Expose Arena ELO sync in feature flags (#3821)

Adds ARENA_ELO_SYNC_ENABLED to the Dashboard Feature Flags registry (DB-overridable),
routes Arena ELO startup/status checks through the shared feature-flag resolver while
preserving the existing env fallback, and refreshes env docs (adds the missing
STREAM_READINESS_TIMEOUT_MS example) so env/doc sync stays green.

Integrated into release/v3.8.25.

Co-authored-by: R.D. <rogerproself@gmail.com>

src/i18n/messages/en.json

@@ -843,6 +843,7 @@
     "batchConceptRetentionNote": "Results and error files are retained for 30 days (Anthropic: 29 days)"
   },
   "featureFlagOmnirouteEmergencyFallbackDescription": "Route budget-exhausted requests to the emergency free fallback provider/model.",
+  "featureFlagArenaEloSyncEnabledDescription": "Enable periodic Arena AI leaderboard ELO sync for model intelligence rankings.",
   "sidebar": {
     "home": "Home",
     "dashboard": "Dashboard",
@@ -8720,7 +8721,7 @@
     "subtitle": "Best free providers ranked by model ELO scores from Arena AI leaderboards",
     "loading": "Loading rankings...",
     "errorLoading": "Failed to load rankings",
-    "emptyState": "No rankings available yet. Arena ELO data syncs on startup (daily) — check back shortly, or trigger a manual sync. Set ARENA_ELO_SYNC_ENABLED=false to opt out.",
+    "emptyState": "No rankings available yet. Arena ELO data syncs on startup (daily) — check back shortly, or trigger a manual sync. Disable Arena ELO Sync in Feature Flags or set ARENA_ELO_SYNC_ENABLED=false to opt out.",
     "bestModel": "Best",
     "allCategories": "All Categories",
     "categoryDefault": "Default",

src/instrumentation-node.ts

@@ -265,18 +265,18 @@ export async function registerNodejs(): Promise<void> {
       console.warn("[STARTUP] Auto-refresh daemon failed to start (non-fatal):", msg);
     }
 
-    // Arena ELO sync: model intelligence from the Arena AI leaderboard, powering the
-    // Free Provider Rankings page. On by default (opt out with ARENA_ELO_SYNC_ENABLED=false).
-    // Non-blocking — the initial sync is fire-and-forget and never fatal.
-    if (process.env.ARENA_ELO_SYNC_ENABLED !== "false") {
-      try {
-        const { initArenaEloSync } = await import("@/lib/arenaEloSync");
-        await initArenaEloSync();
+    try {
+      // Arena ELO sync: model intelligence from the Arena AI leaderboard, powering the
+      // Free Provider Rankings page. On by default; configurable from Dashboard Feature Flags.
+      // Non-blocking — the initial sync is fire-and-forget and never fatal.
+      const { initArenaEloSync } = await import("@/lib/arenaEloSync");
+      const started = await initArenaEloSync();
+      if (started) {
         console.log("[STARTUP] Arena ELO sync initialized");
-      } catch (err: unknown) {
-        const msg = err instanceof Error ? err.message : String(err);
-        console.warn("[STARTUP] Arena ELO sync failed to start (non-fatal):", msg);
       }
+    } catch (err: unknown) {
+      const msg = err instanceof Error ? err.message : String(err);
+      console.warn("[STARTUP] Arena ELO sync failed to start (non-fatal):", msg);
     }
 
     // Pricing sync: opt-in external pricing data (self-gated by PRICING_SYNC_ENABLED inside

src/lib/arenaEloSync.ts

@@ -7,9 +7,11 @@
  *
  * Resolution order: user overrides > synced arena ELO > defaults
  *
- * On by default; opt out via ARENA_ELO_SYNC_ENABLED=false.
+ * On by default; opt out via Dashboard Feature Flags or ARENA_ELO_SYNC_ENABLED=false.
  */
 
+import { isArenaEloSyncEnabled } from "@/shared/utils/featureFlags";
+
 import { backupDbFile } from "./db/backup";
 import {
   bulkUpsertModelIntelligence,
@@ -176,6 +178,23 @@ let activeSyncIntervalMs = SYNC_INTERVAL_MS;
 let firstSyncDone = false;
 let syncInProgress = false;
 
+function getErrorMessage(error: unknown): string {
+  return error instanceof Error ? error.message : String(error);
+}
+
+function getEffectiveArenaEloSyncEnabled(): boolean {
+  try {
+    return isArenaEloSyncEnabled();
+  } catch (error) {
+    console.warn(
+      `[ARENA_ELO_SYNC] Failed to resolve ARENA_ELO_SYNC_ENABLED feature flag: ${getErrorMessage(
+        error
+      )}`
+    );
+    return process.env.ARENA_ELO_SYNC_ENABLED !== "false";
+  }
+}
+
 // ─── Model name normalization ────────────────────────────
 
 /**
@@ -507,7 +526,7 @@ export function stopArenaEloSync(): void {
  *   next scheduled sync time, interval, and active sources.
  */
 export function getArenaEloSyncStatus(): SyncStatus {
-  const enabled = process.env.ARENA_ELO_SYNC_ENABLED !== "false";
+  const enabled = getEffectiveArenaEloSyncEnabled();
   return {
     enabled,
     lastSync: lastSyncTime,
@@ -524,21 +543,23 @@ export function getArenaEloSyncStatus(): SyncStatus {
 // ─── Init (called from server-init.ts) ───────────────────
 
 /**
- * Initialize Arena ELO sync if enabled via environment variable.
+ * Initialize Arena ELO sync if enabled via feature flag configuration.
  *
- * Reads `ARENA_ELO_SYNC_ENABLED` (default: true; set to `false` to opt out).
+ * Reads `ARENA_ELO_SYNC_ENABLED` (default: true; set to `false` to opt out)
+ * through the feature flag resolver, so DB overrides from the dashboard apply.
  * When enabled, starts periodic sync with the interval from `ARENA_ELO_SYNC_INTERVAL`
  * (default: 86400 seconds / daily).
  *
  * All errors during initialization or the initial sync are caught and logged
  * — initialization is never fatal.
  */
-export async function initArenaEloSync(): Promise<void> {
-  if (process.env.ARENA_ELO_SYNC_ENABLED === "false") {
+export async function initArenaEloSync(): Promise<boolean> {
+  if (!getEffectiveArenaEloSyncEnabled()) {
     console.log(
-      "[ARENA_ELO_SYNC] Disabled (ARENA_ELO_SYNC_ENABLED=false). Unset or =true to enable."
+      "[ARENA_ELO_SYNC] Disabled by the effective ARENA_ELO_SYNC_ENABLED feature flag. Enable it from Dashboard Feature Flags, unset the env var, or set it to true to enable."
     );
-    return;
+    return false;
   }
   startPeriodicSync();
+  return true;
 }

src/server-init.ts

@@ -133,14 +133,12 @@ async function startServer() {
   }
 
   // Arena ELO sync: model intelligence from leaderboard data (non-blocking, never fatal).
-  // On by default; opt out with ARENA_ELO_SYNC_ENABLED=false.
-  if (process.env.ARENA_ELO_SYNC_ENABLED !== "false") {
-    try {
-      const { initArenaEloSync } = await import("./lib/arenaEloSync");
-      await initArenaEloSync();
-    } catch (err) {
-      startupLog.warn({ error: getErrorMessage(err) }, "Arena ELO sync could not initialize");
-    }
+  // On by default; opt out with Dashboard Feature Flags or ARENA_ELO_SYNC_ENABLED=false.
+  try {
+    const { initArenaEloSync } = await import("./lib/arenaEloSync");
+    await initArenaEloSync();
+  } catch (err) {
+    startupLog.warn({ error: getErrorMessage(err) }, "Arena ELO sync could not initialize");
   }
 }
 

src/shared/constants/featureFlagDefinitions.ts

@@ -199,7 +199,7 @@ export const FEATURE_FLAG_DEFINITIONS: FeatureFlagDefinition[] = [
     warningLevel: "info",
   },
 
-  // ──────────────── Runtime (9) ────────────────
+  // ──────────────── Runtime (10) ────────────────
   {
     key: "OMNIROUTE_MCP_ENFORCE_SCOPES",
     label: "MCP Enforce Scopes",
@@ -302,6 +302,17 @@ export const FEATURE_FLAG_DEFINITIONS: FeatureFlagDefinition[] = [
     requiresRestart: false,
     warningLevel: "info",
   },
+  {
+    key: "ARENA_ELO_SYNC_ENABLED",
+    label: "Arena ELO Sync",
+    description: "Enable periodic Arena AI leaderboard ELO sync for model intelligence rankings.",
+    descriptionI18nKey: "featureFlagArenaEloSyncEnabledDescription",
+    category: "runtime",
+    defaultValue: "true",
+    type: "boolean",
+    requiresRestart: false,
+    warningLevel: "info",
+  },
 
   // ──────────────── CLI (3) ────────────────
   {

src/shared/utils/featureFlags.ts

@@ -75,3 +75,7 @@ export function isCcCompatibleProviderEnabled(): boolean {
 export function isModelCatalogNamesEnabled(): boolean {
   return isFeatureFlagEnabled("MODEL_CATALOG_INCLUDE_NAMES");
 }
+
+export function isArenaEloSyncEnabled(): boolean {
+  return isFeatureFlagEnabled("ARENA_ELO_SYNC_ENABLED");
+}