[verified] fix: normalize analytics skill payloads

Normalize /api/analytics/usage responses so older backends that omit
skill analytics do not crash the dashboard.

- add normalizeAnalyticsResponse at the API boundary
- type the page state against the normalized payload
- cover missing and populated skill payloads with tests

web/src/lib/api.analytics.test.ts

@@ -0,0 +1,74 @@
+/// <reference types="node" />
+
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { normalizeAnalyticsResponse, type AnalyticsResponse } from "./api.ts";
+
+test("normalizeAnalyticsResponse fills in missing skill analytics for older backends", () => {
+  const raw = {
+    daily: [],
+    by_model: [],
+    totals: {
+      total_input: 0,
+      total_output: 0,
+      total_cache_read: 0,
+      total_reasoning: 0,
+      total_estimated_cost: 0,
+      total_actual_cost: 0,
+      total_sessions: 0,
+      total_api_calls: 0,
+    },
+  } as AnalyticsResponse;
+
+  const normalized = normalizeAnalyticsResponse(raw);
+
+  assert.deepEqual(normalized.skills, {
+    summary: {
+      total_skill_loads: 0,
+      total_skill_edits: 0,
+      total_skill_actions: 0,
+      distinct_skills_used: 0,
+    },
+    top_skills: [],
+  });
+});
+
+test("normalizeAnalyticsResponse preserves populated skill analytics", () => {
+  const raw: AnalyticsResponse = {
+    daily: [],
+    by_model: [],
+    totals: {
+      total_input: 0,
+      total_output: 0,
+      total_cache_read: 0,
+      total_reasoning: 0,
+      total_estimated_cost: 0,
+      total_actual_cost: 0,
+      total_sessions: 0,
+      total_api_calls: 0,
+    },
+    skills: {
+      summary: {
+        total_skill_loads: 2,
+        total_skill_edits: 1,
+        total_skill_actions: 3,
+        distinct_skills_used: 2,
+      },
+      top_skills: [
+        {
+          skill: "systematic-debugging",
+          view_count: 2,
+          manage_count: 1,
+          total_count: 3,
+          percentage: 100,
+          last_used_at: 1713900000,
+        },
+      ],
+    },
+  };
+
+  const normalized = normalizeAnalyticsResponse(raw);
+
+  assert.deepEqual(normalized.skills, raw.skills);
+});

web/src/lib/api.ts

@@ -52,8 +52,8 @@ export const api = {
     if (params.component && params.component !== "all") qs.set("component", params.component);
     return fetchJSON<LogsResponse>(`/api/logs?${qs.toString()}`);
   },
-  getAnalytics: (days: number) =>
-    fetchJSON<AnalyticsResponse>(`/api/analytics/usage?days=${days}`),
+  getAnalytics: (days: number): Promise<NormalizedAnalyticsResponse> =>
+    fetchJSON<AnalyticsResponse>(`/api/analytics/usage?days=${days}`).then(normalizeAnalyticsResponse),
   getConfig: () => fetchJSON<Record<string, unknown>>("/api/config"),
   getDefaults: () => fetchJSON<Record<string, unknown>>("/api/config/defaults"),
   getSchema: () => fetchJSON<{ fields: Record<string, unknown>; category_order: string[] }>("/api/config/schema"),
@@ -355,10 +355,32 @@ export interface AnalyticsResponse {
     total_sessions: number;
     total_api_calls: number;
   };
+  skills?: {
+    summary?: AnalyticsSkillsSummary;
+    top_skills?: AnalyticsSkillEntry[];
+  };
+}
+
+export type NormalizedAnalyticsResponse = Omit<AnalyticsResponse, "skills"> & {
   skills: {
     summary: AnalyticsSkillsSummary;
     top_skills: AnalyticsSkillEntry[];
   };
+};
+
+export function normalizeAnalyticsResponse(raw: AnalyticsResponse): NormalizedAnalyticsResponse {
+  return {
+    ...raw,
+    skills: {
+      summary: {
+        total_skill_loads: raw.skills?.summary?.total_skill_loads ?? 0,
+        total_skill_edits: raw.skills?.summary?.total_skill_edits ?? 0,
+        total_skill_actions: raw.skills?.summary?.total_skill_actions ?? 0,
+        distinct_skills_used: raw.skills?.summary?.distinct_skills_used ?? 0,
+      },
+      top_skills: Array.isArray(raw.skills?.top_skills) ? raw.skills.top_skills : [],
+    },
+  };
 }
 
 export interface CronJob {

web/src/pages/AnalyticsPage.tsx

@@ -7,7 +7,12 @@ import {
   TrendingUp,
 } from "lucide-react";
 import { api } from "@/lib/api";
-import type { AnalyticsResponse, AnalyticsDailyEntry, AnalyticsModelEntry, AnalyticsSkillEntry } from "@/lib/api";
+import type {
+  AnalyticsDailyEntry,
+  AnalyticsModelEntry,
+  AnalyticsSkillEntry,
+  NormalizedAnalyticsResponse,
+} from "@/lib/api";
 import { timeAgo } from "@/lib/utils";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Button } from "@/components/ui/button";
@@ -277,7 +282,7 @@ function SkillTable({ skills }: { skills: AnalyticsSkillEntry[] }) {
 
 export default function AnalyticsPage() {
   const [days, setDays] = useState(30);
-  const [data, setData] = useState<AnalyticsResponse | null>(null);
+  const [data, setData] = useState<NormalizedAnalyticsResponse | null>(null);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
   const { t } = useI18n();