diff --git a/.changeset/fn-7405-task-detail-model-project-scope.md b/.changeset/fn-7405-task-detail-model-project-scope.md
new file mode 100644
index 0000000000..f989ce09e3
--- /dev/null
+++ b/.changeset/fn-7405-task-detail-model-project-scope.md
@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Preserve project scope when saving task-detail model overrides.
+category: fix
+dev: Threads task-detail Model tab updates through projectId for executor, reviewer, planning, and thinking lanes.
diff --git a/packages/dashboard/app/components/ModelSelectorTab.tsx b/packages/dashboard/app/components/ModelSelectorTab.tsx
index 23ec9e6bc9..2d28113c1d 100644
--- a/packages/dashboard/app/components/ModelSelectorTab.tsx
+++ b/packages/dashboard/app/components/ModelSelectorTab.tsx
@@ -21,6 +21,7 @@ interface ModelSelectorTabProps {
   addToast: (message: string, type?: ToastType) => void;
   onTaskUpdated?: (task: Task) => void;
   settings?: Settings;
+  projectId?: string;
 }
 
 interface ModelSelection {
@@ -120,7 +121,7 @@ function getSuccessToastMessage(
   });
 }
 
-export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings }: ModelSelectorTabProps) {
+export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, projectId }: ModelSelectorTabProps) {
   const { t } = useTranslation("app");
   const {
     availableModels,
@@ -220,7 +221,11 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings }: Mo
               planningModelId: (target === "planning" ? nextSelection : savedPlanning).modelId ?? null,
             };
 
-        const updatedTask = await updateTask(requestTaskId, updates);
+        /*
+        FNXC:TaskDetailModels 2026-07-01-00:00:
+        Task-detail model saves must carry the active project id through the shared update API. Multi-project task detail views can otherwise patch the default project route and surface a false "Task not found" toast for existing scoped tasks.
+        */
+        const updatedTask = await updateTask(requestTaskId, updates, projectId);
 
         if (activeTaskIdRef.current !== requestTaskId) {
           return;
@@ -268,7 +273,7 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings }: Mo
         }
       }
     },
-    [task.id, savedExecutor, savedValidator, savedPlanning, addToast, onTaskUpdated, t],
+    [task.id, savedExecutor, savedValidator, savedPlanning, addToast, onTaskUpdated, projectId, t],
   );
 
   const handleExecutorChange = useCallback(
@@ -326,7 +331,7 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings }: Mo
       try {
         const updatedTask = await updateTask(requestTaskId, {
           thinkingLevel: nextValue,
-        });
+        }, projectId);
 
         if (activeTaskIdRef.current !== requestTaskId) {
           return;
@@ -362,7 +367,7 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings }: Mo
         }
       }
     },
-    [task.id, savedThinking, settings, addToast, onTaskUpdated, t],
+    [task.id, savedThinking, settings, addToast, onTaskUpdated, projectId, t],
   );
 
   const executorUsingDefault = !savedExecutor.provider && !savedExecutor.modelId;
diff --git a/packages/dashboard/app/components/TaskDetailModal.tsx b/packages/dashboard/app/components/TaskDetailModal.tsx
index 5f8be7cfd7..09953efd4f 100644
--- a/packages/dashboard/app/components/TaskDetailModal.tsx
+++ b/packages/dashboard/app/components/TaskDetailModal.tsx
@@ -3620,7 +3620,13 @@ export function TaskDetailContent({
             </div>
           ) : activeTab === "model" ? (
             <div className="detail-section">
-              <ModelSelectorTab task={task} addToast={addToast} onTaskUpdated={onTaskUpdated} settings={settings} />
+              <ModelSelectorTab
+                task={task}
+                addToast={addToast}
+                onTaskUpdated={onTaskUpdated}
+                settings={settings}
+                projectId={projectId}
+              />
             </div>
           ) : activeTab === "summary" && task.column === "done" ? (
             <div className="detail-section detail-section--summary">
diff --git a/packages/dashboard/app/components/__tests__/ModelSelectorTab.test.tsx b/packages/dashboard/app/components/__tests__/ModelSelectorTab.test.tsx
index eb34d0c1b5..e61d855fe7 100644
--- a/packages/dashboard/app/components/__tests__/ModelSelectorTab.test.tsx
+++ b/packages/dashboard/app/components/__tests__/ModelSelectorTab.test.tsx
@@ -29,6 +29,12 @@ function makeTask(overrides: Partial<TaskDetail> = {}): TaskDetail {
   } as unknown as TaskDetail;
 }
 
+async function selectDropdownOption(user: ReturnType<typeof userEvent.setup>, label: string, option: string) {
+  await user.click(screen.getByLabelText(label));
+  const listbox = await screen.findByRole("listbox");
+  await user.click(within(listbox).getByText(option));
+}
+
 describe("ModelSelectorTab", () => {
   beforeEach(() => {
     vi.clearAllMocks();
@@ -76,7 +82,7 @@ describe("ModelSelectorTab", () => {
       expect(mockUpdateTask).toHaveBeenCalledWith("FN-7398", {
         modelProvider: "pi-claude-cli",
         modelId: "claude-sonnet-5",
-      });
+      }, undefined);
       expect(onTaskUpdated).toHaveBeenCalledWith(expect.objectContaining({
         modelProvider: "pi-claude-cli",
         modelId: "claude-sonnet-5",
@@ -84,6 +90,125 @@ describe("ModelSelectorTab", () => {
     });
   });
 
+  it("passes the scoped project id for executor, reviewer, planning, and thinking saves", async () => {
+    const user = userEvent.setup();
+    const addToast = vi.fn();
+    const onTaskUpdated = vi.fn();
+    const task = makeTask({
+      modelProvider: "pi-claude-cli",
+      modelId: "claude-haiku-5",
+      validatorModelProvider: "pi-claude-cli",
+      validatorModelId: "claude-haiku-5",
+      planningModelProvider: "pi-claude-cli",
+      planningModelId: "claude-haiku-5",
+      thinkingLevel: "minimal",
+    });
+
+    mockFetchModels.mockResolvedValue({
+      models: [
+        { provider: "pi-claude-cli", id: "claude-haiku-5", name: "Claude Haiku 5 (CLI)", reasoning: true, contextWindow: 200_000 },
+        { provider: "pi-claude-cli", id: "claude-sonnet-5", name: "Claude Sonnet 5 (CLI)", reasoning: true, contextWindow: 1_000_000 },
+      ],
+      favoriteProviders: [],
+      favoriteModels: [],
+    });
+    mockUpdateTask
+      .mockResolvedValueOnce({
+        ...task,
+        modelProvider: "pi-claude-cli",
+        modelId: "claude-sonnet-5",
+      })
+      .mockResolvedValueOnce({
+        ...task,
+        validatorModelProvider: "pi-claude-cli",
+        validatorModelId: "claude-sonnet-5",
+      })
+      .mockResolvedValueOnce({
+        ...task,
+        planningModelProvider: "pi-claude-cli",
+        planningModelId: "claude-sonnet-5",
+      })
+      .mockResolvedValueOnce({
+        ...task,
+        thinkingLevel: "high",
+      });
+
+    render(
+      <ModelSelectorTab
+        task={task}
+        addToast={addToast}
+        onTaskUpdated={onTaskUpdated}
+        projectId="project-alpha"
+      />,
+    );
+
+    await waitFor(() => expect(screen.getByLabelText("Executor Model")).toBeInTheDocument());
+
+    await selectDropdownOption(user, "Executor Model", "Claude Sonnet 5 (CLI)");
+    await waitFor(() => {
+      expect(mockUpdateTask).toHaveBeenNthCalledWith(1, "FN-7398", {
+        modelProvider: "pi-claude-cli",
+        modelId: "claude-sonnet-5",
+      }, "project-alpha");
+    });
+
+    await selectDropdownOption(user, "Reviewer Model", "Claude Sonnet 5 (CLI)");
+    await waitFor(() => {
+      expect(mockUpdateTask).toHaveBeenNthCalledWith(2, "FN-7398", {
+        validatorModelProvider: "pi-claude-cli",
+        validatorModelId: "claude-sonnet-5",
+      }, "project-alpha");
+    });
+
+    await selectDropdownOption(user, "Planning Model", "Claude Sonnet 5 (CLI)");
+    await waitFor(() => {
+      expect(mockUpdateTask).toHaveBeenNthCalledWith(3, "FN-7398", {
+        planningModelProvider: "pi-claude-cli",
+        planningModelId: "claude-sonnet-5",
+      }, "project-alpha");
+    });
+
+    await user.selectOptions(screen.getByLabelText("Thinking Level"), "high");
+    await waitFor(() => {
+      expect(mockUpdateTask).toHaveBeenNthCalledWith(4, "FN-7398", {
+        thinkingLevel: "high",
+      }, "project-alpha");
+    });
+    expect(addToast).toHaveBeenCalledWith(expect.stringContaining("set to"), "success");
+  });
+
+  it("clears model overrides with the scoped project id", async () => {
+    const user = userEvent.setup();
+    const task = makeTask({
+      modelProvider: "pi-claude-cli",
+      modelId: "claude-sonnet-5",
+    });
+    mockUpdateTask.mockResolvedValueOnce({
+      ...task,
+      modelProvider: null,
+      modelId: null,
+    });
+
+    render(
+      <ModelSelectorTab
+        task={task}
+        addToast={vi.fn()}
+        onTaskUpdated={vi.fn()}
+        projectId="project-alpha"
+      />,
+    );
+
+    await waitFor(() => expect(screen.getByLabelText("Executor Model")).toBeInTheDocument());
+    await selectDropdownOption(user, "Executor Model", "Use default");
+
+    await waitFor(() => {
+      expect(mockUpdateTask).toHaveBeenCalledWith("FN-7398", {
+        modelProvider: null,
+        modelId: null,
+      }, "project-alpha");
+    });
+  });
+
   it("updates from a cached empty catalog to populated Claude CLI rows without remounting", async () => {
     localStorage.setItem(
       SWR_CACHE_KEYS.MODELS,
diff --git a/packages/dashboard/app/components/__tests__/TaskDetailModal.inline-editing-and-integrations.test.tsx b/packages/dashboard/app/components/__tests__/TaskDetailModal.inline-editing-and-integrations.test.tsx
index ad04d416df..aec68bf6fc 100644
--- a/packages/dashboard/app/components/__tests__/TaskDetailModal.inline-editing-and-integrations.test.tsx
+++ b/packages/dashboard/app/components/__tests__/TaskDetailModal.inline-editing-and-integrations.test.tsx
@@ -3,7 +3,7 @@ FNXC:TaskDetailTabs 2026-06-17-08:20:
 FN-7306 labels the stable internal `chat` tab as Activity and keeps it as the default TaskDetailModal tab. Tests that assert Definition-only sections must opt into `initialTab="definition"` so they verify the intended surface instead of the Activity landing state.
 */
 import { describe, it, expect, vi } from "vitest";
-import { useState } from "react";
+import { useState, type Dispatch, type SetStateAction } from "react";
 import { render, screen, fireEvent, act, waitFor } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import type { Task, TaskDetail } from "@fusion/core";
@@ -1555,7 +1555,7 @@ describe("TaskDetailModal", () => {
       }, { timeout: 3500 });
     });
 
-    it("uses updated model values in edit mode after saving from the Model tab", async () => {
+    it("saves task-detail model changes with the active project id", async () => {
       const { fetchModels, updateTask } = await import("../../api");
       const mockFetchModels = vi.mocked(fetchModels);
       const mockUpdateTask = vi.mocked(updateTask);
@@ -1587,20 +1587,28 @@ describe("TaskDetailModal", () => {
         .mockResolvedValueOnce(updatedAfterExecutor)
         .mockResolvedValueOnce(updatedAfterValidator);
 
+      const addToast = vi.fn();
+      const onTaskUpdated = vi.fn((updated: Task) => {
+        setStatefulTask((prev) => ({ ...prev, ...updated }));
+      });
+      let setStatefulTask: Dispatch<SetStateAction<TaskDetail>>;
+
       function StatefulModal() {
         const [task, setTask] = useState<TaskDetail>(initialTask);
+        setStatefulTask = setTask;
 
         return (
           <TaskDetailModal
             initialTab="definition"
             task={task}
+            projectId="project-alpha"
             onClose={noop}
             onMoveTask={noopMove}
             onDeleteTask={noopDelete}
             onMergeTask={noopMerge}
             onOpenDetail={noopOpenDetail}
-            onTaskUpdated={(updated) => setTask((prev) => ({ ...prev, ...updated }))}
-            addToast={noop}
+            onTaskUpdated={onTaskUpdated}
+            addToast={addToast}
           />
         );
       }
@@ -1623,6 +1631,7 @@ describe("TaskDetailModal", () => {
             modelProvider: "anthropic",
             modelId: "claude-sonnet-4-5",
           }),
+          "project-alpha",
         );
       });
 
@@ -1637,7 +1646,13 @@ describe("TaskDetailModal", () => {
             validatorModelProvider: "openai",
             validatorModelId: "gpt-4o",
           },
+          "project-alpha",
         );
+        expect(onTaskUpdated).toHaveBeenCalledWith(expect.objectContaining({
+          validatorModelProvider: "openai",
+          validatorModelId: "gpt-4o",
+        }));
+        expect(addToast).not.toHaveBeenCalledWith(expect.any(String), "error");
       });
 
       fireEvent.click(container.querySelector(".modal-edit-btn")!);
@@ -1648,6 +1663,59 @@ describe("TaskDetailModal", () => {
       });
     });
 
+    it("rolls back the scoped reviewer model change and shows one error toast on real failure", async () => {
+      const { fetchModels, updateTask } = await import("../../api");
+      const mockFetchModels = vi.mocked(fetchModels);
+      const mockUpdateTask = vi.mocked(updateTask);
+      const user = userEvent.setup();
+      const addToast = vi.fn();
+
+      mockFetchModels.mockResolvedValue({
+        models: [
+          { provider: "anthropic", id: "claude-haiku-5", name: "Claude Haiku 5", reasoning: true, contextWindow: 200000 },
+          { provider: "openai", id: "gpt-4o", name: "GPT-4o", reasoning: false, contextWindow: 128000 },
+        ],
+        favoriteProviders: [],
+        favoriteModels: [],
+      });
+      mockUpdateTask.mockRejectedValueOnce(new Error("Task not found"));
+
+      render(
+        <TaskDetailModal
+          initialTab="model"
+          task={makeTask({
+            id: "FN-001",
+            column: "triage",
+            title: "Scoped reviewer failure",
+            validatorModelProvider: "anthropic",
+            validatorModelId: "claude-haiku-5",
+          })}
+          projectId="project-alpha"
+          onClose={noop}
+          onMoveTask={noopMove}
+          onDeleteTask={noopDelete}
+          onMergeTask={noopMerge}
+          onOpenDetail={noopOpenDetail}
+          onTaskUpdated={vi.fn()}
+          addToast={addToast}
+        />,
+      );
+
+      await waitFor(() => expect(screen.getByLabelText("Reviewer Model")).toBeInTheDocument());
+      await user.click(screen.getByLabelText("Reviewer Model"));
+      await user.click(await screen.findByText("GPT-4o"));
+
+      await waitFor(() => {
+        expect(mockUpdateTask).toHaveBeenCalledWith("FN-001", {
+          validatorModelProvider: "openai",
+          validatorModelId: "gpt-4o",
+        }, "project-alpha");
+        expect(addToast).toHaveBeenCalledTimes(1);
+        expect(addToast).toHaveBeenCalledWith("Task not found", "error");
+        expect(screen.getByLabelText("Reviewer Model")).toHaveTextContent("Claude Haiku 5");
+      });
+    });
+
     it("renders Save and Cancel in the modal footer, not inside the edit form body", () => {
       const { container } = render(
         <TaskDetailModal