diff --git a/src/pages/exam/setup/examCanvasShapes.tsx b/src/pages/exam/setup/examCanvasShapes.tsx
index a58b748..7c36bb3 100644
--- a/src/pages/exam/setup/examCanvasShapes.tsx
+++ b/src/pages/exam/setup/examCanvasShapes.tsx
@@ -1,6 +1,8 @@
 
 import React from 'react'
-import { BaseBoxShapeTool, BaseBoxShapeUtil, HTMLContainer, T, TLBaseBoxShape, toDomPrecision } from '@tldraw/tldraw'
+import { BaseBoxShapeTool, BaseBoxShapeUtil, Edge2d, HTMLContainer, ShapeUtil, T, TLBaseBoxShape, Vec, toDomPrecision } from '@tldraw/tldraw'
+import type { TLHandle } from '@tldraw/tldraw'
+import { PAGE_WIDTH } from '../../../utils/exam-canvas/model'
 import type { ExamCanvasRegionKind, ExamCanvasShapeKind } from '../../../utils/exam-canvas/model'
 
 export const PDF_PAGE_SHAPE_TYPE = 'exam-pdf-page'
@@ -65,10 +67,28 @@ const shapeCss = `
 [data-color-mode="dark"] .exam-canvas-shape__pill, .tl-theme__dark .exam-canvas-shape__pill { background: rgba(15,23,42,.88); color: var(--exam-stroke); box-shadow: 0 1px 5px rgba(0,0,0,.35); }
 `
 
+function renderBoundaryLine(shape: ExamCanvasTLShape) {
+  const p = canvasShapePalette.boundary
+  const lineY = Math.max(1, Math.min(shape.props.h - 1, shape.props.h / 2))
+  return (
+    <HTMLContainer id={shape.id} style={{ width: toDomPrecision(shape.props.w), height: toDomPrecision(shape.props.h), overflow: 'visible', pointerEvents: 'all' }}>
+      <style>{shapeCss}</style>
+      <svg width={toDomPrecision(shape.props.w)} height={toDomPrecision(shape.props.h)} aria-label={`${p.label}: ${p.role}`} style={{ display: 'block', overflow: 'visible' }}>
+        <line x1={0} x2={toDomPrecision(shape.props.w)} y1={lineY} y2={lineY} stroke="var(--exam-stroke)" strokeWidth={2.5} strokeDasharray={p.dash} strokeLinecap="round" style={{ '--exam-light-stroke': p.stroke, '--exam-dark-stroke': p.darkStroke } as React.CSSProperties} />
+      </svg>
+      <span className="exam-canvas-shape__pill" style={{ position: 'absolute', left: 8, top: -24, fontSize: 11, fontWeight: 900, textTransform: 'uppercase', letterSpacing: 0.6, borderRadius: 999, padding: '2px 7px', display: 'inline-flex', alignItems: 'center', gap: 5, color: p.stroke }}>
+        <span aria-hidden="true">{p.icon}</span>
+        {shape.props.label || p.label}
+      </span>
+    </HTMLContainer>
+  )
+}
+
 function renderShape(shape: ExamCanvasTLShape) {
   const kind = shape.props.kind
   const p = canvasShapePalette[kind] ?? canvasShapePalette.response
   const isBoundary = kind === 'boundary'
+  if (isBoundary) return renderBoundaryLine(shape)
   return (
     <HTMLContainer id={shape.id} style={{ width: toDomPrecision(shape.props.w), height: toDomPrecision(shape.props.h), pointerEvents: 'all' }}>
       <style>{shapeCss}</style>
@@ -121,7 +141,55 @@ class PdfPageUtil extends BaseBoxShapeUtil<ExamPdfPageTLShape> {
   }
   override indicator(shape: ExamPdfPageTLShape) { return ind(shape) }
 }
-class BoundaryUtil extends BaseBoxShapeUtil<ExamCanvasTLShape> { static override type = SHAPE_TYPES.boundary; static override props = sharedProps; override getDefaultProps(){ return defaultProps('boundary', 680, 8) }; override component(shape: ExamCanvasTLShape){ return renderShape(shape) }; override indicator(shape: ExamCanvasTLShape){ return ind(shape) } }
+class BoundaryUtil extends ShapeUtil<ExamCanvasTLShape> {
+  static override type = SHAPE_TYPES.boundary
+  static override props = sharedProps
+
+  override getDefaultProps() { return defaultProps('boundary', PAGE_WIDTH, 8) }
+  override canEdit() { return false }
+  override canResize() { return false }
+  override canBind() { return false }
+  override hideResizeHandles() { return true }
+  override hideRotateHandle() { return true }
+  override hideSelectionBoundsBg() { return true }
+
+  private pageSpanForY(y: number) {
+    const pages = this.editor.getCurrentPageShapes().filter((shape): shape is ExamPdfPageTLShape => shape.type === PDF_PAGE_SHAPE_TYPE)
+    const hit = pages.find((page) => y >= page.y && y <= page.y + page.props.h)
+    const nearest = hit ?? pages.reduce<ExamPdfPageTLShape | null>((best, page) => {
+      if (!best) return page
+      const pageDy = Math.min(Math.abs(y - page.y), Math.abs(y - (page.y + page.props.h)))
+      const bestDy = Math.min(Math.abs(y - best.y), Math.abs(y - (best.y + best.props.h)))
+      return pageDy < bestDy ? page : best
+    }, null)
+    return nearest ? { x: nearest.x, w: nearest.props.w } : { x: 0, w: PAGE_WIDTH }
+  }
+
+  private normalize(shape: ExamCanvasTLShape): ExamCanvasTLShape {
+    const span = this.pageSpanForY(shape.y + shape.props.h / 2)
+    return { ...shape, x: span.x, rotation: 0, props: { ...shape.props, w: span.w, h: 8, kind: 'boundary' } }
+  }
+
+  override getGeometry(shape: ExamCanvasTLShape) {
+    const y = shape.props.h / 2
+    return new Edge2d({ start: new Vec(0, y), end: new Vec(shape.props.w, y) })
+  }
+
+  override getHandles(shape: ExamCanvasTLShape): TLHandle[] {
+    return [{ id: 'y', type: 'vertex', index: 'a1' as any, x: shape.props.w / 2, y: shape.props.h / 2, canSnap: false }]
+  }
+
+  override onBeforeCreate(next: ExamCanvasTLShape) { return this.normalize(next) }
+  override onBeforeUpdate(_prev: ExamCanvasTLShape, next: ExamCanvasTLShape) { return this.normalize(next) }
+  override onTranslate(initial: ExamCanvasTLShape, current: ExamCanvasTLShape): any {
+    return this.normalize({ ...current, x: initial.x })
+  }
+  override onHandleDrag(shape: ExamCanvasTLShape, { handle }: { handle: TLHandle }): any {
+    return this.normalize({ ...shape, y: shape.y + handle.y - shape.props.h / 2 })
+  }
+  override component(shape: ExamCanvasTLShape) { return renderShape(shape) }
+  override indicator(shape: ExamCanvasTLShape) { return <path d={`M 0 ${toDomPrecision(shape.props.h / 2)} L ${toDomPrecision(shape.props.w)} ${toDomPrecision(shape.props.h / 2)}`} /> }
+}
 class PartUtil extends BaseBoxShapeUtil<ExamCanvasTLShape> { static override type = SHAPE_TYPES.part; static override props = sharedProps; override getDefaultProps(){ return defaultProps('part', 420, 170) }; override component(shape: ExamCanvasTLShape){ return renderShape(shape) }; override indicator(shape: ExamCanvasTLShape){ return ind(shape) } }
 function regionUtil(type: string, kind: ExamCanvasRegionKind, w = 360, h = 120) { return class extends BaseBoxShapeUtil<ExamCanvasTLShape> { static override type = type; static override props = sharedProps; override getDefaultProps(){ return defaultProps(kind, w, h) }; override component(shape: ExamCanvasTLShape){ return renderShape(shape) }; override indicator(shape: ExamCanvasTLShape){ return ind(shape) } } }
 
diff --git a/src/utils/exam-canvas/model.test.ts b/src/utils/exam-canvas/model.test.ts
index 52b40b7..b8e3add 100644
--- a/src/utils/exam-canvas/model.test.ts
+++ b/src/utils/exam-canvas/model.test.ts
@@ -43,6 +43,7 @@ describe('exam setup canvas serialization', () => {
     ], pages)
     expect(payload.questions.find((q) => !q.is_container)?.page).toBe(2)
     expect(payload.boundaries.every((b) => b.page_index === 1)).toBe(true)
+    expect(payload.boundaries.every((b) => b.bounds?.x === 260 && b.bounds?.w === 780)).toBe(true)
     expect(payload.response_areas[0].page).toBe(2)
   })
 
@@ -60,6 +61,7 @@ describe('exam setup canvas serialization', () => {
       boundaries: [{ id: 'b1', template_id: 'tpl-1', question_id: 'q1', label: 'Q1 start', page_index: 0, y: 100, bounds: { x: 0, y: 100, w: 700, h: 8 }, source: 'manual', confirmed: true }],
     })
     expect(shapes.map((s) => s.kind).sort()).toEqual(['boundary', 'furniture', 'part', 'response'])
+    expect(shapes.find((s) => s.kind === 'boundary')).toMatchObject({ id: 'b1', x: 0, y: 100, w: 780, h: 8 })
     expect(shapes.find((s) => s.kind === 'part')).toMatchObject({ id: 'p1', x: 1, y: 2, w: 3, h: 4 })
   })
 })
diff --git a/src/utils/exam-canvas/model.ts b/src/utils/exam-canvas/model.ts
index 22bdb54..b885161 100644
--- a/src/utils/exam-canvas/model.ts
+++ b/src/utils/exam-canvas/model.ts
@@ -65,10 +65,19 @@ export function newDomainId(): string {
   })
 }
 
-function bounds(shape: Pick<ExamCanvasShapeModel, 'x' | 'y' | 'w' | 'h'>): CanvasBounds {
+function bounds(shape: Pick<ExamCanvasShapeModel, 'x' | 'y' | 'w' | 'h'>): CanvasBounds & Record<string, number> {
   return { x: shape.x, y: shape.y, w: shape.w, h: shape.h }
 }
 
+function pageGeometry(pageNumber: number, pages?: CanvasPageGeometry[]): CanvasPageGeometry {
+  return pages?.find((page) => page.pageNumber === pageNumber) ?? { pageNumber, x: 0, y: pageTop(pageNumber, pages), w: PAGE_WIDTH, h: PAGE_HEIGHT }
+}
+
+function boundaryBounds(shape: Pick<ExamCanvasShapeModel, 'y' | 'h'>, pages?: CanvasPageGeometry[]): CanvasBounds & Record<string, number> {
+  const page = pageGeometry(pageForShape(shape, pages), pages)
+  return { x: page.x, y: shape.y, w: page.w, h: 8 }
+}
+
 function contains(outer: CanvasBounds, inner: CanvasBounds): boolean {
   const ox2 = outer.x + outer.w
   const oy2 = outer.y + outer.h
@@ -105,7 +114,7 @@ export function serializeCanvasShapes(template: ExamTemplateDetail, shapes: Exam
     questions.push({ id: questionId, label, order: qNum - 1, max_marks: 0, is_container: true, mark_scheme: {} })
     bands.push({ questionId, top, bottom })
     for (const b of [top, bottom]) {
-      boundaries.push({ id: isUuid(b.id) ? b.id : newDomainId(), question_id: questionId, label: b === top ? `${label} start` : `${label} end`, page_index: pageForShape(b, pages) - 1, y: b.y, bounds: bounds(b), source: 'manual', confirmed: true })
+      boundaries.push({ id: isUuid(b.id) ? b.id : newDomainId(), question_id: questionId, label: b === top ? `${label} start` : `${label} end`, page_index: pageForShape(b, pages) - 1, y: b.y, bounds: boundaryBounds(b, pages), source: 'manual', confirmed: true })
     }
   }
 
@@ -134,8 +143,10 @@ export function shapesFromTemplate(detail: ExamTemplateDetail, pages?: CanvasPag
   const shapes: ExamCanvasShapeModel[] = []
   const questions = new Map(detail.questions.map((q) => [q.id, q]))
   for (const b of detail.boundaries ?? []) {
-    const bb = b.bounds ?? { x: 48, y: b.y, w: PAGE_WIDTH - 96, h: 8 }
-    shapes.push({ id: b.id, kind: 'boundary', x: Number(bb.x ?? 48), y: Number(bb.y ?? b.y), w: Number(bb.w ?? PAGE_WIDTH - 96), h: Number(bb.h ?? 8), label: b.label ?? undefined, questionId: b.question_id })
+    const page = pageGeometry((b.page_index ?? 0) + 1, pages)
+    // Boundary rows are y-lines. The old bounds rect is vestigial: keep y/domain ids,
+    // but render and save a full rendered-page-width horizontal rule.
+    shapes.push({ id: b.id, kind: 'boundary', x: page.x, y: Number(b.y), w: page.w, h: 8, label: b.label ?? undefined, questionId: b.question_id })
   }
   for (const q of detail.questions ?? []) {
     if (q.is_container || !q.bounds) continue