feat: track line changes for delegated subtasks

Compute per-task lines added/removed from tool diffStats, persist on history items, and aggregate recursively across descendants.\n\nRender +/− in todo rows, task header, and expanded task details with diff-like green/red styling. Update i18n labels across locales and adjust layout/alignment.\n\nRelates to PR #10765

packages/types/src/history.ts

@@ -16,6 +16,8 @@ export const historyItemSchema = z.object({
 	cacheWrites: z.number().optional(),
 	cacheReads: z.number().optional(),
 	totalCost: z.number(),
+	linesAdded: z.number().optional(),
+	linesRemoved: z.number().optional(),
 	size: z.number().optional(),
 	workspace: z.string().optional(),
 	mode: z.string().optional(),

packages/types/src/todo.ts

@@ -18,6 +18,8 @@ export const todoItemSchema = z.object({
 	subtaskId: z.string().optional(), // ID of the linked subtask (child task) for direct cost/token attribution
 	tokens: z.number().optional(), // Total tokens (in + out) for linked subtask
 	cost: z.number().optional(), // Total cost for linked subtask
+	added: z.number().optional(),
+	removed: z.number().optional(),
 })
 
 export type TodoItem = z.infer<typeof todoItemSchema>

src/core/task-persistence/__tests__/taskMetadata.spec.ts

@@ -0,0 +1,125 @@
+import { describe, it, expect, vi, beforeEach } from "vitest"
+
+// Hoisted mocks to avoid initialization ordering issues
+const hoisted = vi.hoisted(() => ({
+	getTaskDirectoryPathMock: vi.fn().mockResolvedValue("/mock/task/dir"),
+	getFolderSizeLooseMock: vi.fn().mockResolvedValue(0),
+	getApiMetricsMock: vi.fn().mockReturnValue({
+		totalTokensIn: 0,
+		totalTokensOut: 0,
+		totalCacheWrites: 0,
+		totalCacheReads: 0,
+		totalCost: 0,
+		contextTokens: 0,
+	}),
+}))
+
+vi.mock("get-folder-size", () => ({
+	default: {
+		loose: hoisted.getFolderSizeLooseMock,
+	},
+}))
+
+vi.mock("../../../utils/storage", () => ({
+	getTaskDirectoryPath: hoisted.getTaskDirectoryPathMock,
+}))
+
+vi.mock("../../../shared/getApiMetrics", () => ({
+	getApiMetrics: hoisted.getApiMetricsMock,
+}))
+
+// Import after mocks
+import { taskMetadata } from "../taskMetadata"
+
+describe("taskMetadata() line change parsing", () => {
+	beforeEach(() => {
+		hoisted.getTaskDirectoryPathMock.mockClear()
+		hoisted.getFolderSizeLooseMock.mockClear()
+		hoisted.getApiMetricsMock.mockClear()
+	})
+
+	it("computes linesAdded/linesRemoved from tool message diffStats", async () => {
+		const result = await taskMetadata({
+			taskId: "task-1",
+			taskNumber: 1,
+			globalStoragePath: "/mock/global",
+			workspace: "/mock/workspace",
+			messages: [
+				{ ts: 1, type: "say", say: "text", text: "Task" } as any,
+				{
+					ts: 2,
+					type: "ask",
+					ask: "tool",
+					text: JSON.stringify({ diffStats: { added: 5, removed: 2 } }),
+				} as any,
+			],
+		})
+
+		expect(result.historyItem.linesAdded).toBe(5)
+		expect(result.historyItem.linesRemoved).toBe(2)
+	})
+
+	it("aggregates linesAdded/linesRemoved from batch tool message batchDiffs[].diffStats", async () => {
+		const result = await taskMetadata({
+			taskId: "task-2",
+			taskNumber: 2,
+			globalStoragePath: "/mock/global",
+			workspace: "/mock/workspace",
+			messages: [
+				{ ts: 1, type: "say", say: "text", text: "Task" } as any,
+				{
+					ts: 2,
+					type: "ask",
+					ask: "tool",
+					text: JSON.stringify({
+						batchDiffs: [
+							{ path: "a.ts", diffStats: { added: 1, removed: 1 } },
+							{ path: "b.ts", diffStats: { added: 2, removed: 3 } },
+						],
+					}),
+				} as any,
+			],
+		})
+
+		expect(result.historyItem.linesAdded).toBe(3)
+		expect(result.historyItem.linesRemoved).toBe(4)
+	})
+
+	it("ignores partial tool messages", async () => {
+		const result = await taskMetadata({
+			taskId: "task-3",
+			taskNumber: 3,
+			globalStoragePath: "/mock/global",
+			workspace: "/mock/workspace",
+			messages: [
+				{ ts: 1, type: "say", say: "text", text: "Task" } as any,
+				{
+					ts: 2,
+					type: "ask",
+					ask: "tool",
+					partial: true,
+					text: JSON.stringify({ diffStats: { added: 10, removed: 10 } }),
+				} as any,
+			],
+		})
+
+		expect(result.historyItem.linesAdded).toBeUndefined()
+		expect(result.historyItem.linesRemoved).toBeUndefined()
+	})
+
+	it("ignores invalid JSON in tool message text gracefully", async () => {
+		const result = await taskMetadata({
+			taskId: "task-4",
+			taskNumber: 4,
+			globalStoragePath: "/mock/global",
+			workspace: "/mock/workspace",
+			messages: [
+				{ ts: 1, type: "say", say: "text", text: "Task" } as any,
+				{ ts: 2, type: "ask", ask: "tool", text: "{not-json" } as any,
+			],
+		})
+
+		expect(result.historyItem.linesAdded).toBeUndefined()
+		expect(result.historyItem.linesRemoved).toBeUndefined()
+	})
+})

src/core/task-persistence/taskMetadata.ts

@@ -12,6 +12,64 @@ import { t } from "../../i18n"
 
 const taskSizeCache = new NodeCache({ stdTTL: 30, checkperiod: 5 * 60 })
 
+type DiffStats = { added: number; removed: number }
+
+function isFiniteNumber(value: unknown): value is number {
+	return typeof value === "number" && Number.isFinite(value)
+}
+
+function isDiffStats(value: unknown): value is DiffStats {
+	if (!value || typeof value !== "object") return false
+
+	const v = value as { added?: unknown; removed?: unknown }
+	return isFiniteNumber(v.added) && isFiniteNumber(v.removed)
+}
+
+function getLineStatsFromToolApprovalMessages(messages: ClineMessage[]): {
+	linesAdded: number
+	linesRemoved: number
+	foundAnyStats: boolean
+} {
+	let linesAdded = 0
+	let linesRemoved = 0
+	let foundAnyStats = false
+
+	for (const m of messages) {
+		// Only count complete tool approval asks (avoid double-counting partial/streaming updates)
+		if (!(m.type === "ask" && m.ask === "tool" && m.partial !== true)) continue
+		if (typeof m.text !== "string" || m.text.length === 0) continue
+
+		let payload: unknown
+		try {
+			payload = JSON.parse(m.text)
+		} catch {
+			continue
+		}
+
+		if (!payload || typeof payload !== "object") continue
+		const p = payload as { diffStats?: unknown; batchDiffs?: unknown }
+
+		if (isDiffStats(p.diffStats)) {
+			linesAdded += p.diffStats.added
+			linesRemoved += p.diffStats.removed
+			foundAnyStats = true
+		}
+
+		if (Array.isArray(p.batchDiffs)) {
+			for (const batchDiff of p.batchDiffs) {
+				if (!batchDiff || typeof batchDiff !== "object") continue
+				const bd = batchDiff as { diffStats?: unknown }
+				if (!isDiffStats(bd.diffStats)) continue
+				linesAdded += bd.diffStats.added
+				linesRemoved += bd.diffStats.removed
+				foundAnyStats = true
+			}
+		}
+	}
+
+	return { linesAdded, linesRemoved, foundAnyStats }
+}
+
 export type TaskMetadataOptions = {
 	taskId: string
 	rootTaskId?: string
@@ -55,6 +113,8 @@ export async function taskMetadata({
 	let tokenUsage: ReturnType<typeof getApiMetrics>
 	let taskDirSize: number
 	let taskMessage: ClineMessage | undefined
+	let linesAdded: number | undefined
+	let linesRemoved: number | undefined
 
 	if (!hasMessages) {
 		// Handle no messages case
@@ -93,6 +153,12 @@ export async function taskMetadata({
 		} else {
 			taskDirSize = cachedSize
 		}
+
+		const lineStats = getLineStatsFromToolApprovalMessages(messages)
+		if (lineStats.foundAnyStats) {
+			linesAdded = lineStats.linesAdded
+			linesRemoved = lineStats.linesRemoved
+		}
 	}
 
 	// Create historyItem once with pre-calculated values.
@@ -115,6 +181,8 @@ export async function taskMetadata({
 		cacheWrites: tokenUsage.totalCacheWrites,
 		cacheReads: tokenUsage.totalCacheReads,
 		totalCost: tokenUsage.totalCost,
+		...(typeof linesAdded === "number" ? { linesAdded } : {}),
+		...(typeof linesRemoved === "number" ? { linesRemoved } : {}),
 		size: taskDirSize,
 		workspace,
 		mode,

src/core/webview/ClineProvider.ts

@@ -3372,6 +3372,8 @@ export class ClineProvider
 				if (linkedTodo) {
 					linkedTodo.tokens = (childHistoryItem?.tokensIn || 0) + (childHistoryItem?.tokensOut || 0)
 					linkedTodo.cost = childHistoryItem?.totalCost || 0
+					linkedTodo.added = childHistoryItem?.linesAdded || 0
+					linkedTodo.removed = childHistoryItem?.linesRemoved || 0
 
 					parentClineMessages.push({
 						ts: Date.now(),

src/core/webview/__tests__/aggregateTaskCosts.spec.ts

@@ -53,11 +53,15 @@ describe("aggregateTaskCostsRecursive", () => {
 			parent: {
 				id: "parent",
 				totalCost: 1.0,
+				linesAdded: 2,
+				linesRemoved: 1,
 				childIds: ["child-1"],
 			} as unknown as HistoryItem,
 			"child-1": {
 				id: "child-1",
 				totalCost: 0.5,
+				linesAdded: 3,
+				linesRemoved: 2,
 				childIds: [],
 			} as unknown as HistoryItem,
 		}
@@ -69,6 +73,12 @@ describe("aggregateTaskCostsRecursive", () => {
 		expect(result.ownCost).toBe(1.0)
 		expect(result.childrenCost).toBe(0.5)
 		expect(result.totalCost).toBe(1.5)
+		expect(result.ownAdded).toBe(2)
+		expect(result.ownRemoved).toBe(1)
+		expect(result.childrenAdded).toBe(3)
+		expect(result.childrenRemoved).toBe(2)
+		expect(result.totalAdded).toBe(5)
+		expect(result.totalRemoved).toBe(3)
 		expect(result.childBreakdown).toHaveProperty("child-1")
 		const child1 = result.childBreakdown?.["child-1"]
 		expect(child1).toBeDefined()
@@ -114,16 +124,22 @@ describe("aggregateTaskCostsRecursive", () => {
 			parent: {
 				id: "parent",
 				totalCost: 1.0,
+				linesAdded: 2,
+				linesRemoved: 2,
 				childIds: ["child"],
 			} as unknown as HistoryItem,
 			child: {
 				id: "child",
 				totalCost: 0.5,
+				linesAdded: 3,
+				linesRemoved: 1,
 				childIds: ["grandchild"],
 			} as unknown as HistoryItem,
 			grandchild: {
 				id: "grandchild",
 				totalCost: 0.25,
+				linesAdded: 1,
+				linesRemoved: 4,
 				childIds: [],
 			} as unknown as HistoryItem,
 		}
@@ -136,12 +152,22 @@ describe("aggregateTaskCostsRecursive", () => {
 		expect(result.childrenCost).toBe(0.75) // child (0.5) + grandchild (0.25)
 		expect(result.totalCost).toBe(1.75)
 
+		expect(result.ownAdded).toBe(2)
+		expect(result.ownRemoved).toBe(2)
+		// children totals include all descendants
+		expect(result.childrenAdded).toBe(4) // child (3) + grandchild (1)
+		expect(result.childrenRemoved).toBe(5) // child (1) + grandchild (4)
+		expect(result.totalAdded).toBe(6)
+		expect(result.totalRemoved).toBe(7)
+
 		// Verify child breakdown
 		const child = result.childBreakdown?.["child"]
 		expect(child).toBeDefined()
 		expect(child!.ownCost).toBe(0.5)
 		expect(child!.childrenCost).toBe(0.25)
 		expect(child!.totalCost).toBe(0.75)
+		expect(child!.totalAdded).toBe(4)
+		expect(child!.totalRemoved).toBe(5)
 
 		// Verify grandchild breakdown
 		const grandchild = child!.childBreakdown?.["grandchild"]
@@ -149,6 +175,8 @@ describe("aggregateTaskCostsRecursive", () => {
 		expect(grandchild!.ownCost).toBe(0.25)
 		expect(grandchild!.childrenCost).toBe(0)
 		expect(grandchild!.totalCost).toBe(0.25)
+		expect(grandchild!.totalAdded).toBe(1)
+		expect(grandchild!.totalRemoved).toBe(4)
 	})
 
 	it("should detect and prevent circular references", async () => {
@@ -156,11 +184,15 @@ describe("aggregateTaskCostsRecursive", () => {
 			"task-a": {
 				id: "task-a",
 				totalCost: 1.0,
+				linesAdded: 2,
+				linesRemoved: 3,
 				childIds: ["task-b"],
 			} as unknown as HistoryItem,
 			"task-b": {
 				id: "task-b",
 				totalCost: 0.5,
+				linesAdded: 4,
+				linesRemoved: 1,
 				childIds: ["task-a"], // Circular reference back to task-a
 			} as unknown as HistoryItem,
 		}
@@ -173,6 +205,8 @@ describe("aggregateTaskCostsRecursive", () => {
 		expect(result.ownCost).toBe(1.0)
 		expect(result.childrenCost).toBe(0.5) // Only task-b's own cost, circular ref returns 0
 		expect(result.totalCost).toBe(1.5)
+		expect(result.totalAdded).toBe(6) // task-a (2) + task-b (4)
+		expect(result.totalRemoved).toBe(4) // task-a (3) + task-b (1)
 
 		// Verify warning was logged
 		expect(consoleWarnSpy).toHaveBeenCalledWith(expect.stringContaining("Circular reference detected: task-a"))
@@ -333,11 +367,23 @@ describe("buildSubtaskDetails", () => {
 				ownCost: 0.5,
 				childrenCost: 0,
 				totalCost: 0.5,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 10,
+				totalRemoved: 5,
 			},
 			"child-2": {
 				ownCost: 0.3,
 				childrenCost: 0.2,
 				totalCost: 0.5,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 1,
+				totalRemoved: 2,
 			},
 		}
 
@@ -369,6 +415,8 @@ describe("buildSubtaskDetails", () => {
 		expect(child1!.name).toBe("First subtask")
 		expect(child1!.tokens).toBe(150) // 100 + 50
 		expect(child1!.cost).toBe(0.5)
+		expect(child1!.added).toBe(10)
+		expect(child1!.removed).toBe(5)
 		expect(child1!.status).toBe("completed")
 		expect(child1!.hasNestedChildren).toBe(false)
 
@@ -377,6 +425,8 @@ describe("buildSubtaskDetails", () => {
 		expect(child2!.name).toBe("Second subtask with nested children")
 		expect(child2!.tokens).toBe(300) // 200 + 100
 		expect(child2!.cost).toBe(0.5)
+		expect(child2!.added).toBe(1)
+		expect(child2!.removed).toBe(2)
 		expect(child2!.status).toBe("active")
 		expect(child2!.hasNestedChildren).toBe(true) // childrenCost > 0
 	})
@@ -389,6 +439,12 @@ describe("buildSubtaskDetails", () => {
 				ownCost: 1.0,
 				childrenCost: 0,
 				totalCost: 1.0,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 0,
+				totalRemoved: 0,
 			},
 		}
 
@@ -418,6 +474,12 @@ describe("buildSubtaskDetails", () => {
 				ownCost: 1.0,
 				childrenCost: 0,
 				totalCost: 1.0,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 0,
+				totalRemoved: 0,
 			},
 		}
 
@@ -445,11 +507,23 @@ describe("buildSubtaskDetails", () => {
 				ownCost: 0.5,
 				childrenCost: 0,
 				totalCost: 0.5,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 0,
+				totalRemoved: 0,
 			},
 			"missing-child": {
 				ownCost: 0.3,
 				childrenCost: 0,
 				totalCost: 0.3,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 0,
+				totalRemoved: 0,
 			},
 		}
 
@@ -488,6 +562,12 @@ describe("buildSubtaskDetails", () => {
 				ownCost: 0.5,
 				childrenCost: 0,
 				totalCost: 0.5,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 0,
+				totalRemoved: 0,
 			},
 		}
 
@@ -514,6 +594,12 @@ describe("buildSubtaskDetails", () => {
 				ownCost: 0.5,
 				childrenCost: 0,
 				totalCost: 0.5,
+				ownAdded: 0,
+				ownRemoved: 0,
+				childrenAdded: 0,
+				childrenRemoved: 0,
+				totalAdded: 0,
+				totalRemoved: 0,
 			},
 		}
 

src/core/webview/aggregateTaskCosts.ts

@@ -8,6 +8,8 @@ export interface SubtaskDetail {
 	name: string // First 50 chars of task description
 	tokens: number // tokensIn + tokensOut
 	cost: number // Aggregated total cost
+	added: number // Aggregated total lines added
+	removed: number // Aggregated total lines removed
 	status: "active" | "completed" | "delegated"
 	hasNestedChildren: boolean // Has its own subtasks
 }
@@ -16,6 +18,12 @@ export interface AggregatedCosts {
 	ownCost: number // This task's own API costs
 	childrenCost: number // Sum of all direct children costs (recursive)
 	totalCost: number // ownCost + childrenCost
+	ownAdded: number // This task's own lines added
+	ownRemoved: number // This task's own lines removed
+	childrenAdded: number // Sum of all descendant lines added
+	childrenRemoved: number // Sum of all descendant lines removed
+	totalAdded: number // ownAdded + childrenAdded
+	totalRemoved: number // ownRemoved + childrenRemoved
 	childBreakdown?: {
 		// Optional detailed breakdown
 		[childId: string]: AggregatedCosts
@@ -39,7 +47,17 @@ export async function aggregateTaskCostsRecursive(
 	// Prevent infinite loops
 	if (visited.has(taskId)) {
 		console.warn(`[aggregateTaskCostsRecursive] Circular reference detected: ${taskId}`)
-		return { ownCost: 0, childrenCost: 0, totalCost: 0 }
+		return {
+			ownCost: 0,
+			childrenCost: 0,
+			totalCost: 0,
+			ownAdded: 0,
+			ownRemoved: 0,
+			childrenAdded: 0,
+			childrenRemoved: 0,
+			totalAdded: 0,
+			totalRemoved: 0,
+		}
 	}
 	visited.add(taskId)
 
@@ -47,11 +65,25 @@ export async function aggregateTaskCostsRecursive(
 	const history = await getTaskHistory(taskId)
 	if (!history) {
 		console.warn(`[aggregateTaskCostsRecursive] Task ${taskId} not found`)
-		return { ownCost: 0, childrenCost: 0, totalCost: 0 }
+		return {
+			ownCost: 0,
+			childrenCost: 0,
+			totalCost: 0,
+			ownAdded: 0,
+			ownRemoved: 0,
+			childrenAdded: 0,
+			childrenRemoved: 0,
+			totalAdded: 0,
+			totalRemoved: 0,
+		}
 	}
 
 	const ownCost = history.totalCost || 0
+	const ownAdded = history.linesAdded || 0
+	const ownRemoved = history.linesRemoved || 0
 	let childrenCost = 0
+	let childrenAdded = 0
+	let childrenRemoved = 0
 	const childBreakdown: { [childId: string]: AggregatedCosts } = {}
 
 	// Recursively aggregate child costs
@@ -63,6 +95,8 @@ export async function aggregateTaskCostsRecursive(
 				new Set(visited), // Create new Set to allow sibling traversal
 			)
 			childrenCost += childAggregated.totalCost
+			childrenAdded += childAggregated.totalAdded
+			childrenRemoved += childAggregated.totalRemoved
 			childBreakdown[childId] = childAggregated
 		}
 	}
@@ -71,6 +105,12 @@ export async function aggregateTaskCostsRecursive(
 		ownCost,
 		childrenCost,
 		totalCost: ownCost + childrenCost,
+		ownAdded,
+		ownRemoved,
+		childrenAdded,
+		childrenRemoved,
+		totalAdded: ownAdded + childrenAdded,
+		totalRemoved: ownRemoved + childrenRemoved,
 		childBreakdown,
 	}
 
@@ -104,6 +144,8 @@ export async function buildSubtaskDetails(
 				name: truncateTaskName(history.task, 50),
 				tokens: (history.tokensIn || 0) + (history.tokensOut || 0),
 				cost: costs.totalCost,
+				added: costs.totalAdded,
+				removed: costs.totalRemoved,
 				status: history.status || "completed",
 				hasNestedChildren: costs.childrenCost > 0,
 			})

webview-ui/src/components/chat/TaskHeader.tsx

@@ -85,7 +85,7 @@ const TaskHeader = ({
 			? (() => {
 					const lastRelevantIndex = findLastIndex(
 						clineMessages,
-						(m) => !(m.ask === "resume_task" || m.ask === "resume_completed_task"),
+						(m) => !((m as any)?.ask === "resume_task" || (m as any)?.ask === "resume_completed_task"),
 					)
 					return lastRelevantIndex !== -1
 						? clineMessages[lastRelevantIndex]?.ask === "completion_result"
@@ -160,6 +160,50 @@ const TaskHeader = ({
 		return costs
 	}, [todos, subtaskDetails])
 
+	const aggregatedLineChanges = useMemo(() => {
+		const ownAdded = (currentTaskItem as any)?.linesAdded
+		const ownRemoved = (currentTaskItem as any)?.linesRemoved
+
+		const processedSubtasks = new Set<string>()
+		let childrenAdded = 0
+		let childrenRemoved = 0
+
+		if (Array.isArray(subtaskDetails)) {
+			for (const subtask of subtaskDetails) {
+				if (!subtask?.id || typeof subtask.id !== "string") continue
+				if (processedSubtasks.has(subtask.id)) continue
+				processedSubtasks.add(subtask.id)
+
+				if (typeof subtask.added === "number" && Number.isFinite(subtask.added)) {
+					childrenAdded += subtask.added
+				}
+				if (typeof subtask.removed === "number" && Number.isFinite(subtask.removed)) {
+					childrenRemoved += subtask.removed
+				}
+			}
+		}
+
+		const totalAdded = (typeof ownAdded === "number" && Number.isFinite(ownAdded) ? ownAdded : 0) + childrenAdded
+		const totalRemoved =
+			(typeof ownRemoved === "number" && Number.isFinite(ownRemoved) ? ownRemoved : 0) + childrenRemoved
+
+		const hasAdded = totalAdded > 0
+		const hasRemoved = totalRemoved > 0
+		const hasAnyLineChanges = hasAdded || hasRemoved
+		const formatted = [hasAdded ? `+${totalAdded}` : null, hasRemoved ? `−${totalRemoved}` : null]
+			.filter(Boolean)
+			.join(" ")
+
+		return {
+			totalAdded,
+			totalRemoved,
+			hasAdded,
+			hasRemoved,
+			hasAnyLineChanges,
+			formatted,
+		}
+	}, [currentTaskItem, subtaskDetails])
+
 	const tooltipCostData = useMemo(
 		() =>
 			getTaskHeaderCostTooltipData({
@@ -313,7 +357,7 @@ const TaskHeader = ({
 								<StandardTooltip
 									content={
 										shouldTreatAsHasSubtasks ? (
-											<div>
+											<div className="space-y-1">
 												<div>
 													{t("chat:costs.totalWithSubtasks", {
 														cost: displayTotalCost.toFixed(2),
@@ -329,7 +373,7 @@ const TaskHeader = ({
 									}
 									side="top"
 									sideOffset={8}>
-									<span>
+									<span className="tabular-nums">
 										${displayTotalCost.toFixed(2)}
 										{shouldTreatAsHasSubtasks && (
 											<span className="text-xs ml-1" title={t("chat:costs.includesSubtasks")}>
@@ -339,6 +383,20 @@ const TaskHeader = ({
 									</span>
 								</StandardTooltip>
 							)}
+							{aggregatedLineChanges.hasAnyLineChanges && (
+								<span className="flex items-center gap-2 tabular-nums text-sm">
+									{aggregatedLineChanges.hasAdded && (
+										<span className="font-medium text-vscode-charts-green">
+											+{aggregatedLineChanges.totalAdded}
+										</span>
+									)}
+									{aggregatedLineChanges.hasRemoved && (
+										<span className="font-medium text-vscode-charts-red">
+											−{aggregatedLineChanges.totalRemoved}
+										</span>
+									)}
+								</span>
+							)}
 						</div>
 						{showBrowserGlobe && (
 							<div className="flex items-center gap-1" onClick={(e) => e.stopPropagation()}>
@@ -514,6 +572,28 @@ const TaskHeader = ({
 										</tr>
 									)}
 
+									{aggregatedLineChanges.hasAnyLineChanges && (
+										<tr>
+											<th className="font-medium text-left align-top w-1 whitespace-nowrap pr-3 h-[24px]">
+												{t("common:stats.lines")}
+											</th>
+											<td className="font-light align-top">
+												<span className="flex items-center gap-2 tabular-nums">
+													{aggregatedLineChanges.hasAdded && (
+														<span className="font-medium text-vscode-charts-green">
+															+{aggregatedLineChanges.totalAdded}
+														</span>
+													)}
+													{aggregatedLineChanges.hasRemoved && (
+														<span className="font-medium text-vscode-charts-red">
+															−{aggregatedLineChanges.totalRemoved}
+														</span>
+													)}
+												</span>
+											</td>
+										</tr>
+									)}
+
 									{/* Size display */}
 									{!!currentTaskItem?.size && currentTaskItem.size > 0 && (
 										<tr>

webview-ui/src/components/chat/TodoListDisplay.tsx

@@ -19,6 +19,8 @@ interface TodoItem {
 	subtaskId?: string
 	tokens?: number
 	cost?: number
+	added?: number
+	removed?: number
 }
 
 function getTodoIcon(status: TodoStatus | null) {
@@ -84,7 +86,7 @@ export function TodoListDisplay({ todos, subtaskDetails, onSubtaskClick }: TodoL
 						? "text-vscode-charts-yellow"
 						: "text-vscode-foreground",
 				)}
-				onClick={() => setIsCollapsed((v) => !v)}>
+				onClick={() => setIsCollapsed((v: boolean) => !v)}>
 				<ListChecks className="size-3 shrink-0" />
 				<span className="flex-1 overflow-hidden text-ellipsis whitespace-nowrap">
 					{isCollapsed
@@ -113,6 +115,17 @@ export function TodoListDisplay({ todos, subtaskDetails, onSubtaskClick }: TodoL
 						const displayCost = todo.cost ?? subtaskById?.cost
 						const shouldShowCost = typeof displayTokens === "number" && typeof displayCost === "number"
 
+						const displayAdded = todo.added ?? subtaskById?.added
+						const displayRemoved = todo.removed ?? subtaskById?.removed
+						const hasValidSubtaskLink = typeof todo.subtaskId === "string" && todo.subtaskId.length > 0
+						const shouldShowLineChanges =
+							hasValidSubtaskLink && (Number.isFinite(displayAdded) || Number.isFinite(displayRemoved))
+
+						const hasAdded =
+							typeof displayAdded === "number" && Number.isFinite(displayAdded) && displayAdded > 0
+						const hasRemoved =
+							typeof displayRemoved === "number" && Number.isFinite(displayRemoved) && displayRemoved > 0
+
 						return (
 							<li
 								key={todo.id || todo.content}
@@ -131,14 +144,36 @@ export function TodoListDisplay({ todos, subtaskDetails, onSubtaskClick }: TodoL
 									{todo.content}
 								</span>
 								{/* Token count and cost display */}
-								{shouldShowCost && (
+								{(shouldShowCost || shouldShowLineChanges) && (
 									<span className="flex items-center gap-2 text-xs text-vscode-descriptionForeground shrink-0">
-										<span className="tabular-nums opacity-70">
-											{formatLargeNumber(displayTokens)}
-										</span>
-										<span className="tabular-nums min-w-[45px] text-right">
-											${displayCost.toFixed(2)}
-										</span>
+										{shouldShowCost && (
+											<>
+												<span className="tabular-nums opacity-70">
+													{formatLargeNumber(displayTokens)}
+												</span>
+												<span className="tabular-nums min-w-[45px] text-right">
+													${displayCost.toFixed(2)}
+												</span>
+											</>
+										)}
+										{shouldShowLineChanges && (
+											<span className="tabular-nums ml-2 min-w-[60px] grid grid-cols-2 items-center justify-end">
+												<span
+													className={cn(
+														" text-right",
+														hasAdded ? "font-medium text-vscode-charts-green" : "",
+													)}>
+													{hasAdded ? `+${displayAdded}` : "\u00A0"}
+												</span>
+												<span
+													className={cn(
+														" text-right",
+														hasRemoved ? "font-medium text-vscode-charts-red" : "",
+													)}>
+													{hasRemoved ? `−${displayRemoved}` : "\u00A0"}
+												</span>
+											</span>
+										)}
 									</span>
 								)}
 							</li>

webview-ui/src/components/chat/__tests__/TodoListDisplay.spec.tsx

@@ -34,6 +34,8 @@ describe("TodoListDisplay", () => {
 			name: "Task 1: Change background colour",
 			tokens: 95400,
 			cost: 0.22,
+			added: 10,
+			removed: 4,
 			status: "completed",
 			hasNestedChildren: false,
 		},
@@ -42,6 +44,8 @@ describe("TodoListDisplay", () => {
 			name: "Task 2: Add timestamp to bottom",
 			tokens: 95000,
 			cost: 0.24,
+			added: 3,
+			removed: 2,
 			status: "completed",
 			hasNestedChildren: false,
 		},
@@ -106,7 +110,9 @@ describe("TodoListDisplay", () => {
 
 			// The pending task has no subtaskId, should not show cost
 			const listItems = screen.getAllByRole("listitem")
-			const pendingItem = listItems.find((item) => item.textContent?.includes("Task 3: Pending task"))
+			const pendingItem = listItems.find((item: HTMLElement) =>
+				item.textContent?.includes("Task 3: Pending task"),
+			)
 			expect(pendingItem).toBeDefined()
 			expect(pendingItem?.textContent).not.toContain("$")
 		})
@@ -177,6 +183,96 @@ describe("TodoListDisplay", () => {
 		})
 	})
 
+	describe("line change display", () => {
+		it("uses todo.added/todo.removed when present", () => {
+			const todosWithDirectLineChanges = [
+				{
+					id: "1",
+					content: "Task 1: Change background colour",
+					status: "completed",
+					subtaskId: "subtask-1",
+					added: 7,
+					removed: 9,
+				},
+			]
+			render(<TodoListDisplay todos={todosWithDirectLineChanges} subtaskDetails={subtaskDetails} />)
+
+			// Expand
+			const header = screen.getByText("1 to-dos done")
+			fireEvent.click(header)
+
+			// Line changes are rendered as separate colored spans
+			expect(screen.getByText("+7")).toBeInTheDocument()
+			expect(screen.getByText("−9")).toBeInTheDocument()
+		})
+
+		it("falls back to subtaskDetails when todo added/removed are missing", () => {
+			const todosMissingDirectLineChanges = [
+				{
+					id: "1",
+					content: "Task 1: Change background colour",
+					status: "completed",
+					subtaskId: "subtask-1",
+				},
+			]
+			render(<TodoListDisplay todos={todosMissingDirectLineChanges} subtaskDetails={subtaskDetails} />)
+
+			// Expand
+			const header = screen.getByText("1 to-dos done")
+			fireEvent.click(header)
+
+			// Line changes are rendered as separate colored spans
+			expect(screen.getByText("+10")).toBeInTheDocument()
+			expect(screen.getByText("−4")).toBeInTheDocument()
+		})
+
+		it("hides line deltas when no data available (no subtaskId)", () => {
+			const todosNoSubtaskLink = [{ id: "1", content: "No link todo", status: "completed" }]
+			render(<TodoListDisplay todos={todosNoSubtaskLink} subtaskDetails={subtaskDetails} />)
+
+			// Expand
+			const header = screen.getByText("1 to-dos done")
+			fireEvent.click(header)
+
+			expect(screen.queryByText(/\+\d+/)).not.toBeInTheDocument()
+			expect(screen.queryByText(/−\d+/)).not.toBeInTheDocument()
+		})
+
+		it("hides line deltas when all values are undefined (subtaskId present)", () => {
+			const todosWithLinkButNoLineChanges = [
+				{
+					id: "1",
+					content: "Task 1: Change background colour",
+					status: "completed",
+					subtaskId: "subtask-1",
+				},
+			]
+			const subtaskDetailsWithoutLineChanges: SubtaskDetail[] = [
+				{
+					id: "subtask-1",
+					name: "Task 1: Change background colour",
+					tokens: 95400,
+					cost: 0.22,
+					status: "completed",
+					hasNestedChildren: false,
+				} as unknown as SubtaskDetail,
+			]
+			render(
+				<TodoListDisplay
+					todos={todosWithLinkButNoLineChanges}
+					subtaskDetails={subtaskDetailsWithoutLineChanges}
+				/>,
+			)
+
+			// Expand
+			const header = screen.getByText("1 to-dos done")
+			fireEvent.click(header)
+
+			expect(screen.queryByText(/\+\d+/)).not.toBeInTheDocument()
+			expect(screen.queryByText(/−\d+/)).not.toBeInTheDocument()
+		})
+	})
+
 	describe("click handler", () => {
 		it("should call onSubtaskClick when a todo with subtaskId is clicked", () => {
 			const onSubtaskClick = vi.fn()

webview-ui/src/i18n/locales/ca/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Esperant la tasca filla {{childId}}"
 	},
 	"costs": {
-		"own": "Propi",
+		"own": "Principal",
 		"subtasks": "Subtasques"
+	},
+	"stats": {
+		"lines": "Línies"
 	}
 }

webview-ui/src/i18n/locales/de/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Warte auf Unteraufgabe {{childId}}"
 	},
 	"costs": {
-		"own": "Eigen",
+		"own": "Haupt",
 		"subtasks": "Unteraufgaben"
+	},
+	"stats": {
+		"lines": "Zeilen"
 	}
 }

webview-ui/src/i18n/locales/en/chat.json

@@ -6,6 +6,7 @@
 		"collapse": "Collapse task",
 		"seeMore": "See more",
 		"seeLess": "See less",
+		"lineChanges": "Lines:",
 		"tokens": "Tokens",
 		"cache": "Cache",
 		"apiCost": "API Cost",

webview-ui/src/i18n/locales/en/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Awaiting child task {{childId}}"
 	},
 	"costs": {
-		"own": "Own",
+		"own": "Main",
 		"subtasks": "Subtasks"
+	},
+	"stats": {
+		"lines": "Lines"
 	}
 }

webview-ui/src/i18n/locales/es/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Esperando tarea secundaria {{childId}}"
 	},
 	"costs": {
-		"own": "Propio",
+		"own": "Principal",
 		"subtasks": "Subtareas"
+	},
+	"stats": {
+		"lines": "Líneas"
 	}
 }

webview-ui/src/i18n/locales/fr/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "En attente de la tâche enfant {{childId}}"
 	},
 	"costs": {
-		"own": "Propre",
+		"own": "Principal",
 		"subtasks": "Sous-tâches"
+	},
+	"stats": {
+		"lines": "Lignes"
 	}
 }

webview-ui/src/i18n/locales/hi/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "चाइल्ड कार्य {{childId}} की प्रतीक्षा में"
 	},
 	"costs": {
-		"own": "स्वयं",
+		"own": "मुख्य",
 		"subtasks": "उपकार्य"
+	},
+	"stats": {
+		"lines": "पंक्तियाँ"
 	}
 }

webview-ui/src/i18n/locales/id/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Menunggu tugas anak {{childId}}"
 	},
 	"costs": {
-		"own": "Sendiri",
+		"own": "Utama",
 		"subtasks": "Subtugas"
+	},
+	"stats": {
+		"lines": "Baris"
 	}
 }

webview-ui/src/i18n/locales/it/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "In attesa dell'attività figlia {{childId}}"
 	},
 	"costs": {
-		"own": "Proprio",
+		"own": "Principale",
 		"subtasks": "Sottoattività"
+	},
+	"stats": {
+		"lines": "Linee"
 	}
 }

webview-ui/src/i18n/locales/ja/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "子タスク{{childId}}を待機中"
 	},
 	"costs": {
-		"own": "自身",
+		"own": "メイン",
 		"subtasks": "サブタスク"
+	},
+	"stats": {
+		"lines": "行"
 	}
 }

webview-ui/src/i18n/locales/ko/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "하위 작업 {{childId}} 대기 중"
 	},
 	"costs": {
-		"own": "자체",
+		"own": "메인",
 		"subtasks": "하위작업"
+	},
+	"stats": {
+		"lines": "라인"
 	}
 }

webview-ui/src/i18n/locales/nl/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Wachten op kindtaak {{childId}}"
 	},
 	"costs": {
-		"own": "Eigen",
+		"own": "Hoofd",
 		"subtasks": "Subtaken"
+	},
+	"stats": {
+		"lines": "Regels"
 	}
 }

webview-ui/src/i18n/locales/pl/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Oczekiwanie na zadanie podrzędne {{childId}}"
 	},
 	"costs": {
-		"own": "Własne",
+		"own": "Główne",
 		"subtasks": "Podzadania"
+	},
+	"stats": {
+		"lines": "Linie"
 	}
 }

webview-ui/src/i18n/locales/pt-BR/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Aguardando tarefa filha {{childId}}"
 	},
 	"costs": {
-		"own": "Próprio",
+		"own": "Principal",
 		"subtasks": "Subtarefas"
+	},
+	"stats": {
+		"lines": "Linhas"
 	}
 }

webview-ui/src/i18n/locales/ru/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Ожидание дочерней задачи {{childId}}"
 	},
 	"costs": {
-		"own": "Собственные",
+		"own": "Основная",
 		"subtasks": "Подзадачи"
+	},
+	"stats": {
+		"lines": "Строки"
 	}
 }

webview-ui/src/i18n/locales/tr/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "{{childId}} alt görevi bekleniyor"
 	},
 	"costs": {
-		"own": "Kendi",
+		"own": "Ana",
 		"subtasks": "Alt görevler"
+	},
+	"stats": {
+		"lines": "Satırlar"
 	}
 }

webview-ui/src/i18n/locales/vi/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "Đang chờ nhiệm vụ con {{childId}}"
 	},
 	"costs": {
-		"own": "Riêng",
+		"own": "Chính",
 		"subtasks": "Nhiệm vụ con"
+	},
+	"stats": {
+		"lines": "Dòng"
 	}
 }

webview-ui/src/i18n/locales/zh-CN/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "等待子任务 {{childId}}"
 	},
 	"costs": {
-		"own": "自身",
+		"own": "主要",
 		"subtasks": "子任务"
+	},
+	"stats": {
+		"lines": "行"
 	}
 }

webview-ui/src/i18n/locales/zh-TW/common.json

@@ -108,7 +108,10 @@
 		"awaiting_child": "等待子工作 {{childId}}"
 	},
 	"costs": {
-		"own": "自身",
+		"own": "主要",
 		"subtasks": "子工作"
+	},
+	"stats": {
+		"lines": "行"
 	}
 }

webview-ui/src/types/subtasks.ts

@@ -5,6 +5,10 @@ export type SubtaskDetail = {
 	name: string
 	/** tokensIn + tokensOut */
 	tokens: number
+	/** Total lines added across the subtask */
+	added: number
+	/** Total lines removed across the subtask */
+	removed: number
 	/** Aggregated total cost */
 	cost: number
 	status: "active" | "completed" | "delegated"