fix(cli-proxy): durable analytics history persistence and dedupe migration

src/web-server/usage/cliproxy-usage-syncer.ts

@@ -12,30 +12,43 @@ import * as fs from 'fs';
 import * as path from 'path';
 import { fetchCliproxyUsageRaw } from '../../cliproxy/stats-fetcher';
 import {
-  transformCliproxyToDailyUsage,
-  transformCliproxyToHourlyUsage,
-  transformCliproxyToMonthlyUsage,
+  buildCliproxyUsageHistoryAggregates,
+  extractCliproxyUsageHistoryDetails,
+  mergeCliproxyUsageHistoryDetails,
+  pruneCliproxyUsageHistoryDetails,
+  type CliproxyUsageHistoryDetail,
 } from './cliproxy-usage-transformer';
 import type { DailyUsage, HourlyUsage, MonthlyUsage } from './types';
 import { getCcsDir } from '../../utils/config-manager';
 import { ok, info, warn } from '../../utils/ui';
 
-// ---------------------------------------------------------------------------
-// Snapshot format
-// ---------------------------------------------------------------------------
-
 interface CliproxyUsageSnapshot {
   version: number;
   timestamp: number;
+  details: CliproxyUsageHistoryDetail[];
   daily: DailyUsage[];
   hourly: HourlyUsage[];
   monthly: MonthlyUsage[];
 }
 
+type LegacyCliproxyUsageSnapshot = {
+  version?: number;
+  timestamp?: number;
+  daily?: DailyUsage[];
+  hourly?: HourlyUsage[];
+  monthly?: MonthlyUsage[];
+};
+
 type FetchCliproxyUsageRaw = typeof fetchCliproxyUsageRaw;
 
-const SNAPSHOT_VERSION = 2;
+const SNAPSHOT_VERSION = 3;
 const SNAPSHOT_MAX_AGE_MS = 7 * 24 * 60 * 60 * 1000;
+const HISTORY_RETENTION_DAYS = Math.max(
+  30,
+  parseInt(process.env.CCS_CLIPROXY_HISTORY_RETENTION_DAYS ?? '365', 10) || 365
+);
+const HISTORY_RETENTION_MS = HISTORY_RETENTION_DAYS * 24 * 60 * 60 * 1000;
+const MAX_WRITE_ATTEMPTS = 3;
 
 /** Sync interval in ms, configurable via CCS_CLIPROXY_SYNC_INTERVAL env var (default: 5 min) */
 const SYNC_INTERVAL_MS = Math.max(
@@ -43,14 +56,9 @@ const SYNC_INTERVAL_MS = Math.max(
   parseInt(process.env.CCS_CLIPROXY_SYNC_INTERVAL ?? '300000', 10) || 300_000
 );
 
-// Module-level interval ID
 let syncIntervalId: ReturnType<typeof setInterval> | null = null;
 let snapshotTimestampOrdinal = 0;
 
-// ---------------------------------------------------------------------------
-// Cache directory helpers
-// ---------------------------------------------------------------------------
-
 function getCliproxyCacheDir(): string {
   return path.join(getCcsDir(), 'cache', 'cliproxy-usage');
 }
@@ -71,6 +79,88 @@ function getSnapshotTimestamp(): number {
   return Date.now() + snapshotTimestampOrdinal / 1000;
 }
 
+function buildHourlyTimestamp(hour: string): string {
+  return `${hour.replace(' ', 'T')}:00.000Z`;
+}
+
+function buildDailyTimestamp(date: string): string {
+  return `${date}T00:00:00.000Z`;
+}
+
+function buildLegacyHistoryDetails(
+  snapshot: LegacyCliproxyUsageSnapshot
+): CliproxyUsageHistoryDetail[] {
+  const details: CliproxyUsageHistoryDetail[] = [];
+  const coveredDailyKeys = new Set<string>();
+
+  for (const hour of snapshot.hourly ?? []) {
+    for (const breakdown of hour.modelBreakdowns) {
+      details.push({
+        model: breakdown.modelName,
+        timestamp: buildHourlyTimestamp(hour.hour),
+        source: hour.source,
+        authIndex: 'legacy-hourly',
+        inputTokens: breakdown.inputTokens,
+        outputTokens: breakdown.outputTokens,
+        cacheReadTokens: breakdown.cacheReadTokens,
+        failed: false,
+      });
+      coveredDailyKeys.add(`${hour.hour.slice(0, 10)}|${breakdown.modelName}`);
+    }
+  }
+
+  for (const day of snapshot.daily ?? []) {
+    for (const breakdown of day.modelBreakdowns) {
+      const key = `${day.date}|${breakdown.modelName}`;
+      if (coveredDailyKeys.has(key)) {
+        continue;
+      }
+
+      details.push({
+        model: breakdown.modelName,
+        timestamp: buildDailyTimestamp(day.date),
+        source: day.source,
+        authIndex: 'legacy-daily',
+        inputTokens: breakdown.inputTokens,
+        outputTokens: breakdown.outputTokens,
+        cacheReadTokens: breakdown.cacheReadTokens,
+        failed: false,
+      });
+    }
+  }
+
+  return details;
+}
+
+function migrateLegacySnapshot(
+  snapshot: LegacyCliproxyUsageSnapshot,
+  emitWarnings: boolean
+): CliproxyUsageSnapshot | null {
+  const details = buildLegacyHistoryDetails(snapshot);
+  if (details.length === 0) {
+    if (emitWarnings) {
+      console.log(
+        info('CLIProxy legacy snapshot had no migratable history, will refresh on next sync')
+      );
+    }
+    return null;
+  }
+
+  if (emitWarnings) {
+    console.log(info('Loaded legacy CLIProxy snapshot into historical format'));
+  }
+
+  const { daily, hourly, monthly } = buildCliproxyUsageHistoryAggregates(details);
+  return {
+    version: SNAPSHOT_VERSION,
+    timestamp: Number.isFinite(snapshot.timestamp) ? Number(snapshot.timestamp) : Date.now(),
+    details,
+    daily,
+    hourly,
+    monthly,
+  };
+}
+
 function readSnapshot(emitWarnings = true): CliproxyUsageSnapshot | null {
   try {
     const snapshotPath = getLatestSnapshotPath();
@@ -79,23 +169,34 @@ function readSnapshot(emitWarnings = true): CliproxyUsageSnapshot | null {
     }
 
     const raw = fs.readFileSync(snapshotPath, 'utf-8');
-    const snapshot = JSON.parse(raw) as CliproxyUsageSnapshot;
+    const snapshot = JSON.parse(raw) as CliproxyUsageSnapshot | LegacyCliproxyUsageSnapshot;
 
-    if (snapshot.version !== SNAPSHOT_VERSION) {
-      if (emitWarnings) {
-        console.log(info('CLIProxy snapshot version mismatch, will refresh on next sync'));
+    if (snapshot.version === SNAPSHOT_VERSION) {
+      if (!Number.isFinite(snapshot.timestamp)) {
+        if (emitWarnings) {
+          console.log(info('CLIProxy snapshot timestamp invalid, will refresh on next sync'));
+        }
+        return null;
       }
-      return null;
+
+      if (!Array.isArray((snapshot as CliproxyUsageSnapshot).details)) {
+        if (emitWarnings) {
+          console.log(info('CLIProxy snapshot details missing, will refresh on next sync'));
+        }
+        return null;
+      }
+
+      return snapshot as CliproxyUsageSnapshot;
     }
 
-    if (!Number.isFinite(snapshot.timestamp)) {
-      if (emitWarnings) {
-        console.log(info('CLIProxy snapshot timestamp invalid, will refresh on next sync'));
-      }
-      return null;
+    if (snapshot.version === 2) {
+      return migrateLegacySnapshot(snapshot as LegacyCliproxyUsageSnapshot, emitWarnings);
     }
 
-    return snapshot;
+    if (emitWarnings) {
+      console.log(info('CLIProxy snapshot version mismatch, will refresh on next sync'));
+    }
+    return null;
   } catch (err) {
     if (emitWarnings) {
       console.log(warn('Failed to read CLIProxy snapshot:') + ` ${(err as Error).message}`);
@@ -104,14 +205,55 @@ function readSnapshot(emitWarnings = true): CliproxyUsageSnapshot | null {
   }
 }
 
-// ---------------------------------------------------------------------------
-// Load cached data
-// ---------------------------------------------------------------------------
+function buildSnapshot(
+  baseDetails: CliproxyUsageHistoryDetail[],
+  incomingDetails: CliproxyUsageHistoryDetail[]
+): CliproxyUsageSnapshot {
+  const mergedDetails = pruneCliproxyUsageHistoryDetails(
+    mergeCliproxyUsageHistoryDetails(baseDetails, incomingDetails),
+    Date.now() - HISTORY_RETENTION_MS
+  );
+  const { daily, hourly, monthly } = buildCliproxyUsageHistoryAggregates(mergedDetails);
+
+  return {
+    version: SNAPSHOT_VERSION,
+    timestamp: getSnapshotTimestamp(),
+    details: mergedDetails,
+    daily,
+    hourly,
+    monthly,
+  };
+}
+
+async function writeSnapshotWithMerge(
+  incomingDetails: CliproxyUsageHistoryDetail[]
+): Promise<void> {
+  ensureCliproxyCacheDir();
+  const snapshotPath = getLatestSnapshotPath();
+
+  for (let attempt = 0; attempt < MAX_WRITE_ATTEMPTS; attempt++) {
+    const baseSnapshot = readSnapshot(false);
+    const baseTimestamp = baseSnapshot?.timestamp ?? -Infinity;
+    const snapshot = buildSnapshot(baseSnapshot?.details ?? [], incomingDetails);
+    const tempFile = `${snapshotPath}.${process.pid}.${snapshot.timestamp}.tmp`;
+
+    fs.writeFileSync(tempFile, JSON.stringify(snapshot), 'utf-8');
+
+    const latestSnapshot = readSnapshot(false);
+    const latestTimestamp = latestSnapshot?.timestamp ?? -Infinity;
+    if (latestTimestamp > baseTimestamp) {
+      fs.rmSync(tempFile, { force: true });
+      continue;
+    }
+
+    fs.renameSync(tempFile, snapshotPath);
+    console.log(ok('CLIProxy usage snapshot updated'));
+    return;
+  }
+
+  throw new Error('Failed to write CLIProxy snapshot after repeated overlap retries');
+}
 
-/**
- * Read the latest CLIProxy usage snapshot from disk.
- * Returns empty arrays on failure (file not found, parse error, version mismatch).
- */
 export async function loadCachedCliproxyData(): Promise<{
   daily: DailyUsage[];
   hourly: HourlyUsage[];
@@ -132,18 +274,9 @@ export async function loadCachedCliproxyData(): Promise<{
   return { daily: snapshot.daily, hourly: snapshot.hourly, monthly: snapshot.monthly };
 }
 
-// ---------------------------------------------------------------------------
-// Sync
-// ---------------------------------------------------------------------------
-
-/**
- * Fetch latest CLIProxy usage data and persist a snapshot to disk.
- * Non-fatal: logs warning and returns early if CLIProxy is unavailable.
- */
 export async function syncCliproxyUsage(
   fetchRaw: FetchCliproxyUsageRaw = fetchCliproxyUsageRaw
 ): Promise<void> {
-  const syncStartedAt = getSnapshotTimestamp();
   const raw = await fetchRaw();
 
   if (raw === null) {
@@ -152,53 +285,12 @@ export async function syncCliproxyUsage(
   }
 
   try {
-    ensureCliproxyCacheDir();
-
-    const daily = transformCliproxyToDailyUsage(raw);
-    const hourly = transformCliproxyToHourlyUsage(raw);
-    const monthly = transformCliproxyToMonthlyUsage(raw);
-
-    const snapshot: CliproxyUsageSnapshot = {
-      version: SNAPSHOT_VERSION,
-      timestamp: syncStartedAt,
-      daily,
-      hourly,
-      monthly,
-    };
-
-    const snapshotPath = getLatestSnapshotPath();
-    const tempFile = `${snapshotPath}.${process.pid}.${syncStartedAt}.tmp`;
-    const currentSnapshot = readSnapshot(false);
-    if (currentSnapshot && currentSnapshot.timestamp > snapshot.timestamp) {
-      console.log(info('Skipping stale CLIProxy snapshot write'));
-      return;
-    }
-
-    fs.writeFileSync(tempFile, JSON.stringify(snapshot), 'utf-8');
-    const latestSnapshot = readSnapshot(false);
-    if (latestSnapshot && latestSnapshot.timestamp > snapshot.timestamp) {
-      fs.rmSync(tempFile, { force: true });
-      console.log(info('Skipping stale CLIProxy snapshot write'));
-      return;
-    }
-
-    fs.renameSync(tempFile, snapshotPath);
-
-    console.log(ok('CLIProxy usage snapshot updated'));
+    await writeSnapshotWithMerge(extractCliproxyUsageHistoryDetails(raw));
   } catch (err) {
-    // Non-fatal - stale snapshot will continue to be served
     console.log(warn('Failed to write CLIProxy snapshot:') + ` ${(err as Error).message}`);
   }
 }
 
-// ---------------------------------------------------------------------------
-// Interval management
-// ---------------------------------------------------------------------------
-
-/**
- * Start periodic CLIProxy usage sync (every 5 minutes).
- * Performs an immediate sync on startup.
- */
 export function startCliproxySync(syncNow: () => Promise<void> = () => syncCliproxyUsage()): void {
   if (syncIntervalId !== null) {
     return;
@@ -207,7 +299,6 @@ export function startCliproxySync(syncNow: () => Promise<void> = () => syncClipr
   const intervalMin = Math.round(SYNC_INTERVAL_MS / 60_000);
   console.log(info(`Starting CLIProxy usage sync (interval: ${intervalMin} min)`));
 
-  // Fire-and-forget initial sync
   void syncNow();
 
   syncIntervalId = setInterval(() => {
@@ -215,9 +306,6 @@ export function startCliproxySync(syncNow: () => Promise<void> = () => syncClipr
   }, SYNC_INTERVAL_MS);
 }
 
-/**
- * Stop periodic CLIProxy usage sync.
- */
 export function stopCliproxySync(): void {
   if (syncIntervalId !== null) {
     clearInterval(syncIntervalId);

src/web-server/usage/cliproxy-usage-transformer.ts

@@ -13,10 +13,16 @@ import type { ModelBreakdown, DailyUsage, HourlyUsage, MonthlyUsage } from './ty
 // INTERNAL HELPERS
 // ============================================================================
 
-/** Flat entry pairing a model name with its request detail */
-interface FlatDetail {
+/** Persisted request detail used to rebuild historical CLIProxy analytics buckets */
+export interface CliproxyUsageHistoryDetail {
   model: string;
-  detail: CliproxyRequestDetail;
+  timestamp: string;
+  source: string;
+  authIndex: string;
+  inputTokens: number;
+  outputTokens: number;
+  cacheReadTokens: number;
+  failed: boolean;
 }
 
 /** Accumulator for token counts per model per time bucket */
@@ -36,6 +42,22 @@ function buildModelBreakdown(modelName: string, acc: ModelAccumulator): ModelBre
   return { modelName, inputTokens, outputTokens, cacheCreationTokens: 0, cacheReadTokens, cost };
 }
 
+function createHistoryDetail(
+  model: string,
+  detail: CliproxyRequestDetail
+): CliproxyUsageHistoryDetail {
+  return {
+    model,
+    timestamp: detail.timestamp,
+    source: detail.source,
+    authIndex: String(detail.auth_index),
+    inputTokens: detail.tokens?.input_tokens ?? 0,
+    outputTokens: detail.tokens?.output_tokens ?? 0,
+    cacheReadTokens: detail.tokens?.cached_tokens ?? 0,
+    failed: detail.failed,
+  };
+}
+
 // ============================================================================
 // FLATTEN
 // ============================================================================
@@ -51,14 +73,16 @@ function hasTrackedUsage(detail: CliproxyRequestDetail): boolean {
 
 /**
  * Flatten the nested response.usage.apis[provider].models[model].details[]
- * structure into a flat array. Failed requests are retained only when they
- * still report tracked token usage that analytics can account for.
+ * structure into normalized history details. Failed requests are retained only
+ * when they still report tracked token usage that analytics can account for.
  */
-export function flattenCliproxyDetails(response: CliproxyUsageApiResponse): FlatDetail[] {
+export function extractCliproxyUsageHistoryDetails(
+  response: CliproxyUsageApiResponse
+): CliproxyUsageHistoryDetail[] {
   const apis = response?.usage?.apis;
   if (!apis) return [];
 
-  const results: FlatDetail[] = [];
+  const results: CliproxyUsageHistoryDetail[] = [];
   for (const providerData of Object.values(apis)) {
     const models = providerData?.models;
     if (!models) continue;
@@ -67,20 +91,89 @@ export function flattenCliproxyDetails(response: CliproxyUsageApiResponse): Flat
       if (!details) continue;
       for (const detail of details) {
         if (detail.failed && !hasTrackedUsage(detail)) continue;
-        results.push({ model, detail });
+        results.push(createHistoryDetail(model, detail));
       }
     }
   }
   return results;
 }
 
+function createHistorySignature(detail: CliproxyUsageHistoryDetail): string {
+  return [
+    detail.model,
+    detail.timestamp,
+    detail.source,
+    detail.authIndex,
+    detail.inputTokens,
+    detail.outputTokens,
+    detail.cacheReadTokens,
+    detail.failed ? '1' : '0',
+  ].join('|');
+}
+
+export function mergeCliproxyUsageHistoryDetails(
+  existing: CliproxyUsageHistoryDetail[],
+  incoming: CliproxyUsageHistoryDetail[]
+): CliproxyUsageHistoryDetail[] {
+  const existingCounts = new Map<string, { detail: CliproxyUsageHistoryDetail; count: number }>();
+  for (const detail of existing) {
+    const signature = createHistorySignature(detail);
+    const entry = existingCounts.get(signature);
+    if (entry) {
+      entry.count += 1;
+    } else {
+      existingCounts.set(signature, { detail, count: 1 });
+    }
+  }
+
+  const incomingCounts = new Map<string, { detail: CliproxyUsageHistoryDetail; count: number }>();
+  for (const detail of incoming) {
+    const signature = createHistorySignature(detail);
+    const entry = incomingCounts.get(signature);
+    if (entry) {
+      entry.count += 1;
+    } else {
+      incomingCounts.set(signature, { detail, count: 1 });
+    }
+  }
+
+  for (const [signature, incomingEntry] of incomingCounts) {
+    const existingEntry = existingCounts.get(signature);
+    if (!existingEntry || incomingEntry.count > existingEntry.count) {
+      existingCounts.set(signature, {
+        detail: incomingEntry.detail,
+        count: incomingEntry.count,
+      });
+    }
+  }
+
+  const merged: CliproxyUsageHistoryDetail[] = [];
+  for (const { detail, count } of existingCounts.values()) {
+    for (let index = 0; index < count; index++) {
+      merged.push({ ...detail });
+    }
+  }
+
+  return merged.sort((a, b) => a.timestamp.localeCompare(b.timestamp));
+}
+
+export function pruneCliproxyUsageHistoryDetails(
+  details: CliproxyUsageHistoryDetail[],
+  oldestTimestamp: number
+): CliproxyUsageHistoryDetail[] {
+  return details.filter((detail) => {
+    const timestamp = Date.parse(detail.timestamp);
+    return Number.isFinite(timestamp) && timestamp >= oldestTimestamp;
+  });
+}
+
 // ============================================================================
 // GENERIC AGGREGATOR
 // ============================================================================
 
 /** Group flat details by a time key extractor, return sorted DailyUsage-like records */
 function aggregateByKey<T>(
-  flat: FlatDetail[],
+  flat: CliproxyUsageHistoryDetail[],
   keyFn: (timestamp: string) => string,
   buildRecord: (key: string, breakdowns: ModelBreakdown[], requestCount: number) => T,
   sortFn: (a: T, b: T) => number
@@ -89,18 +182,18 @@ function aggregateByKey<T>(
   const buckets = new Map<string, Map<string, ModelAccumulator>>();
   const requestCounts = new Map<string, number>();
 
-  for (const { model, detail } of flat) {
+  for (const detail of flat) {
     const key = keyFn(detail.timestamp);
     if (!buckets.has(key)) buckets.set(key, new Map());
     requestCounts.set(key, (requestCounts.get(key) ?? 0) + 1);
     const modelMap = buckets.get(key) as Map<string, ModelAccumulator>;
-    if (!modelMap.has(model)) {
-      modelMap.set(model, { inputTokens: 0, outputTokens: 0, cacheReadTokens: 0 });
+    if (!modelMap.has(detail.model)) {
+      modelMap.set(detail.model, { inputTokens: 0, outputTokens: 0, cacheReadTokens: 0 });
     }
-    const acc = modelMap.get(model) as ModelAccumulator;
-    acc.inputTokens += detail.tokens?.input_tokens ?? 0;
-    acc.outputTokens += detail.tokens?.output_tokens ?? 0;
-    acc.cacheReadTokens += detail.tokens?.cached_tokens ?? 0;
+    const acc = modelMap.get(detail.model) as ModelAccumulator;
+    acc.inputTokens += detail.inputTokens;
+    acc.outputTokens += detail.outputTokens;
+    acc.cacheReadTokens += detail.cacheReadTokens;
   }
 
   const records: T[] = [];
@@ -125,7 +218,7 @@ function sumField(breakdowns: ModelBreakdown[], field: keyof ModelBreakdown): nu
 
 /** Transform CLIProxy usage response into DailyUsage array (sorted descending by date) */
 export function transformCliproxyToDailyUsage(response: CliproxyUsageApiResponse): DailyUsage[] {
-  const flat = flattenCliproxyDetails(response);
+  const flat = extractCliproxyUsageHistoryDetails(response);
   return aggregateByKey(
     flat,
     (ts) => ts.slice(0, 10),
@@ -150,7 +243,7 @@ export function transformCliproxyToDailyUsage(response: CliproxyUsageApiResponse
 
 /** Transform CLIProxy usage response into HourlyUsage array (sorted descending by hour) */
 export function transformCliproxyToHourlyUsage(response: CliproxyUsageApiResponse): HourlyUsage[] {
-  const flat = flattenCliproxyDetails(response);
+  const flat = extractCliproxyUsageHistoryDetails(response);
   return aggregateByKey(
     flat,
     (ts) => {
@@ -182,7 +275,7 @@ export function transformCliproxyToHourlyUsage(response: CliproxyUsageApiRespons
 export function transformCliproxyToMonthlyUsage(
   response: CliproxyUsageApiResponse
 ): MonthlyUsage[] {
-  const flat = flattenCliproxyDetails(response);
+  const flat = extractCliproxyUsageHistoryDetails(response);
   return aggregateByKey(
     flat,
     (ts) => ts.slice(0, 7),
@@ -200,3 +293,73 @@ export function transformCliproxyToMonthlyUsage(
     (a, b) => b.month.localeCompare(a.month)
   );
 }
+
+export function buildCliproxyUsageHistoryAggregates(details: CliproxyUsageHistoryDetail[]): {
+  daily: DailyUsage[];
+  hourly: HourlyUsage[];
+  monthly: MonthlyUsage[];
+} {
+  return {
+    daily: aggregateByKey(
+      details,
+      (timestamp) => timestamp.slice(0, 10),
+      (date, breakdowns) => {
+        const totalCost = sumField(breakdowns, 'cost');
+        return {
+          date,
+          source: 'cliproxy',
+          inputTokens: sumField(breakdowns, 'inputTokens'),
+          outputTokens: sumField(breakdowns, 'outputTokens'),
+          cacheCreationTokens: 0,
+          cacheReadTokens: sumField(breakdowns, 'cacheReadTokens'),
+          cost: totalCost,
+          totalCost,
+          modelsUsed: breakdowns.map((breakdown) => breakdown.modelName),
+          modelBreakdowns: breakdowns,
+        };
+      },
+      (a, b) => b.date.localeCompare(a.date)
+    ),
+    hourly: aggregateByKey(
+      details,
+      (timestamp) => {
+        const date = timestamp.slice(0, 10);
+        const hour = timestamp.slice(11, 13) || '00';
+        return `${date} ${hour}:00`;
+      },
+      (hour, breakdowns, requestCount) => {
+        const totalCost = sumField(breakdowns, 'cost');
+        return {
+          hour,
+          source: 'cliproxy',
+          inputTokens: sumField(breakdowns, 'inputTokens'),
+          outputTokens: sumField(breakdowns, 'outputTokens'),
+          cacheCreationTokens: 0,
+          cacheReadTokens: sumField(breakdowns, 'cacheReadTokens'),
+          cost: totalCost,
+          totalCost,
+          modelsUsed: breakdowns.map((breakdown) => breakdown.modelName),
+          modelBreakdowns: breakdowns,
+          requestCount,
+        };
+      },
+      (a, b) => b.hour.localeCompare(a.hour)
+    ),
+    monthly: aggregateByKey(
+      details,
+      (timestamp) => timestamp.slice(0, 7),
+      (month, breakdowns) => ({
+        month,
+        source: 'cliproxy',
+        inputTokens: sumField(breakdowns, 'inputTokens'),
+        outputTokens: sumField(breakdowns, 'outputTokens'),
+        cacheCreationTokens: 0,
+        cacheReadTokens: sumField(breakdowns, 'cacheReadTokens'),
+        totalCost: sumField(breakdowns, 'cost'),
+        modelsUsed: breakdowns.map((breakdown) => breakdown.modelName),
+        modelBreakdowns: breakdowns,
+      }),
+      (a, b) => b.month.localeCompare(a.month)
+    ),
+  };
+}