diff --git a/openspec/changes/multi-chart-management/tasks.md b/openspec/changes/multi-chart-management/tasks.md
index be610ff..007d567 100644
--- a/openspec/changes/multi-chart-management/tasks.md
+++ b/openspec/changes/multi-chart-management/tasks.md
@@ -21,10 +21,10 @@
 
 ## 4. Candles & Annotations API Scoping
 
-- [ ] 4.1 Modify `GET /api/candles` to accept `?chartId=` query param and filter by chart_id (fall back to most recent chart if omitted)
-- [ ] 4.2 Modify `GET /api/annotations` to accept `?chartId=` query param and filter by chart_id (fall back to most recent chart if omitted)
-- [ ] 4.3 Modify `POST /api/annotations` to require `chart_id` in request body and store it
-- [ ] 4.4 Modify `GET /api/export` to accept `?chartId=` query param and scope exported annotations to that chart
+- [x] 4.1 Modify `GET /api/candles` to accept `?chartId=` query param and filter by chart_id (fall back to most recent chart if omitted)
+- [x] 4.2 Modify `GET /api/annotations` to accept `?chartId=` query param and filter by chart_id (fall back to most recent chart if omitted)
+- [x] 4.3 Modify `POST /api/annotations` to require `chart_id` in request body and store it
+- [x] 4.4 Modify `GET /api/export` to accept `?chartId=` query param and scope exported annotations to that chart
 
 ## 5. Chart Selector UI Component
 
diff --git a/src/app/api/annotations/route.ts b/src/app/api/annotations/route.ts
index 6dcfeff..cf57b8c 100644
--- a/src/app/api/annotations/route.ts
+++ b/src/app/api/annotations/route.ts
@@ -1,12 +1,27 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { db } from '@/lib/db';
-import { annotations } from '@/lib/db/schema';
-import { eq, inArray } from 'drizzle-orm';
+import { annotations, charts } from '@/lib/db/schema';
+import { eq, inArray, and, desc } from 'drizzle-orm';
 
-// GET all annotations
-export async function GET() {
+// GET annotations scoped by chartId
+export async function GET(request: NextRequest) {
   try {
-    const allAnnotations = await db.select().from(annotations);
+    const { searchParams } = request.nextUrl;
+    let chartId = searchParams.get('chartId');
+
+    // Fall back to most recent chart if no chartId provided
+    if (!chartId) {
+      const latest = await db.select({ id: charts.id }).from(charts).orderBy(desc(charts.created_at)).limit(1);
+      if (latest.length === 0) {
+        return NextResponse.json([]);
+      }
+      chartId = String(latest[0].id);
+    }
+
+    const allAnnotations = await db
+      .select()
+      .from(annotations)
+      .where(eq(annotations.chart_id, parseInt(chartId, 10)));
 
     // Parse geometry from JSON string
     const parsed = allAnnotations.map((annotation) => ({
@@ -23,26 +38,36 @@ export async function GET() {
   }
 }
 
-// POST create new annotation
+// POST create new annotation (requires chart_id)
 export async function POST(request: NextRequest) {
   try {
     const body = await request.json();
-    const { timestamp, label_type, geometry, color } = body;
+    const { timestamp, label_type, chart_id, geometry, color } = body;
 
     // Validate required fields
-    if (!timestamp || !label_type) {
+    if (!timestamp || !label_type || !chart_id) {
       return NextResponse.json(
-        { error: 'timestamp and label_type are required' },
+        { error: 'timestamp, label_type, and chart_id are required' },
         { status: 400 }
       );
     }
 
+    // Verify chart exists
+    const chartExists = await db.select({ id: charts.id }).from(charts).where(eq(charts.id, chart_id)).limit(1);
+    if (chartExists.length === 0) {
+      return NextResponse.json(
+        { error: 'Chart not found' },
+        { status: 404 }
+      );
+    }
+
     // Serialize geometry to JSON string if present
     const geometryString = geometry ? JSON.stringify(geometry) : null;
 
     const result = await db
       .insert(annotations)
       .values({
+        chart_id,
         timestamp,
         label_type,
         geometry: geometryString,
@@ -68,27 +93,36 @@ export async function POST(request: NextRequest) {
   }
 }
 
-// DELETE annotations with bulk operations
+// DELETE annotations with bulk operations (scoped by chartId)
 export async function DELETE(request: NextRequest) {
   try {
     const { searchParams } = request.nextUrl;
     const type = searchParams.get('type');
     const all = searchParams.get('all');
+    const chartId = searchParams.get('chartId');
 
     let result;
 
     if (all === 'true') {
-      // Delete all annotations
-      result = await db.delete(annotations).returning();
+      if (chartId) {
+        result = await db.delete(annotations).where(eq(annotations.chart_id, parseInt(chartId, 10))).returning();
+      } else {
+        result = await db.delete(annotations).returning();
+      }
     } else if (type) {
-      // Delete by type(s)
       const types = type.split(',').map((t) => t.trim());
-      result = await db
-        .delete(annotations)
-        .where(inArray(annotations.label_type, types))
-        .returning();
+      if (chartId) {
+        result = await db
+          .delete(annotations)
+          .where(and(inArray(annotations.label_type, types), eq(annotations.chart_id, parseInt(chartId, 10))))
+          .returning();
+      } else {
+        result = await db
+          .delete(annotations)
+          .where(inArray(annotations.label_type, types))
+          .returning();
+      }
     } else {
-      // No filter specified
       return NextResponse.json(
         { error: 'Specify type or all parameter for bulk delete' },
         { status: 400 }
diff --git a/src/app/api/candles/route.ts b/src/app/api/candles/route.ts
index cd90f6b..cce9088 100644
--- a/src/app/api/candles/route.ts
+++ b/src/app/api/candles/route.ts
@@ -1,13 +1,32 @@
-import { NextResponse } from 'next/server';
+import { NextRequest, NextResponse } from 'next/server';
 import { db } from '@/lib/db';
-import { candles } from '@/lib/db/schema';
-import { asc } from 'drizzle-orm';
+import { candles, charts } from '@/lib/db/schema';
+import { asc, desc, eq } from 'drizzle-orm';
 
-export async function GET() {
+export async function GET(request: NextRequest) {
   try {
+    const { searchParams } = request.nextUrl;
+    let chartId = searchParams.get('chartId');
+
+    // Fall back to most recent chart if no chartId provided
+    if (!chartId) {
+      const latest = await db.select({ id: charts.id }).from(charts).orderBy(desc(charts.created_at)).limit(1);
+      if (latest.length === 0) {
+        return NextResponse.json([]);
+      }
+      chartId = String(latest[0].id);
+    }
+
     const allCandles = await db
-      .select()
+      .select({
+        time: candles.time,
+        open: candles.open,
+        high: candles.high,
+        low: candles.low,
+        close: candles.close,
+      })
       .from(candles)
+      .where(eq(candles.chart_id, parseInt(chartId, 10)))
       .orderBy(asc(candles.time));
 
     return NextResponse.json(allCandles);
diff --git a/src/app/api/export/route.ts b/src/app/api/export/route.ts
index 075b504..17d202f 100644
--- a/src/app/api/export/route.ts
+++ b/src/app/api/export/route.ts
@@ -1,11 +1,32 @@
-import { NextResponse } from 'next/server';
+import { NextRequest, NextResponse } from 'next/server';
 import { db } from '@/lib/db';
-import { annotations, candles } from '@/lib/db/schema';
-import { eq } from 'drizzle-orm';
+import { annotations, candles, charts } from '@/lib/db/schema';
+import { eq, and, desc } from 'drizzle-orm';
 
-export async function GET() {
+export async function GET(request: NextRequest) {
   try {
-    const allAnnotations = await db.select().from(annotations);
+    const { searchParams } = request.nextUrl;
+    let chartId = searchParams.get('chartId');
+
+    // Fall back to most recent chart if no chartId provided
+    if (!chartId) {
+      const latest = await db.select({ id: charts.id }).from(charts).orderBy(desc(charts.created_at)).limit(1);
+      if (latest.length === 0) {
+        return new NextResponse('timestamp,label_type,price\n', {
+          headers: {
+            'Content-Type': 'text/csv',
+            'Content-Disposition': 'attachment; filename="annotations.csv"',
+          },
+        });
+      }
+      chartId = String(latest[0].id);
+    }
+
+    const chartIdNum = parseInt(chartId, 10);
+    const allAnnotations = await db
+      .select()
+      .from(annotations)
+      .where(eq(annotations.chart_id, chartIdNum));
 
     // Build CSV content
     const csvRows = ['timestamp,label_type,price'];
@@ -14,18 +35,16 @@ export async function GET() {
       let price: number | null = null;
 
       if (annotation.label_type === 'break_up' || annotation.label_type === 'break_down') {
-        // For marker annotations, look up the candle's close price
         const candleResult = await db
           .select()
           .from(candles)
-          .where(eq(candles.time, annotation.timestamp))
+          .where(and(eq(candles.chart_id, chartIdNum), eq(candles.time, annotation.timestamp)))
           .limit(1);
 
         if (candleResult.length > 0) {
           price = candleResult[0].close;
         }
       } else if (annotation.label_type === 'line' && annotation.geometry) {
-        // For line annotations, use startPrice from geometry
         const geometry = JSON.parse(annotation.geometry);
         price = geometry.startPrice || null;
       }