diff --git a/src/historicalStore.test.ts b/src/historicalStore.test.ts
index 7158462..185db9a 100644
--- a/src/historicalStore.test.ts
+++ b/src/historicalStore.test.ts
@@ -94,11 +94,13 @@ describe('HistoricalStore', () => {
     });
 
     it('should record task completion', () => {
+      const startedAt = Date.now() - 60000;
+      const endedAt = startedAt + 60000;
       const taskId = store.recordTask({
         workerId: 'worker-1',
         taskType: 'bead',
-        startedAt: Date.now() - 60000,
-        endedAt: Date.now(),
+        startedAt,
+        endedAt,
         cost: 0.05,
         tokensIn: 500,
         tokensOut: 200,
@@ -511,14 +513,14 @@ describe('HistoricalStore', () => {
       const summaries = store.getSessionWorkerSummaries({ sessionId: 'otlp-metric-sess' });
       expect(summaries).toHaveLength(1);
       const summary = summaries[0];
-      expect(summary.worker_id).toBe('needle-alpha');
-      expect(summary.tokens_in).toBe(1500);
-      expect(summary.tokens_out).toBe(600);
-      expect(summary.cost_usd).toBeCloseTo(0.084);
-      expect(summary.beads_completed).toBe(2);
-      expect(summary.beads_failed).toBe(1);
+      expect(summary.workerId).toBe('needle-alpha');
+      expect(summary.tokensIn).toBe(1500);
+      expect(summary.tokensOut).toBe(600);
+      expect(summary.costUsd).toBeCloseTo(0.084);
+      expect(summary.beadsCompleted).toBe(2);
+      expect(summary.beadsFailed).toBe(1);
       expect(summary.errors).toBe(1);
-      expect(summary.metrics_source).toBe('otlp-metric');
+      expect(summary.metricsSource).toBe('otlp-metric');
 
       // Verify getAggregatedAnalytics prefers metric-sourced data
       store.endSession({
@@ -695,9 +697,9 @@ describe('HistoricalStore', () => {
 
       const summaries = store.getSessionWorkerSummaries({ sessionId: 'no-cost-sess' });
       expect(summaries).toHaveLength(1);
-      expect(summaries[0].metrics_source).toBe('otlp-metric');
-      expect(summaries[0].tokens_in).toBe(800);
-      expect(summaries[0].cost_usd).toBe(0);
+      expect(summaries[0].metricsSource).toBe('otlp-metric');
+      expect(summaries[0].tokensIn).toBe(800);
+      expect(summaries[0].costUsd).toBe(0);
 
       store.endSession({ workerCount: 1, taskCount: 0, totalCost: 0, totalTokens: 800, metricsSource: 'otlp-metric' });
     });
diff --git a/src/historicalStore.ts b/src/historicalStore.ts
index f3ea345..1cea2a4 100644
--- a/src/historicalStore.ts
+++ b/src/historicalStore.ts
@@ -586,7 +586,7 @@ export class HistoricalStore {
 
     query += ' ORDER BY updated_at DESC';
 
-    return this.db.prepare(query).all(...params) as Array<{
+    const rows = this.db.prepare(query).all(...params) as Array<{
       id: number;
       session_id: string;
       worker_id: string;
@@ -599,6 +599,18 @@ export class HistoricalStore {
       metrics_source: string;
       updated_at: number;
     }>;
+
+    return rows.map(row => ({
+      sessionId: row.session_id,
+      workerId: row.worker_id,
+      tokensIn: row.tokens_in,
+      tokensOut: row.tokens_out,
+      costUsd: row.cost_usd,
+      beadsCompleted: row.beads_completed,
+      beadsFailed: row.beads_failed,
+      errors: row.errors,
+      metricsSource: row.metrics_source,
+    }));
   }
 
   /**
@@ -1001,7 +1013,7 @@ export class HistoricalStore {
     const { startTime = 0, endTime = Date.now() } = options;
 
     // Get sessions in range
-    const sessions = this.getSingsInRange(startTime, endTime);
+    const sessions = this.getSessionsInRange(startTime, endTime);
     const sessionIds = sessions.map(s => s.id);
 
     // Fetch metric-sourced worker summaries for these sessions
@@ -1210,7 +1222,7 @@ export class HistoricalStore {
   /**
    * Helper to get sessions in a time range
    */
-  private getSingsInRange(startTime: number, endTime: number): SessionRecord[] {
+  private getSessionsInRange(startTime: number, endTime: number): SessionRecord[] {
     return this.db.prepare(`
       SELECT * FROM sessions
       WHERE started_at >= ? AND ended_at <= ?