diff --git a/Dockerfile b/Dockerfile
index 3e3331a5df..135c6abceb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -57,7 +57,8 @@ LABEL org.opencontainers.image.title="omniroute" \
 ENV NODE_ENV=production
 ENV PORT=20128
 ENV HOSTNAME=0.0.0.0
-ENV NODE_OPTIONS="--max-old-space-size=256"
+ENV OMNIROUTE_MEMORY_MB=1024
+ENV NODE_OPTIONS="--max-old-space-size=${OMNIROUTE_MEMORY_MB}"
 
 # Data directory inside Docker — must match the volume mount in docker-compose.yml
 ENV DATA_DIR=/app/data
diff --git a/open-sse/config/providerRegistry.ts b/open-sse/config/providerRegistry.ts
index f857287ff4..e121fc077a 100644
--- a/open-sse/config/providerRegistry.ts
+++ b/open-sse/config/providerRegistry.ts
@@ -580,7 +580,7 @@ function mapStainlessArch() {
 
 // ── Registry ──────────────────────────────────────────────────────────────
 
-export const REGISTRY: Record<string, RegistryEntry> = {
+const _REGISTRY_EAGER: Record<string, RegistryEntry> = {
   // ─── OAuth Providers ───────────────────────────────────────────────────
   kie: {
     id: "kie",
@@ -4248,12 +4248,14 @@ export const REGISTRY: Record<string, RegistryEntry> = {
   },
 };
 
+export const REGISTRY: Record<string, RegistryEntry> = _REGISTRY_EAGER;
+
 // ── Generator Functions ───────────────────────────────────────────────────
 
 /** Generate legacy PROVIDERS object shape for constants.js backward compatibility */
 export function generateLegacyProviders(): Record<string, LegacyProvider> {
   const providers: Record<string, LegacyProvider> = {};
-  for (const [id, entry] of Object.entries(REGISTRY)) {
+  for (const [id, entry] of Object.entries(_REGISTRY_EAGER)) {
     const p: LegacyProvider = { format: entry.format };
 
     // URL(s)
@@ -4307,7 +4309,7 @@ export function generateLegacyProviders(): Record<string, LegacyProvider> {
 /** Generate PROVIDER_MODELS map (alias → model list) */
 export function generateModels(): Record<string, RegistryModel[]> {
   const models: Record<string, RegistryModel[]> = {};
-  for (const entry of Object.values(REGISTRY)) {
+  for (const entry of Object.values(_REGISTRY_EAGER)) {
     if (entry.models && entry.models.length > 0) {
       const key = entry.alias || entry.id;
       // If alias already exists, don't overwrite (first wins)
@@ -4322,7 +4324,7 @@ export function generateModels(): Record<string, RegistryModel[]> {
 /** Generate PROVIDER_ID_TO_ALIAS map */
 export function generateAliasMap(): Record<string, string> {
   const map: Record<string, string> = {};
-  for (const entry of Object.values(REGISTRY)) {
+  for (const entry of Object.values(_REGISTRY_EAGER)) {
     map[entry.id] = entry.alias || entry.id;
   }
   return map;
@@ -4364,33 +4366,40 @@ export function isLocalProvider(baseUrl?: string | null): boolean {
 }
 
 /** Set of provider IDs with passthroughModels enabled — 404s are model-specific, not account-level. */
-const _passthroughProviderIds: Set<string> | null = (() => {
+let _passthroughProviderIds: Set<string> | null = null;
+function ensurePassthroughProviderIds(): Set<string> {
+  if (_passthroughProviderIds) return _passthroughProviderIds;
   try {
     const ids = new Set<string>();
-    for (const entry of Object.values(REGISTRY)) {
+    for (const entry of Object.values(_REGISTRY_EAGER)) {
       if (entry.passthroughModels) ids.add(entry.id);
     }
-    return ids;
+    _passthroughProviderIds = ids;
   } catch {
-    return null;
+    _passthroughProviderIds = new Set<string>();
   }
-})();
-
+  return _passthroughProviderIds;
+}
 export function getPassthroughProviders(): Set<string> {
-  return _passthroughProviderIds ?? new Set<string>();
+  return ensurePassthroughProviderIds();
 }
 
 // ── Registry Lookup Helpers ───────────────────────────────────────────────
 
 const _byAlias = new Map<string, RegistryEntry>();
-for (const entry of Object.values(REGISTRY)) {
-  if (entry.alias && entry.alias !== entry.id) {
-    _byAlias.set(entry.alias, entry);
+let _byAliasPopulated = false;
+function ensureByAliasPopulated(): void {
+  if (_byAliasPopulated) return;
+  _byAliasPopulated = true;
+  for (const entry of Object.values(_REGISTRY_EAGER)) {
+    if (entry.alias && entry.alias !== entry.id) {
+      _byAlias.set(entry.alias, entry);
+    }
   }
 }
-
 /** Get registry entry by provider ID or alias */
 export function getRegistryEntry(provider: string): RegistryEntry | null {
+  ensureByAliasPopulated();
   return REGISTRY[provider] || _byAlias.get(provider) || null;
 }
 
@@ -4402,10 +4411,15 @@ export function getRegisteredProviders(): string[] {
 // Precomputed map: modelId → unsupportedParams (O(1) lookup instead of O(N×M) scan).
 // Built once at module load from all registry entries.
 const _unsupportedParamsMap = new Map<string, readonly string[]>();
-for (const entry of Object.values(REGISTRY)) {
-  for (const model of entry.models) {
-    if (model.unsupportedParams && !_unsupportedParamsMap.has(model.id)) {
-      _unsupportedParamsMap.set(model.id, model.unsupportedParams);
+let _unsupportedParamsPopulated = false;
+function ensureUnsupportedParamsPopulated(): void {
+  if (_unsupportedParamsPopulated) return;
+  _unsupportedParamsPopulated = true;
+  for (const entry of Object.values(_REGISTRY_EAGER)) {
+    for (const model of entry.models) {
+      if (model.unsupportedParams && !_unsupportedParamsMap.has(model.id)) {
+        _unsupportedParamsMap.set(model.id, model.unsupportedParams);
+      }
     }
   }
 }
@@ -4417,6 +4431,7 @@ for (const entry of Object.values(REGISTRY)) {
  * Returns empty array if no restrictions are defined.
  */
 export function getUnsupportedParams(provider: string, modelId: string): readonly string[] {
+  ensureUnsupportedParamsPopulated();
   // 1. Check current provider's registry (exact match)
   const entry = getRegistryEntry(provider);
   const modelEntry = entry?.models.find((m) => m.id === modelId);
diff --git a/open-sse/services/comboMetrics.ts b/open-sse/services/comboMetrics.ts
index 6e33aafdb2..6c6e8e71da 100644
--- a/open-sse/services/comboMetrics.ts
+++ b/open-sse/services/comboMetrics.ts
@@ -188,6 +188,40 @@ function toMetricView<T extends ModelMetrics>(
 // In-memory store
 const metrics = new Map<string, ComboMetricsEntry>();
 const shadowMetrics = new Map<string, ComboShadowMetricsEntry>();
+const MAX_METRICS_ENTRIES = 500;
+const METRICS_TTL_MS = 60 * 60 * 1000; // 1 hour
+
+function evictOldestMetric(targetMap: Map<string, { lastUsedAt: string | null }>): void {
+  let oldest: string | null = null;
+  let oldestTime = Infinity;
+  for (const [name, entry] of targetMap) {
+    const t = entry.lastUsedAt ? new Date(entry.lastUsedAt).getTime() : Date.now();
+    if (t < oldestTime) { oldestTime = t; oldest = name; }
+  }
+  if (oldest) {
+    metrics.delete(oldest);
+    shadowMetrics.delete(oldest);
+  }
+}
+
+const _metricsCleanupTimer = setInterval(() => {
+  const now = Date.now();
+  for (const [name, entry] of metrics) {
+    const lastUsed = entry.lastUsedAt ? new Date(entry.lastUsedAt).getTime() : now;
+    if (now - lastUsed > METRICS_TTL_MS) {
+      metrics.delete(name);
+      shadowMetrics.delete(name);
+    }
+  }
+  for (const [name, entry] of shadowMetrics) {
+    const lastUsed = entry.lastUsedAt ? new Date(entry.lastUsedAt).getTime() : now;
+    if (now - lastUsed > METRICS_TTL_MS) {
+      metrics.delete(name);
+      shadowMetrics.delete(name);
+    }
+  }
+}, 5 * 60 * 1000); // every 5 minutes
+_metricsCleanupTimer.unref?.(); // Don't prevent process exit
 
 /**
  * Record a combo request result.
@@ -217,6 +251,9 @@ export function recordComboRequest(
     target?: ComboRequestTargetMeta | null;
   }
 ): void {
+  if (!metrics.has(comboName) && metrics.size >= MAX_METRICS_ENTRIES) {
+    evictOldestMetric(metrics);
+  }
   if (!metrics.has(comboName)) {
     metrics.set(comboName, createComboEntry(strategy));
   }
@@ -283,6 +320,9 @@ export function recordComboShadowRequest(
     target?: ComboRequestTargetMeta | null;
   }
 ): void {
+  if (!shadowMetrics.has(comboName) && shadowMetrics.size >= MAX_METRICS_ENTRIES) {
+    evictOldestMetric(shadowMetrics);
+  }
   if (!shadowMetrics.has(comboName)) {
     shadowMetrics.set(comboName, createShadowEntry());
   }
@@ -396,6 +436,9 @@ export function getAllComboMetrics(): Record<string, ComboMetricsView | null> {
  * Record detected prompt intent for a combo (used by multilingual routing analytics).
  */
 export function recordComboIntent(comboName: string, intent: string): void {
+  if (!metrics.has(comboName) && metrics.size >= MAX_METRICS_ENTRIES) {
+    evictOldestMetric(metrics);
+  }
   if (!metrics.has(comboName)) {
     metrics.set(comboName, createComboEntry("priority"));
   }
@@ -418,6 +461,7 @@ export function resetComboMetrics(comboName: string): void {
  * Reset all combo metrics.
  */
 export function resetAllComboMetrics(): void {
+  clearInterval(_metricsCleanupTimer);
   metrics.clear();
   shadowMetrics.clear();
 }
diff --git a/open-sse/services/usage.ts b/open-sse/services/usage.ts
index 1f3cade0f6..1e8401c7a4 100644
--- a/open-sse/services/usage.ts
+++ b/open-sse/services/usage.ts
@@ -1821,6 +1821,28 @@ const _antigravityAvailableModelsInflight = new Map<string, Promise<unknown>>();
 const _antigravityCreditProbeCache = new Map<string, { data: number | null; fetchedAt: number }>();
 const _antigravityCreditProbeInflight = new Map<string, Promise<number | null>>();
 
+// ── Proactive TTL purging for module-level caches ──────────────────────────
+// All 4 data caches only evict on read (passive TTL). This interval proactively
+// purges stale entries so keys accessed once and never again don't leak memory.
+// The 2 inflight Maps (availableModelsInflight, creditProbeInflight) self-clean
+// when the Promise resolves/rejects, so they are NOT touched here.
+const _usageCacheCleanupTimer = setInterval(() => {
+  const now = Date.now();
+  for (const [key, entry] of _geminiCliSubCache) {
+    if (now - entry.fetchedAt > GEMINI_CLI_CACHE_TTL_MS) _geminiCliSubCache.delete(key);
+  }
+  for (const [key, entry] of _antigravitySubCache) {
+    if (now - entry.fetchedAt > ANTIGRAVITY_CACHE_TTL_MS) _antigravitySubCache.delete(key);
+  }
+  for (const [key, entry] of _antigravityAvailableModelsCache) {
+    if (now - entry.fetchedAt > ANTIGRAVITY_MODELS_CACHE_TTL_MS) _antigravityAvailableModelsCache.delete(key);
+  }
+  for (const [key, entry] of _antigravityCreditProbeCache) {
+    if (now - entry.fetchedAt > ANTIGRAVITY_CREDIT_PROBE_TTL_MS) _antigravityCreditProbeCache.delete(key);
+  }
+}, 5 * 60 * 1000); // every 5 minutes
+_usageCacheCleanupTimer.unref?.(); // Don't prevent process exit
+
 interface AntigravityUsageOptions {
   forceRefresh?: boolean;
 }
diff --git a/scripts/check-permissions.sh b/scripts/check-permissions.sh
index 13eedf45b0..88e2dba4bc 100755
--- a/scripts/check-permissions.sh
+++ b/scripts/check-permissions.sh
@@ -1,6 +1,13 @@
 #!/bin/sh
 set -e
 
+# ── Memory limit override ──────────────────────────────────────────────
+# If OMNIROUTE_MEMORY_MB is set, build NODE_OPTIONS dynamically so the
+# user can tune heap size via environment without editing the Dockerfile.
+if [ -n "$OMNIROUTE_MEMORY_MB" ]; then
+  export NODE_OPTIONS="${NODE_OPTIONS:-} --max-old-space-size=${OMNIROUTE_MEMORY_MB}"
+fi
+
 if [ -d "/app/data" ] && [ ! -w "/app/data" ]; then
     echo "WARNING: /app/data is not writable by the current user (UID $(id -u))."
     echo "Run this on the Docker host to fix:"
diff --git a/tests/unit/services/combo-metrics-memory.test.ts b/tests/unit/services/combo-metrics-memory.test.ts
new file mode 100644
index 0000000000..bc6b2390f9
--- /dev/null
+++ b/tests/unit/services/combo-metrics-memory.test.ts
@@ -0,0 +1,276 @@
+/**
+ * Tests for comboMetrics memory management — eviction and TTL behavior.
+ *
+ * Verifies that:
+ * - Recording and retrieval work correctly
+ * - MAX_METRICS_ENTRIES (500) cap is enforced via eviction of oldest entries
+ * - Shadow metrics are isolated from production metrics
+ * - resetComboMetrics and resetAllComboMetrics clear state correctly
+ * - getAllComboMetrics returns all entries
+ * - recordComboIntent tracks intent counts
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const mod = await import("../../../open-sse/services/comboMetrics.ts");
+const {
+  recordComboRequest,
+  recordComboShadowRequest,
+  getComboMetrics,
+  getAllComboMetrics,
+  resetComboMetrics,
+  resetAllComboMetrics,
+  recordComboIntent,
+} = mod;
+
+// Reset all state before each test group to avoid cross-test pollution.
+resetAllComboMetrics();
+
+// ─── Basic record + retrieve ────────────────────────────────────────────────
+
+test("recordComboRequest: basic recording and retrieval", () => {
+  resetAllComboMetrics();
+  recordComboRequest("test-combo", "gpt-4", {
+    success: true,
+    latencyMs: 100,
+  });
+  const metrics = getComboMetrics("test-combo");
+  assert.ok(metrics, "metrics should exist for recorded combo");
+  assert.equal(metrics.totalRequests, 1, "should have 1 total request");
+  assert.equal(metrics.totalSuccesses, 1, "should have 1 success");
+  assert.equal(metrics.totalFailures, 0, "should have 0 failures");
+  assert.equal(metrics.successRate, 100, "success rate should be 100%");
+  assert.equal(metrics.avgLatencyMs, 100, "avg latency should be 100ms");
+});
+
+test("recordComboRequest: tracks per-model metrics", () => {
+  resetAllComboMetrics();
+  recordComboRequest("combo-1", "gpt-4", { success: true, latencyMs: 100 });
+  recordComboRequest("combo-1", "claude-3", { success: false, latencyMs: 200 });
+  const metrics = getComboMetrics("combo-1");
+  assert.ok(metrics);
+  assert.equal(metrics.totalRequests, 2, "should have 2 total requests");
+  assert.equal(metrics.successRate, 50, "success rate should be 50%");
+  assert.ok(metrics.byModel["gpt-4"], "should have gpt-4 model metrics");
+  assert.ok(metrics.byModel["claude-3"], "should have claude-3 model metrics");
+  assert.equal(metrics.byModel["gpt-4"].successRate, 100);
+  assert.equal(metrics.byModel["claude-3"].successRate, 0);
+});
+
+test("recordComboRequest: handles null model string gracefully", () => {
+  resetAllComboMetrics();
+  recordComboRequest("combo-null", null, { success: true, latencyMs: 50 });
+  const metrics = getComboMetrics("combo-null");
+  assert.ok(metrics, "metrics should exist even with null model");
+  assert.equal(metrics.totalRequests, 1);
+  // null model should not create per-model entries
+  assert.equal(Object.keys(metrics.byModel).length, 0, "should have no model entries");
+});
+
+test("recordComboRequest: tracks fallback count", () => {
+  resetAllComboMetrics();
+  recordComboRequest("combo-fb", "gpt-4", {
+    success: true,
+    latencyMs: 200,
+    fallbackCount: 2,
+  });
+  const metrics = getComboMetrics("combo-fb");
+  assert.ok(metrics);
+  assert.equal(metrics.totalFallbacks, 2, "should track 2 fallbacks");
+  // fallbackRate = (totalFallbacks / totalRequests) * 100 = (2/1) * 100 = 200
+  assert.equal(metrics.fallbackRate, 200, "fallback rate should be 200% (2 fallbacks on 1 request)");
+});
+
+// ─── getComboMetrics returns null for unknown combos ─────────────────────────
+
+test("getComboMetrics: returns null for unknown combo", () => {
+  const metrics = getComboMetrics("nonexistent-combo-xyz");
+  assert.equal(metrics, null, "unknown combo should return null");
+});
+
+// ─── resetComboMetrics ───────────────────────────────────────────────────────
+
+test("resetComboMetrics: clears a specific combo", () => {
+  resetAllComboMetrics();
+  recordComboRequest("to-keep", "gpt-4", { success: true, latencyMs: 100 });
+  recordComboRequest("to-reset", "gpt-4", { success: true, latencyMs: 100 });
+  resetComboMetrics("to-reset");
+  assert.ok(getComboMetrics("to-keep"), "to-keep should still exist");
+  assert.equal(getComboMetrics("to-reset"), null, "to-reset should be cleared");
+});
+
+// ─── resetAllComboMetrics ────────────────────────────────────────────────────
+
+test("resetAllComboMetrics: clears all production and shadow metrics", () => {
+  recordComboRequest("combo-a", "gpt-4", { success: true, latencyMs: 100 });
+  recordComboShadowRequest("shadow-a", "gpt-4", { success: true, latencyMs: 100 });
+  assert.ok(getComboMetrics("combo-a"), "combo-a should exist before reset");
+  assert.ok(getComboMetrics("shadow-a"), "shadow-a should exist before reset");
+  resetAllComboMetrics();
+  assert.equal(getComboMetrics("combo-a"), null, "combo-a should be cleared");
+  assert.equal(getComboMetrics("shadow-a"), null, "shadow-a should be cleared");
+});
+
+// ─── getAllComboMetrics ───────────────────────────────────────────────────────
+
+test("getAllComboMetrics: returns all production and shadow entries", () => {
+  resetAllComboMetrics();
+  recordComboRequest("combo-x", "gpt-4", { success: true, latencyMs: 100 });
+  recordComboRequest("combo-y", "claude-3", { success: false, latencyMs: 200 });
+  recordComboShadowRequest("shadow-x", "gpt-4", { success: true, latencyMs: 150 });
+  const all = getAllComboMetrics();
+  assert.ok(all["combo-x"], "should include combo-x");
+  assert.ok(all["combo-y"], "should include combo-y");
+  assert.ok(all["shadow-x"], "should include shadow-x from shadow metrics");
+});
+
+// ─── Shadow metrics ──────────────────────────────────────────────────────────
+
+test("recordComboShadowRequest: tracks shadow metrics separately from production", () => {
+  resetAllComboMetrics();
+  recordComboRequest("prod-combo", "gpt-4", { success: true, latencyMs: 100 });
+  recordComboShadowRequest("prod-combo", "claude-3", { success: false, latencyMs: 200 });
+  const metrics = getComboMetrics("prod-combo");
+  assert.ok(metrics);
+  // Production sees only gpt-4
+  assert.equal(metrics.totalRequests, 1, "production should have 1 request");
+  assert.equal(metrics.successRate, 100, "production success rate should be 100%");
+  // Shadow is separate
+  assert.ok(metrics.shadow, "shadow metrics should be present");
+  assert.equal(metrics.shadow.totalRequests, 1, "shadow should have 1 request");
+  assert.equal(metrics.shadow.successRate, 0, "shadow success rate should be 0%");
+});
+
+test("recordComboShadowRequest: shadow-only combo returns in getAllComboMetrics", () => {
+  resetAllComboMetrics();
+  recordComboShadowRequest("shadow-only", "gpt-4", { success: true, latencyMs: 50 });
+  const all = getAllComboMetrics();
+  assert.ok(all["shadow-only"], "shadow-only combo should appear in getAllComboMetrics");
+});
+
+// ─── recordComboIntent ───────────────────────────────────────────────────────
+
+test("recordComboIntent: tracks intent counts on existing combo", () => {
+  resetAllComboMetrics();
+  recordComboRequest("intent-combo", "gpt-4", { success: true, latencyMs: 100 });
+  recordComboIntent("intent-combo", "chat");
+  recordComboIntent("intent-combo", "chat");
+  recordComboIntent("intent-combo", "code");
+  const metrics = getComboMetrics("intent-combo");
+  assert.ok(metrics);
+  assert.equal(metrics.intentCounts["chat"], 2, "should count 2 chat intents");
+  assert.equal(metrics.intentCounts["code"], 1, "should count 1 code intent");
+});
+
+test("recordComboIntent: creates combo entry if not yet recorded", () => {
+  resetAllComboMetrics();
+  recordComboIntent("new-intent-combo", "search");
+  const metrics = getComboMetrics("new-intent-combo");
+  assert.ok(metrics, "combo should be created by recordComboIntent");
+  assert.equal(metrics.intentCounts["search"], 1);
+});
+
+// ─── Eviction: MAX_METRICS_ENTRIES cap ───────────────────────────────────────
+
+test("eviction: inserting a new combo at capacity evicts the oldest entry", () => {
+  resetAllComboMetrics();
+  const MAX = 500;
+  // Fill to capacity with unique combos
+  for (let i = 0; i < MAX; i++) {
+    recordComboRequest(`fill-${i}`, "gpt-4", { success: true, latencyMs: 10 });
+  }
+  // All 500 should be present
+  assert.ok(getComboMetrics("fill-0"), "first inserted combo should exist at capacity");
+  assert.ok(getComboMetrics(`fill-${MAX - 1}`), "last inserted combo should exist at capacity");
+
+  // Insert one more — should trigger eviction of the oldest entry
+  recordComboRequest("new-after-capacity", "gpt-4", { success: true, latencyMs: 50 });
+  const all = getAllComboMetrics();
+  const totalProduction = Object.keys(all).filter((k) => {
+    const m = all[k];
+    return m && m.totalRequests > 0;
+  }).length;
+  // Map size should not exceed MAX (the new one replaced the oldest)
+  assert.ok(totalProduction <= MAX, `production combos (${totalProduction}) should not exceed cap (${MAX})`);
+  assert.ok(
+    getComboMetrics("new-after-capacity"),
+    "newly inserted combo should exist after eviction"
+  );
+});
+
+test("eviction: shadow metrics respect their own MAX_METRICS_ENTRIES cap", () => {
+  resetAllComboMetrics();
+  const MAX = 500;
+  // Fill shadow metrics to capacity
+  for (let i = 0; i < MAX; i++) {
+    recordComboShadowRequest(`shadow-fill-${i}`, "gpt-4", {
+      success: true,
+      latencyMs: 10,
+    });
+  }
+  assert.ok(
+    getComboMetrics("shadow-fill-0"),
+    "first shadow combo should exist at capacity"
+  );
+
+  // Insert one more shadow — should trigger eviction
+  recordComboShadowRequest("shadow-after-capacity", "gpt-4", {
+    success: true,
+    latencyMs: 50,
+  });
+  assert.ok(
+    getComboMetrics("shadow-after-capacity"),
+    "newly inserted shadow combo should exist after eviction"
+  );
+});
+
+test("eviction: recordComboIntent respects MAX_METRICS_ENTRIES cap", () => {
+  resetAllComboMetrics();
+  const MAX = 500;
+  // Fill production metrics to capacity
+  for (let i = 0; i < MAX; i++) {
+    recordComboRequest(`intent-fill-${i}`, "gpt-4", { success: true, latencyMs: 10 });
+  }
+  // Adding intent for a NEW combo should trigger eviction
+  recordComboIntent("intent-after-capacity", "chat");
+  assert.ok(
+    getComboMetrics("intent-after-capacity"),
+    "newly created intent combo should exist after eviction"
+  );
+});
+
+test("eviction: updating an existing combo at capacity does NOT evict", () => {
+  resetAllComboMetrics();
+  const MAX = 500;
+  // Fill to capacity
+  for (let i = 0; i < MAX; i++) {
+    recordComboRequest(`update-${i}`, "gpt-4", { success: true, latencyMs: 10 });
+  }
+  // Update an existing combo — should NOT trigger eviction since it's not a new key
+  recordComboRequest("update-0", "gpt-4", { success: false, latencyMs: 50 });
+  const metrics = getComboMetrics("update-0");
+  assert.ok(metrics, "updated combo should still exist");
+  assert.equal(metrics.totalRequests, 2, "updated combo should have 2 requests");
+});
+
+// ─── Strategy tracking ───────────────────────────────────────────────────────
+
+test("recordComboRequest: stores the routing strategy", () => {
+  resetAllComboMetrics();
+  recordComboRequest("strat-combo", "gpt-4", {
+    success: true,
+    latencyMs: 100,
+    strategy: "weighted",
+  });
+  const metrics = getComboMetrics("strat-combo");
+  assert.ok(metrics);
+  assert.equal(metrics.strategy, "weighted", "should store the strategy");
+});
+
+test("recordComboRequest: defaults strategy to 'priority'", () => {
+  resetAllComboMetrics();
+  recordComboRequest("default-strat", "gpt-4", { success: true, latencyMs: 100 });
+  const metrics = getComboMetrics("default-strat");
+  assert.ok(metrics);
+  assert.equal(metrics.strategy, "priority", "default strategy should be 'priority'");
+});