diff --git a/packages/cli/src/__tests__/experiment-finalize.test.ts b/packages/cli/src/__tests__/experiment-finalize.test.ts
index 836720c6af..8371b5ceac 100644
--- a/packages/cli/src/__tests__/experiment-finalize.test.ts
+++ b/packages/cli/src/__tests__/experiment-finalize.test.ts
@@ -3,6 +3,21 @@ import { writeFile, mkdtemp } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const previewPlan = vi.fn();
 const finalize = vi.fn();
 const init = vi.fn();
@@ -18,12 +33,12 @@ const mockErrors = vi.hoisted(() => ({
 }));
 
 vi.mock("@fusion/core", () => ({
-  TaskStore: vi.fn(() => ({ init, getExperimentSessionStore })),
+  TaskStore: makeConstructibleMock(() => ({ init, getExperimentSessionStore })),
 }));
 
 vi.mock("@fusion/engine", () => ({
   defaultGitOps: vi.fn(() => ({})),
-  ExperimentFinalizeService: vi.fn(() => ({ previewPlan, finalize })),
+  ExperimentFinalizeService: makeConstructibleMock(() => ({ previewPlan, finalize })),
   ExperimentFinalizeStateError: class extends Error { code = "state_error" as const; },
   ExperimentFinalizeNoKeptRunsError: class extends Error { code = "no_kept_runs" as const; },
   ExperimentFinalizePlanError: class extends Error { code = "plan_error" as const; },
diff --git a/packages/cli/src/__tests__/extension-experiment-finalize.test.ts b/packages/cli/src/__tests__/extension-experiment-finalize.test.ts
index 5def4116bc..6571678896 100644
--- a/packages/cli/src/__tests__/extension-experiment-finalize.test.ts
+++ b/packages/cli/src/__tests__/extension-experiment-finalize.test.ts
@@ -1,5 +1,20 @@
 import { describe, expect, it, vi, beforeEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const previewPlanMock = vi.hoisted(() => vi.fn());
 const finalizeMock = vi.hoisted(() => vi.fn());
 
@@ -18,7 +33,7 @@ const mockErrors = vi.hoisted(() => ({
 }));
 
 vi.mock("@fusion/core", () => ({
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: vi.fn().mockResolvedValue(undefined),
     getExperimentSessionStore: vi.fn(() => ({})),
   })),
@@ -43,7 +58,7 @@ vi.mock("@fusion/engine", () => ({
   createFnAgent: vi.fn(),
   fetchWebContent: vi.fn(),
   defaultGitOps: vi.fn(() => ({})),
-  ExperimentFinalizeService: vi.fn(() => ({ previewPlan: previewPlanMock, finalize: finalizeMock })),
+  ExperimentFinalizeService: makeConstructibleMock(() => ({ previewPlan: previewPlanMock, finalize: finalizeMock })),
   ExperimentFinalizeStateError: mockErrors.StateError,
   ExperimentFinalizeNoKeptRunsError: mockErrors.NoKeptError,
   ExperimentFinalizePlanError: mockErrors.PlanError,
diff --git a/packages/cli/src/__tests__/plugin-dev.test.ts b/packages/cli/src/__tests__/plugin-dev.test.ts
index 4478110a17..54fafba270 100644
--- a/packages/cli/src/__tests__/plugin-dev.test.ts
+++ b/packages/cli/src/__tests__/plugin-dev.test.ts
@@ -3,6 +3,21 @@ import { existsSync, mkdirSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const pluginCommandMocks = vi.hoisted(() => {
   const store = {
     registerPlugin: vi.fn(async () => ({ id: "fusion-plugin-dev-test", enabled: true })),
@@ -16,8 +31,8 @@ const pluginCommandMocks = vi.hoisted(() => {
   return {
     store,
     loader,
-    createPluginStore: vi.fn(async () => store),
-    createPluginLoader: vi.fn(async () => ({ store, loader })),
+    createPluginStore: makeConstructibleMock(async () => store),
+    createPluginLoader: makeConstructibleMock(async () => ({ store, loader })),
     resolvePluginEntryFile: vi.fn(async (dir: string) => join(dir, "dist", "index.js")),
     loadManifestFromPath: vi.fn(async () => ({
       manifest: {
diff --git a/packages/cli/src/__tests__/project-resolver.test.ts b/packages/cli/src/__tests__/project-resolver.test.ts
index e9ade98c36..4240c2e6bc 100644
--- a/packages/cli/src/__tests__/project-resolver.test.ts
+++ b/packages/cli/src/__tests__/project-resolver.test.ts
@@ -2,6 +2,21 @@ import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { existsSync, statSync } from "node:fs";
 import { TaskStore } from "@fusion/core";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const { mockIsValidSqliteDatabaseFile } = vi.hoisted(() => ({
   mockIsValidSqliteDatabaseFile: vi.fn(),
 }));
@@ -41,7 +56,7 @@ vi.mock("@fusion/core", async () => {
     },
     isValidSqliteDatabaseFile: (...args: Parameters<typeof mockIsValidSqliteDatabaseFile>) =>
       mockIsValidSqliteDatabaseFile(...args),
-    TaskStore: vi.fn().mockImplementation(() => ({
+    TaskStore: makeConstructibleMock(() => ({
       init: vi.fn().mockResolvedValue(undefined),
       listTasks: vi.fn().mockResolvedValue([]),
     })),
diff --git a/packages/cli/src/__tests__/task-plan.test.ts b/packages/cli/src/__tests__/task-plan.test.ts
index a8ae3ebd3b..1a6f224bb9 100644
--- a/packages/cli/src/__tests__/task-plan.test.ts
+++ b/packages/cli/src/__tests__/task-plan.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 // Mock node:readline/promises before importing
 vi.mock("node:readline/promises", () => ({
   createInterface: vi.fn(),
@@ -8,7 +23,7 @@ vi.mock("node:readline/promises", () => ({
 // Mock @fusion/core before importing
 vi.mock("@fusion/core", async (importOriginal) => ({
   ...(await importOriginal<typeof import("@fusion/core")>()),
-  TaskStore: vi.fn(),
+  TaskStore: makeConstructibleMock(),
   COLUMNS: ["triage", "todo", "in-progress", "in-review", "done", "archived"],
   COLUMN_LABELS: {
     triage: "Triage",
diff --git a/packages/cli/src/__tests__/task-steer.test.ts b/packages/cli/src/__tests__/task-steer.test.ts
index bec5070b4d..4bc8becb4c 100644
--- a/packages/cli/src/__tests__/task-steer.test.ts
+++ b/packages/cli/src/__tests__/task-steer.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 // Mock node:readline/promises before importing
 vi.mock("node:readline/promises", () => ({
   createInterface: vi.fn(),
@@ -8,7 +23,7 @@ vi.mock("node:readline/promises", () => ({
 // Mock @fusion/core before importing
 vi.mock("@fusion/core", async (importOriginal) => ({
   ...(await importOriginal<typeof import("@fusion/core")>()),
-  TaskStore: vi.fn(),
+  TaskStore: makeConstructibleMock(),
   COLUMNS: ["triage", "todo", "in-progress", "in-review", "done", "archived"],
   COLUMN_LABELS: {
     triage: "Triage",
diff --git a/packages/cli/src/__tests__/update-cache.test.ts b/packages/cli/src/__tests__/update-cache.test.ts
index a3b3f7747c..802b38ddf3 100644
--- a/packages/cli/src/__tests__/update-cache.test.ts
+++ b/packages/cli/src/__tests__/update-cache.test.ts
@@ -2,6 +2,21 @@ import { beforeEach, describe, expect, it, vi } from "vitest";
 import { mkdirSync, rmSync, writeFileSync } from "node:fs";
 import { readFileSync } from "node:fs";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const CLI_PACKAGE_VERSION = (
   JSON.parse(readFileSync(new URL("../../package.json", import.meta.url), "utf-8")) as { version: string }
 ).version;
@@ -16,7 +31,7 @@ const { cacheDir, mockResolveGlobalDir } = vi.hoisted(() => {
 
 vi.mock("@fusion/core", () => ({
   resolveGlobalDir: mockResolveGlobalDir,
-  GlobalSettingsStore: vi.fn(),
+  GlobalSettingsStore: makeConstructibleMock(),
 }));
 
 const { getCachedUpdateStatus } = await import("../update-cache.js");
diff --git a/packages/cli/src/commands/__tests__/agent.test.ts b/packages/cli/src/commands/__tests__/agent.test.ts
index 735c52ef93..df2793908f 100644
--- a/packages/cli/src/commands/__tests__/agent.test.ts
+++ b/packages/cli/src/commands/__tests__/agent.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 // ── Mock AgentStore ──────────────────────────────────────────────────
 
 const mockGetAgent = vi.fn();
@@ -9,7 +24,7 @@ const mockInit = vi.fn().mockResolvedValue(undefined);
 // AgentStore mock — vi.fn() with mockImplementation works with `new` in vitest.
 // We return a plain object from the constructor which becomes the instance.
 vi.mock("@fusion/core", () => ({
-  AgentStore: vi.fn().mockImplementation(() => ({
+  AgentStore: makeConstructibleMock(() => ({
     init: mockInit,
     getAgent: mockGetAgent,
     updateAgentState: mockUpdateAgentState,
diff --git a/packages/cli/src/commands/__tests__/backup.test.ts b/packages/cli/src/commands/__tests__/backup.test.ts
index ceca9eed1c..acfe564b3b 100644
--- a/packages/cli/src/commands/__tests__/backup.test.ts
+++ b/packages/cli/src/commands/__tests__/backup.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const {
   mockListBackups,
   mockListBackupPairs,
@@ -20,7 +35,7 @@ const {
 
 vi.mock("@fusion/core", () => ({
   BackupManager: vi.fn(),
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: vi.fn().mockResolvedValue(undefined),
     getSettings: mockGetSettings,
     fusionDir: "/cwd/.fusion",
diff --git a/packages/cli/src/commands/__tests__/db.test.ts b/packages/cli/src/commands/__tests__/db.test.ts
index b209e3f5ec..61f3368971 100644
--- a/packages/cli/src/commands/__tests__/db.test.ts
+++ b/packages/cli/src/commands/__tests__/db.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 // Hoist mocks so they are evaluated before module imports
 const { mockGetDatabase, mockVacuum, mockResolveProject } = vi.hoisted(() => ({
   mockGetDatabase: vi.fn(),
@@ -8,7 +23,7 @@ const { mockGetDatabase, mockVacuum, mockResolveProject } = vi.hoisted(() => ({
 }));
 
 vi.mock("@fusion/core", () => ({
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: vi.fn(),
     getDatabase: mockGetDatabase,
   })),
diff --git a/packages/cli/src/commands/__tests__/desktop.test.ts b/packages/cli/src/commands/__tests__/desktop.test.ts
index f6cb0a18b0..6e662d41c9 100644
--- a/packages/cli/src/commands/__tests__/desktop.test.ts
+++ b/packages/cli/src/commands/__tests__/desktop.test.ts
@@ -122,7 +122,9 @@ const mocks = vi.hoisted(() => {
     server,
     app,
     spawn,
-    taskStoreCtor: vi.fn(() => store),
+    taskStoreCtor: vi.fn(function () {
+      return store;
+    }),
     createServer: vi.fn(() => app),
   };
 });
diff --git a/packages/cli/src/commands/__tests__/init.test.ts b/packages/cli/src/commands/__tests__/init.test.ts
index a6cbc68477..1313ed238a 100644
--- a/packages/cli/src/commands/__tests__/init.test.ts
+++ b/packages/cli/src/commands/__tests__/init.test.ts
@@ -11,6 +11,21 @@ import { exec } from "node:child_process";
 import { promisify } from "node:util";
 import { GitRepositoryInitializationError } from "@fusion/core";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const execAsync = promisify(exec);
 
 const mockCentralInit = vi.fn();
@@ -27,7 +42,7 @@ vi.mock("@fusion/core", async () => {
   const actual = await vi.importActual<typeof import("@fusion/core")>("@fusion/core");
   return {
     ...actual,
-    CentralCore: vi.fn().mockImplementation(() => ({
+    CentralCore: makeConstructibleMock(() => ({
       init: mockCentralInit,
       close: mockCentralClose,
       getProjectByPath: mockGetProjectByPath,
diff --git a/packages/cli/src/commands/__tests__/memory-backup.test.ts b/packages/cli/src/commands/__tests__/memory-backup.test.ts
index 8813a33c16..b174371c6f 100644
--- a/packages/cli/src/commands/__tests__/memory-backup.test.ts
+++ b/packages/cli/src/commands/__tests__/memory-backup.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const {
   mockListBackups,
   mockRestoreBackup,
@@ -15,7 +30,7 @@ const {
 }));
 
 vi.mock("@fusion/core", () => ({
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: vi.fn().mockResolvedValue(undefined),
     getSettings: mockGetSettings,
     fusionDir: "/cwd/.fusion",
diff --git a/packages/cli/src/commands/__tests__/message.test.ts b/packages/cli/src/commands/__tests__/message.test.ts
index 1ebc147915..74bb36914c 100644
--- a/packages/cli/src/commands/__tests__/message.test.ts
+++ b/packages/cli/src/commands/__tests__/message.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 // ── Mock MessageStore ────────────────────────────────────────────────
 
 const mockGetInbox = vi.fn();
@@ -17,7 +32,7 @@ vi.mock("@fusion/core", () => {
   };
   return {
     createDatabase: vi.fn().mockReturnValue(mockDb),
-    MessageStore: vi.fn().mockImplementation(() => ({
+    MessageStore: makeConstructibleMock(() => ({
       getInbox: mockGetInbox,
       getOutbox: mockGetOutbox,
       getMailbox: mockGetMailbox,
diff --git a/packages/cli/src/commands/__tests__/node.test.ts b/packages/cli/src/commands/__tests__/node.test.ts
index 9fc22510d8..2b4800b9db 100644
--- a/packages/cli/src/commands/__tests__/node.test.ts
+++ b/packages/cli/src/commands/__tests__/node.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const mockInit = vi.fn().mockResolvedValue(undefined);
 const mockClose = vi.fn().mockResolvedValue(undefined);
 const mockListNodes = vi.fn();
@@ -13,7 +28,7 @@ const mockQuestion = vi.fn();
 const mockRlClose = vi.fn();
 
 vi.mock("@fusion/core", () => ({
-  CentralCore: vi.fn().mockImplementation(() => ({
+  CentralCore: makeConstructibleMock(() => ({
     init: mockInit,
     close: mockClose,
     listNodes: mockListNodes,
diff --git a/packages/cli/src/commands/__tests__/plugin.test.ts b/packages/cli/src/commands/__tests__/plugin.test.ts
index 3a0b8e771f..d70109d9f1 100644
--- a/packages/cli/src/commands/__tests__/plugin.test.ts
+++ b/packages/cli/src/commands/__tests__/plugin.test.ts
@@ -3,6 +3,21 @@ import { dirname, join, resolve } from "node:path";
 import { tmpdir } from "node:os";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const mocks = vi.hoisted(() => {
   const pluginStoreInstances: Array<{
     init: ReturnType<typeof vi.fn>;
@@ -15,9 +30,9 @@ const mocks = vi.hoisted(() => {
   let loaderTaskStore: { getRootDir?: () => string } | undefined;
   let loaderRootDir: string | undefined;
 
-  const PluginStore = vi.fn();
+  const PluginStore = makeConstructibleMock();
 
-  const PluginLoader = vi.fn();
+  const PluginLoader = makeConstructibleMock();
 
   const setupDefaults = () => {
     PluginStore.mockImplementation(() => {
diff --git a/packages/cli/src/commands/__tests__/project.test.ts b/packages/cli/src/commands/__tests__/project.test.ts
index 5fc892ef39..7d813a7d10 100644
--- a/packages/cli/src/commands/__tests__/project.test.ts
+++ b/packages/cli/src/commands/__tests__/project.test.ts
@@ -3,6 +3,21 @@
  */
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const mockListProjects = vi.fn();
 const mockRegisterProject = vi.fn();
 const mockEnsureProjectForPath = vi.fn(async (...args: unknown[]) => ({
@@ -29,7 +44,7 @@ const mockEnsureMemoryFileWithBackend = vi.fn();
 
 // Mock @fusion/core
 vi.mock("@fusion/core", () => ({
-  CentralCore: vi.fn().mockImplementation(() => ({
+  CentralCore: makeConstructibleMock(() => ({
     init: mockInit.mockResolvedValue(undefined),
     close: mockClose.mockResolvedValue(undefined),
     listProjects: mockListProjects,
@@ -41,11 +56,11 @@ vi.mock("@fusion/core", () => ({
     getProjectByPath: mockGetProjectByPath,
     getProjectHealth: mockGetProjectHealth,
   })),
-  GlobalSettingsStore: vi.fn().mockImplementation(() => ({
+  GlobalSettingsStore: makeConstructibleMock(() => ({
     init: mockGlobalInit.mockResolvedValue(undefined),
     getSettings: mockGetSettings,
   })),
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: mockTaskStoreInit,
     listTasks: mockTaskStoreListTasks,
   })),
diff --git a/packages/cli/src/commands/__tests__/serve.test.ts b/packages/cli/src/commands/__tests__/serve.test.ts
index 994c732186..d1c7a9bf7d 100644
--- a/packages/cli/src/commands/__tests__/serve.test.ts
+++ b/packages/cli/src/commands/__tests__/serve.test.ts
@@ -4,6 +4,21 @@ import { mkdtempSync, rmSync } from "node:fs";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const { mockSyncStartupModels, mockShouldUseHybridExecutor, mockHybridExecutorCtor, mockHybridExecutorInitialize, mockHybridExecutorShutdown } = vi.hoisted(() => ({
   mockSyncStartupModels: vi.fn().mockResolvedValue(undefined),
   mockShouldUseHybridExecutor: vi.fn().mockResolvedValue({ enabled: false, reason: "single-project-local-only" }),
@@ -590,7 +605,7 @@ vi.mock("@fusion/core", async (importOriginal) => {
       storeToken: vi.fn().mockResolvedValue(undefined),
     };
   }),
-  GlobalSettingsStore: vi.fn().mockImplementation(function () {
+  GlobalSettingsStore: makeConstructibleMock(function () {
     return {};
   }),
   resolveGlobalDir: vi.fn().mockReturnValue("/mock/global"),
diff --git a/packages/cli/src/commands/__tests__/settings-export.test.ts b/packages/cli/src/commands/__tests__/settings-export.test.ts
index 626131f94e..56ec19ed0f 100644
--- a/packages/cli/src/commands/__tests__/settings-export.test.ts
+++ b/packages/cli/src/commands/__tests__/settings-export.test.ts
@@ -4,6 +4,21 @@ import { join, resolve } from "node:path";
 import { TaskStore, exportSettings, generateExportFilename } from "@fusion/core";
 import { resolveProject } from "../../project-context.js";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const mockStoreInit = vi.fn().mockResolvedValue(undefined);
 
 vi.mock("node:fs/promises", () => ({
@@ -11,7 +26,7 @@ vi.mock("node:fs/promises", () => ({
 }));
 
 vi.mock("@fusion/core", () => ({
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: mockStoreInit,
   })),
   exportSettings: vi.fn(),
diff --git a/packages/cli/src/commands/__tests__/settings-import.test.ts b/packages/cli/src/commands/__tests__/settings-import.test.ts
index 1dc563b4d3..5b33dff5be 100644
--- a/packages/cli/src/commands/__tests__/settings-import.test.ts
+++ b/packages/cli/src/commands/__tests__/settings-import.test.ts
@@ -3,6 +3,21 @@ import { existsSync } from "node:fs";
 import { TaskStore, importSettings, readExportFile, validateImportData } from "@fusion/core";
 import { resolveProject } from "../../project-context.js";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 const mockStoreInit = vi.fn().mockResolvedValue(undefined);
 
 vi.mock("node:fs", () => ({
@@ -10,7 +25,7 @@ vi.mock("node:fs", () => ({
 }));
 
 vi.mock("@fusion/core", () => ({
-  TaskStore: vi.fn().mockImplementation(() => ({
+  TaskStore: makeConstructibleMock(() => ({
     init: mockStoreInit,
   })),
   importSettings: vi.fn(),
diff --git a/packages/cli/src/commands/__tests__/settings.test.ts b/packages/cli/src/commands/__tests__/settings.test.ts
index de9772e093..364a10aa58 100644
--- a/packages/cli/src/commands/__tests__/settings.test.ts
+++ b/packages/cli/src/commands/__tests__/settings.test.ts
@@ -1,5 +1,20 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
+function makeConstructibleMock<T extends (...args: any[]) => unknown>(impl?: T) {
+  const mock = vi.fn(function () {});
+  const originalMockImplementation = mock.mockImplementation.bind(mock);
+  const originalMockImplementationOnce = mock.mockImplementationOnce.bind(mock);
+  const wrap = (nextImpl: T) => function (this: unknown, ...args: Parameters<T>) {
+    return nextImpl(...args);
+  };
+  mock.mockImplementation = ((nextImpl: T) => originalMockImplementation(wrap(nextImpl))) as typeof mock.mockImplementation;
+  mock.mockImplementationOnce = ((nextImpl: T) => originalMockImplementationOnce(wrap(nextImpl))) as typeof mock.mockImplementationOnce;
+  if (impl) {
+    mock.mockImplementation(impl);
+  }
+  return mock;
+}
+
 vi.mock("@fusion/core", () => {
   const DEFAULT_SETTINGS = {
     maxConcurrent: 2,
@@ -23,7 +38,7 @@ vi.mock("@fusion/core", () => {
   };
 
   return {
-    GlobalSettingsStore: vi.fn(),
+    GlobalSettingsStore: makeConstructibleMock(),
     DEFAULT_SETTINGS,
     SUPPORTED_LOCALES: ["en", "zh-CN", "zh-TW", "fr", "es", "ko"],
     resolveWorktrunkSettings: (globalValue: any, projectValue: any) => ({
diff --git a/packages/cli/src/commands/__tests__/task.test.ts b/packages/cli/src/commands/__tests__/task.test.ts
index 0363711814..6b4e569ef7 100644
--- a/packages/cli/src/commands/__tests__/task.test.ts
+++ b/packages/cli/src/commands/__tests__/task.test.ts
@@ -2460,6 +2460,7 @@ describe("runTaskRetry", () => {
       reviewerContextRetryCount: 0,
       reviewerFallbackRetryCount: 0,
       completionHandoffLimboRecoveryCount: 0,
+      graphResumeRetryCount: 0,
       mergeAuditBounceCount: 0,
       mergeRetries: 0,
       resumeLimboCount: 0,
@@ -2534,6 +2535,7 @@ describe("runTaskRetry", () => {
       reviewerContextRetryCount: 0,
       reviewerFallbackRetryCount: 0,
       completionHandoffLimboRecoveryCount: 0,
+      graphResumeRetryCount: 0,
       mergeAuditBounceCount: 0,
       mergeRetries: 0,
       resumeLimboCount: 0,