
+        dependencies: ["PROJ-001"],
+        column: "triage",
+      }),
+    };
+
+    const tool = createTaskCreateTool(store as any);
+    const result = await tool.execute(
+      "call-1",
+      {
+        description: "Follow-up task",
+        dependencies: ["PROJ-001"],
+      } as any,
+      undefined,
+      undefined,
+      {} as any,
+    );
+
+    expect(store.createTask).toHaveBeenCalledWith({
+      description: "Follow-up task",
+      dependencies: ["PROJ-001"],
+      column: "triage",
+    });
+    expect(result.details).toEqual({ taskId: "PROJ-042" });
+    const responseText = result.content[0]?.type === "text" ? result.content[0].text : "";
+    expect(responseText).toContain("Created PROJ-042: Follow-up task");
+    expect(responseText).toContain("(depends on: PROJ-001)");
+  });
+});
+
 describe("createMemoryTools", () => {
   let tempDir: string;