diff --git a/.changeset/fn-6532-chat-first-task-detail.md b/.changeset/fn-6532-chat-first-task-detail.md
new file mode 100644
index 0000000000..b74868f798
--- /dev/null
+++ b/.changeset/fn-6532-chat-first-task-detail.md
@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Make Chat the first tab and default active view in the task detail modal while preserving explicit initial tab requests.
diff --git a/packages/dashboard/app/components/TaskDetailModal.tsx b/packages/dashboard/app/components/TaskDetailModal.tsx
index 9198613c74..a3a402372b 100644
--- a/packages/dashboard/app/components/TaskDetailModal.tsx
+++ b/packages/dashboard/app/components/TaskDetailModal.tsx
@@ -375,7 +375,7 @@ export interface TaskDetailModalProps {
   prAuthAvailable?: boolean;
   autoMergeEnabled?: boolean;
   onOpenWorkflowEditor?: () => void;
-  /** Open the modal with this tab active instead of "definition" */
+  /** Open the modal with this tab active instead of the default Chat view. */
   initialTab?: TabId;
   /** Mobile-only header affordance mode. */
   mobileHeaderMode?: "close" | "back";
@@ -555,7 +555,11 @@ export function TaskDetailContent({
   prAuthAvailable,
   autoMergeEnabled: autoMergeEnabledProp,
   onOpenWorkflowEditor,
-  initialTab = "definition",
+  /**
+   * FNXC:TaskDetailTabs 2026-06-17-00:00:
+   * FN-6532 makes Chat the default task-detail view when no caller supplies an explicit initial tab.
+   */
+  initialTab = "chat",
   mobileHeaderMode = "close",
   embedded = false,
   onRequestClose,
@@ -3063,18 +3067,22 @@ export function TaskDetailContent({
           {!isEditing && (
             <>
           <div className="detail-tabs">
-            <button
-              className={`detail-tab${activeTab === "definition" ? " detail-tab-active" : ""}`}
-              onClick={() => setActiveTab("definition")}
-            >
-              {t("taskDetail.tabs.definition", "Definition")}
-            </button>
+            {/*
+              FNXC:TaskDetailTabs 2026-06-17-00:00:
+              FN-6532 requires Chat to be the first task-detail tab while preserving every explicit tab entrypoint.
+            */}
             <button
               className={`detail-tab${activeTab === "chat" ? " detail-tab-active" : ""}`}
               onClick={() => setActiveTab("chat")}
             >
               {t("taskDetail.tabs.chat", "Chat")}
             </button>
+            <button
+              className={`detail-tab${activeTab === "definition" ? " detail-tab-active" : ""}`}
+              onClick={() => setActiveTab("definition")}
+            >
+              {t("taskDetail.tabs.definition", "Definition")}
+            </button>
             <button
               className={`detail-tab${activeTab === "logs" ? " detail-tab-active" : ""}`}
               onClick={() => setActiveTab("logs")}
diff --git a/packages/dashboard/app/components/__tests__/AppModals.test.tsx b/packages/dashboard/app/components/__tests__/AppModals.test.tsx
index dcfe4ba272..b866c8ec31 100644
--- a/packages/dashboard/app/components/__tests__/AppModals.test.tsx
+++ b/packages/dashboard/app/components/__tests__/AppModals.test.tsx
@@ -162,7 +162,7 @@ describe("AppModals", () => {
   const mockModalManager: ModalManager = {
     // State
     detailTask: null,
-    detailTaskInitialTab: "definition",
+    detailTaskInitialTab: "chat",
     settingsOpen: false,
     settingsInitialSection: undefined,
     githubImportOpen: false,
diff --git a/packages/dashboard/app/components/__tests__/TaskDetailModal.attachments-and-tabs.test.tsx b/packages/dashboard/app/components/__tests__/TaskDetailModal.attachments-and-tabs.test.tsx
index 89849e3308..f40c4505a9 100644
--- a/packages/dashboard/app/components/__tests__/TaskDetailModal.attachments-and-tabs.test.tsx
+++ b/packages/dashboard/app/components/__tests__/TaskDetailModal.attachments-and-tabs.test.tsx
@@ -75,6 +75,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask()}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -114,6 +115,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask()}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -202,6 +204,7 @@ describe("TaskDetailModal", () => {
     render(
       <TaskDetailModal
         task={makeTask({ dependencies: [] })}
+        initialTab="definition"
         onClose={noop}
         onMoveTask={noopMove}
         onDeleteTask={noopDelete}
@@ -223,6 +226,7 @@ describe("TaskDetailModal", () => {
     render(
       <TaskDetailModal
         task={makeTask({ dependencies: ["FN-001", "FN-002"] })}
+        initialTab="definition"
         tasks={allTasks}
         onClose={noop}
         onMoveTask={noopMove}
@@ -258,6 +262,7 @@ describe("TaskDetailModal", () => {
     render(
       <TaskDetailModal
         task={makeTask({ dependencies: [] })}
+        initialTab="definition"
         tasks={allTasks}
         onClose={noop}
         onMoveTask={noopMove}
@@ -288,6 +293,7 @@ describe("TaskDetailModal", () => {
     render(
       <TaskDetailModal
         task={makeTask({ dependencies: ["FN-001", "FN-002"] })}
+        initialTab="definition"
         onClose={noop}
         onMoveTask={noopMove}
         onDeleteTask={noopDelete}
@@ -379,6 +385,7 @@ describe("TaskDetailModal", () => {
     render(
       <TaskDetailModal
         task={makeTask({ dependencies: [] })}
+        initialTab="definition"
         tasks={allTasks}
         onClose={noop}
         onMoveTask={noopMove}
@@ -408,6 +415,7 @@ describe("TaskDetailModal", () => {
     render(
       <TaskDetailModal
         task={makeTask({ dependencies: [] })}
+        initialTab="definition"
         tasks={allTasks}
         onClose={noop}
         onMoveTask={noopMove}
@@ -427,7 +435,7 @@ describe("TaskDetailModal", () => {
   });
 
   describe("tab toggle", () => {
-    it("defaults to the Definition tab", () => {
+    it("defaults to the Chat tab", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ prompt: "# Hello\n\nContent" })}
@@ -442,18 +450,19 @@ describe("TaskDetailModal", () => {
 
       expect(screen.getByText("Definition")).toBeTruthy();
       expect(screen.getByText("Logs")).toBeTruthy();
-      // Activity and Agent Log are subviews inside the Logs tab, not top-level tabs
-      // They should NOT be visible on the Definition tab
+      // Activity and Agent Log are subviews inside the Logs tab, not top-level tabs.
+      // They should NOT be visible on the default Chat tab.
       expect(screen.queryByText("Activity")).toBeNull();
       expect(screen.queryByText("Agent Log")).toBeNull();
-      // Definition content should be visible
-      expect(container.querySelector(".markdown-body")).toBeTruthy();
-      // Activity section should NOT be visible initially
+      // Chat content should be visible by default.
+      expect(container.querySelector(".detail-section--chat")).toBeTruthy();
+      expect(container.querySelector("[data-testid='task-chat-tab']")).toBeTruthy();
+      // Activity section should NOT be visible initially.
       expect(container.querySelector(".detail-activity")).toBeNull();
-      // Agent log viewer should not be visible
+      // Agent log viewer should not be visible.
       expect(container.querySelector("[data-testid='agent-log-viewer']")).toBeNull();
 
-      // After clicking Logs tab, the subview toggle buttons should appear
+      // After clicking Logs tab, the subview toggle buttons should appear.
       fireEvent.click(screen.getByText("Logs"));
       const logSubviewToggle = container.querySelector(".log-subview-toggle");
       expect(logSubviewToggle).toBeTruthy();
@@ -601,6 +610,7 @@ describe("TaskDetailModal", () => {
             prompt: "# Hello\n\nContent",
             log: [{ timestamp: "2026-01-01T00:00:00Z", action: "Test" }],
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -691,7 +701,7 @@ describe("TaskDetailModal", () => {
         />,
       );
 
-      // Default: Definition tab active → enabled should be false
+      // Default: Chat tab active → enabled should be false
       const initialCall = mockUseAgentLogs.mock.calls[mockUseAgentLogs.mock.calls.length - 1];
       expect(initialCall[1]).toBe(false);
 
@@ -744,15 +754,15 @@ describe("TaskDetailModal", () => {
       );
 
       // For an in-progress task (no workflow steps, no merge commit), the
-      // top-level tabs are: Definition, Chat, Logs, Changes, Review, Comments,
+      // top-level tabs are: Chat, Definition, Logs, Changes, Review, Comments,
       // Documents, Model, Workflow, Stats, Routing.
-      const tabTexts = ["Definition", "Chat", "Logs", "Changes", "Review", "Comments", "Documents", "Model", "Workflow", "Stats", "Routing"];
+      const tabTexts = ["Chat", "Definition", "Logs", "Changes", "Review", "Comments", "Documents", "Model", "Workflow", "Stats", "Routing"];
       const tabs = screen.getAllByRole("button").filter((b) =>
         tabTexts.includes(b.textContent || "")
       );
       expect(tabs.map((tab) => tab.textContent)).toEqual(tabTexts);
-      expect(tabs[0].textContent).toBe("Definition");
-      expect(tabs[1].textContent).toBe("Chat");
+      expect(tabs[0].textContent).toBe("Chat");
+      expect(tabs[1].textContent).toBe("Definition");
       expect(tabs[2].textContent).toBe("Logs");
 
       // Activity and Agent Log are NOT top-level tabs (they are subviews inside Logs)
@@ -937,6 +947,47 @@ describe("TaskDetailModal", () => {
       expect(screen.queryByTestId("task-chat-expand-toggle")).toBeNull();
     });
 
+    it("FN-6532 defaults to Chat first while preserving explicit tab requests", () => {
+      const { container, rerender } = render(
+        <TaskDetailModal
+          task={makeTask({ prompt: "# Hello\n\nContent" })}
+          onClose={noop}
+          onMoveTask={noopMove}
+          onDeleteTask={noopDelete}
+          onMergeTask={noopMerge}
+          onOpenDetail={noopOpenDetail}
+          addToast={noop}
+        />,
+      );
+
+      const tabs = Array.from(container.querySelectorAll<HTMLButtonElement>(".detail-tab"));
+      expect(tabs.map((tab) => tab.textContent)).toEqual(expect.arrayContaining(["Chat", "Definition"]));
+      expect(tabs[0]).toHaveTextContent("Chat");
+      const chatTab = screen.getByRole("button", { name: "Chat" });
+      const definitionTab = screen.getByRole("button", { name: "Definition" });
+      expect(chatTab.compareDocumentPosition(definitionTab) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+      expect(chatTab).toHaveClass("detail-tab-active");
+      expect(definitionTab).not.toHaveClass("detail-tab-active");
+      expect(container.querySelector(".detail-section--chat [data-testid='task-chat-tab']")).toBeTruthy();
+
+      rerender(
+        <TaskDetailModal
+          task={makeTask({ prompt: "# Hello\n\nContent" })}
+          initialTab="logs"
+          onClose={noop}
+          onMoveTask={noopMove}
+          onDeleteTask={noopDelete}
+          onMergeTask={noopMerge}
+          onOpenDetail={noopOpenDetail}
+          addToast={noop}
+        />,
+      );
+
+      expect(screen.getByRole("button", { name: "Logs" })).toHaveClass("detail-tab-active");
+      expect(screen.getByRole("button", { name: "Chat" })).not.toHaveClass("detail-tab-active");
+      expect(container.querySelector(".detail-section--chat")).toBeNull();
+    });
+
     it("FN-6347 applies chat modifiers only while the Chat tab is active", () => {
       const { container } = render(
         <TaskDetailModal
@@ -950,10 +1001,6 @@ describe("TaskDetailModal", () => {
         />,
       );
 
-      expect(container.querySelector(".detail-body--chat")).toBeNull();
-      expect(container.querySelector(".detail-section--chat")).toBeNull();
-
-      fireEvent.click(screen.getByRole("button", { name: "Chat" }));
       const chatBody = container.querySelector(".detail-body--chat");
       const chatSection = container.querySelector(".detail-section--chat");
       expect(chatBody).toBeTruthy();
diff --git a/packages/dashboard/app/components/__tests__/TaskDetailModal.definition-actions.test.tsx b/packages/dashboard/app/components/__tests__/TaskDetailModal.definition-actions.test.tsx
index 04c15203fd..29b36b7507 100644
--- a/packages/dashboard/app/components/__tests__/TaskDetailModal.definition-actions.test.tsx
+++ b/packages/dashboard/app/components/__tests__/TaskDetailModal.definition-actions.test.tsx
@@ -24,6 +24,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ prompt: "# Test\n\nSpec content." })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -40,6 +41,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ prompt: "# Test\n\nSpec content." })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -65,6 +67,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ prompt: "# Test Task\n\nTest specification." })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -94,6 +97,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ id: "FN-099", prompt: "# Original" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -121,6 +125,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ prompt: "# Test" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -146,6 +151,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-099", column: "todo", prompt: "# Test" })}
+          initialTab="definition"
           onClose={onClose}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -173,6 +179,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask()}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -183,11 +190,11 @@ describe("TaskDetailModal", () => {
       );
 
       // In-progress tasks show exactly 11 tabs:
-      // Definition, Chat, Logs, Changes, Review, Comments, Documents, Model, Workflow, Stats, Routing
+      // Chat, Definition, Logs, Changes, Review, Comments, Documents, Model, Workflow, Stats, Routing
       const tabs = container.querySelectorAll(".detail-tab");
       expect(tabs.length).toBe(11);
-      expect(tabs[0].textContent).toBe("Definition");
-      expect(tabs[1].textContent).toBe("Chat");
+      expect(tabs[0].textContent).toBe("Chat");
+      expect(tabs[1].textContent).toBe("Definition");
       expect(tabs[2].textContent).toBe("Logs");
       expect(tabs[3].textContent).toBe("Changes");
       expect(tabs[4].textContent).toBe("Review");
@@ -205,6 +212,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ enabledWorkflowSteps: ["WS-001"] })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -217,8 +225,8 @@ describe("TaskDetailModal", () => {
       // In-progress task with workflow steps: 11 tabs (Review after Changes, Workflow after Model)
       const tabs = container.querySelectorAll(".detail-tab");
       expect(tabs.length).toBe(11);
-      expect(tabs[0].textContent).toBe("Definition");
-      expect(tabs[1].textContent).toBe("Chat");
+      expect(tabs[0].textContent).toBe("Chat");
+      expect(tabs[1].textContent).toBe("Definition");
       expect(tabs[2].textContent).toBe("Logs");
       expect(tabs[3].textContent).toBe("Changes");
       expect(tabs[4].textContent).toBe("Review");
@@ -237,6 +245,7 @@ describe("TaskDetailModal", () => {
             column: "done",
             mergeDetails: { commitSha: "abc1234567890", filesChanged: 3 },
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -246,11 +255,11 @@ describe("TaskDetailModal", () => {
         />,
       );
 
-      // Done task with commit SHA: Definition, Chat, Logs, Changes, Review, Comments, Documents, Model, Workflow, Stats, Routing (11 tabs, no Commits)
+      // Done task with commit SHA: Chat, Definition, Logs, Changes, Review, Comments, Documents, Model, Workflow, Stats, Routing (11 tabs, no Commits)
       const tabs = container.querySelectorAll(".detail-tab");
       expect(tabs.length).toBe(11);
-      expect(tabs[0].textContent).toBe("Definition");
-      expect(tabs[1].textContent).toBe("Chat");
+      expect(tabs[0].textContent).toBe("Chat");
+      expect(tabs[1].textContent).toBe("Definition");
       expect(tabs[2].textContent).toBe("Logs");
       expect(tabs[3].textContent).toBe("Changes");
       expect(tabs[4].textContent).toBe("Review");
@@ -272,6 +281,7 @@ describe("TaskDetailModal", () => {
             mergeDetails: { commitSha: "abc1234567890", filesChanged: 3 },
             enabledWorkflowSteps: ["WS-001"],
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -284,8 +294,8 @@ describe("TaskDetailModal", () => {
       // Done task with workflow steps and commit SHA: 11 tabs including Review (no Commits)
       const tabs = container.querySelectorAll(".detail-tab");
       expect(tabs.length).toBe(11);
-      expect(tabs[0].textContent).toBe("Definition");
-      expect(tabs[1].textContent).toBe("Chat");
+      expect(tabs[0].textContent).toBe("Chat");
+      expect(tabs[1].textContent).toBe("Definition");
       expect(tabs[2].textContent).toBe("Logs");
       expect(tabs[3].textContent).toBe("Changes");
       expect(tabs[4].textContent).toBe("Review");
@@ -303,6 +313,7 @@ describe("TaskDetailModal", () => {
       const { container: triageContainer } = render(
         <TaskDetailModal
           task={makeTask({ column: "triage" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -313,14 +324,15 @@ describe("TaskDetailModal", () => {
       );
 
       const triageTabs = triageContainer.querySelectorAll(".detail-tab");
-      expect(triageTabs.length).toBe(10); // Definition, Chat, Logs, Review, Comments, Documents, Model, Workflow, Stats, Routing
+      expect(triageTabs.length).toBe(10); // Chat, Definition, Logs, Review, Comments, Documents, Model, Workflow, Stats, Routing
       expect(Array.from(triageTabs).map(t => t.textContent)).toEqual([
-        "Definition", "Chat", "Logs", "Review", "Comments", "Documents", "Model", "Workflow", "Stats", "Routing",
+        "Chat", "Definition", "Logs", "Review", "Comments", "Documents", "Model", "Workflow", "Stats", "Routing",
       ]);
 
       const { container: todoContainer } = render(
         <TaskDetailModal
           task={makeTask({ column: "todo" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -331,9 +343,9 @@ describe("TaskDetailModal", () => {
       );
 
       const todoTabs = todoContainer.querySelectorAll(".detail-tab");
-      expect(todoTabs.length).toBe(10); // Definition, Chat, Logs, Review, Comments, Documents, Model, Workflow, Stats, Routing
+      expect(todoTabs.length).toBe(10); // Chat, Definition, Logs, Review, Comments, Documents, Model, Workflow, Stats, Routing
       expect(Array.from(todoTabs).map(t => t.textContent)).toEqual([
-        "Definition", "Chat", "Logs", "Review", "Comments", "Documents", "Model", "Workflow", "Stats", "Routing",
+        "Chat", "Definition", "Logs", "Review", "Comments", "Documents", "Model", "Workflow", "Stats", "Routing",
       ]);
     });
 
@@ -341,6 +353,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ prompt: "" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -364,6 +377,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -385,6 +399,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -406,6 +421,7 @@ describe("TaskDetailModal", () => {
             status: "planning",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -427,6 +443,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -454,6 +471,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={onClose}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -489,6 +507,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={onClose}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -534,6 +553,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -566,6 +586,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -600,6 +621,7 @@ describe("TaskDetailModal", () => {
             status: "awaiting-approval",
             prompt: "# Task Spec",
           })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -623,6 +645,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask()}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -644,6 +667,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask()}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -665,6 +689,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -697,6 +722,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001" })}
+          initialTab="definition"
           onClose={onClose}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -729,6 +755,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -759,6 +786,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -788,6 +816,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -821,6 +850,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -839,6 +869,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column: "triage" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -854,6 +885,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column: "triage", paused: true })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -870,6 +902,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column: "triage", paused: true })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -891,6 +924,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "todo", paused: undefined, userPaused: true })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -917,6 +951,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column: "triage", paused: true, assignedAgentId: "agent-1" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -946,6 +981,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column: "triage", paused: true, assignedAgentId: "agent-1", pausedByAgentId: "agent-1" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -968,6 +1004,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ column: "triage", paused: false, status: "todo" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -984,6 +1021,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1007,6 +1045,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1029,6 +1068,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1056,6 +1096,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1079,6 +1120,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1109,6 +1151,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={onClose}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1136,6 +1179,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1168,6 +1212,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={onClose}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1204,6 +1249,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1234,6 +1280,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1267,6 +1314,7 @@ describe("TaskDetailModal", () => {
       render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
@@ -1300,6 +1348,7 @@ describe("TaskDetailModal", () => {
       const { container } = render(
         <TaskDetailModal
           task={makeTask({ id: "FN-001", column: "done" })}
+          initialTab="definition"
           onClose={noop}
           onMoveTask={noopMove}
           onDeleteTask={noopDelete}
diff --git a/packages/dashboard/app/hooks/__tests__/useModalManager.test.ts b/packages/dashboard/app/hooks/__tests__/useModalManager.test.ts
index 04fcb5e711..e2b90a31a2 100644
--- a/packages/dashboard/app/hooks/__tests__/useModalManager.test.ts
+++ b/packages/dashboard/app/hooks/__tests__/useModalManager.test.ts
@@ -132,7 +132,7 @@ describe("useModalManager", () => {
     });
 
     expect(result.current.detailTask?.id).toBe("FN-123");
-    expect(result.current.detailTaskInitialTab).toBe("definition");
+    expect(result.current.detailTaskInitialTab).toBe("chat");
 
     act(() => {
       result.current.openDetailWithChangesTab(task);
@@ -203,7 +203,7 @@ describe("useModalManager", () => {
     expect(result.current.detailTask?.id).toBe("FN-456");
     // Should not have prompt field (plain Task)
     expect("prompt" in (result.current.detailTask as unknown as Record<string, unknown>)).toBe(false);
-    expect(result.current.detailTaskInitialTab).toBe("definition");
+    expect(result.current.detailTaskInitialTab).toBe("chat");
   });
 
   it.each([
diff --git a/packages/dashboard/app/hooks/useModalManager.ts b/packages/dashboard/app/hooks/useModalManager.ts
index 924a46a45e..28a4d1f754 100644
--- a/packages/dashboard/app/hooks/useModalManager.ts
+++ b/packages/dashboard/app/hooks/useModalManager.ts
@@ -5,6 +5,7 @@ import type { SectionId } from "../components/SettingsModal";
 import type { ToastType } from "./useToast";
 
 export type DetailTaskTab =
+  | "chat"
   | "definition"
   | "logs"
   | "changes"
@@ -162,7 +163,11 @@ export function useModalManager(options: UseModalManagerOptions): ModalManager {
   const [subtaskResumeSessionId, setSubtaskResumeSessionId] = useState<string | undefined>(undefined);
   // Can be Task (optimistic open) or TaskDetail (full data with prompt)
   const [detailTask, setDetailTask] = useState<(Task | TaskDetail) | null>(null);
-  const [detailTaskInitialTab, setDetailTaskInitialTab] = useState<DetailTaskTab>("definition");
+  /**
+   * FNXC:TaskDetailTabs 2026-06-17-00:00:
+   * FN-6532 makes Chat the default task-detail view whenever a task opens without an explicit tab request.
+   */
+  const [detailTaskInitialTab, setDetailTaskInitialTab] = useState<DetailTaskTab>("chat");
   const [detailTaskOrigin, setDetailTaskOrigin] = useState<DetailTaskOrigin | null>(null);
   const [groupModalGroupId, setGroupModalGroupId] = useState<string | null>(null);
   const [settingsOpen, setSettingsOpen] = useState(false);
@@ -250,9 +255,13 @@ export function useModalManager(options: UseModalManagerOptions): ModalManager {
     setSubtaskResumeSessionId(undefined);
   }, []);
 
+  /**
+   * FNXC:TaskDetailTabs 2026-06-17-00:00:
+   * Open-detail callers that omit initialTab should land on Chat; explicit tab requests preserve caller intent.
+   */
   const openDetailTask = useCallback((
     task: Task | TaskDetail,
-    initialTab: DetailTaskTab = "definition",
+    initialTab: DetailTaskTab = "chat",
     options?: { origin?: DetailTaskOrigin },
   ) => {
     setDetailTask(task);