diff --git a/open-sse/handlers/chatCore.ts b/open-sse/handlers/chatCore.ts
index c60b379a0e..5c3312ab87 100644
--- a/open-sse/handlers/chatCore.ts
+++ b/open-sse/handlers/chatCore.ts
@@ -950,11 +950,24 @@ export async function handleChatCore({
 
   const executeProviderRequest = async (modelToCall = effectiveModel, allowDedup = false) => {
     const execute = async () => {
-      const bodyToSend =
+      let bodyToSend =
         translatedBody.model === modelToCall
           ? translatedBody
           : { ...translatedBody, model: modelToCall };
 
+      // Inject prompt_cache_key for OpenAI providers if not already set
+      if (
+        targetFormat === FORMATS.OPENAI &&
+        !bodyToSend.prompt_cache_key &&
+        Array.isArray(bodyToSend.messages)
+      ) {
+        const { generatePromptCacheKey } = await import("@/lib/promptCache");
+        const cacheKey = generatePromptCacheKey(bodyToSend.messages);
+        if (cacheKey) {
+          bodyToSend = { ...bodyToSend, prompt_cache_key: cacheKey };
+        }
+      }
+
       const rawResult = await withRateLimit(provider, connectionId, modelToCall, () =>
         executor.execute({
           model: modelToCall,
@@ -1444,11 +1457,19 @@ export async function handleChatCore({
       const cachedTokens = toPositiveNumber(
         usage.cache_read_input_tokens ??
           usage.cached_tokens ??
-          ((usage as Record<string, unknown>).prompt_tokens_details as Record<string, unknown> | undefined)?.cached_tokens
+          (
+            (usage as Record<string, unknown>).prompt_tokens_details as
+              | Record<string, unknown>
+              | undefined
+          )?.cached_tokens
       );
       const cacheCreationTokens = toPositiveNumber(
         usage.cache_creation_input_tokens ??
-          ((usage as Record<string, unknown>).prompt_tokens_details as Record<string, unknown> | undefined)?.cache_creation_tokens
+          (
+            (usage as Record<string, unknown>).prompt_tokens_details as
+              | Record<string, unknown>
+              | undefined
+          )?.cache_creation_tokens
       );
 
       saveRequestUsage({
@@ -1604,11 +1625,19 @@ export async function handleChatCore({
       const cachedTokens = toPositiveNumber(
         streamUsage.cache_read_input_tokens ??
           streamUsage.cached_tokens ??
-          ((streamUsage as Record<string, unknown>).prompt_tokens_details as Record<string, unknown> | undefined)?.cached_tokens
+          (
+            (streamUsage as Record<string, unknown>).prompt_tokens_details as
+              | Record<string, unknown>
+              | undefined
+          )?.cached_tokens
       );
       const cacheCreationTokens = toPositiveNumber(
         streamUsage.cache_creation_input_tokens ??
-          ((streamUsage as Record<string, unknown>).prompt_tokens_details as Record<string, unknown> | undefined)?.cache_creation_tokens
+          (
+            (streamUsage as Record<string, unknown>).prompt_tokens_details as
+              | Record<string, unknown>
+              | undefined
+          )?.cache_creation_tokens
       );
 
       saveRequestUsage({
diff --git a/open-sse/translator/request/openai-to-gemini.ts b/open-sse/translator/request/openai-to-gemini.ts
index 4aa3bba95f..8d4d2b4047 100644
--- a/open-sse/translator/request/openai-to-gemini.ts
+++ b/open-sse/translator/request/openai-to-gemini.ts
@@ -52,6 +52,7 @@ type GeminiRequest = {
   safetySettings: unknown;
   systemInstruction?: GeminiContent;
   tools?: Array<{ functionDeclarations: GeminiFunctionDeclaration[] }>;
+  cachedContent?: string;
 };
 
 type CloudCodeEnvelope = {
@@ -82,6 +83,11 @@ function openaiToGeminiBase(model, body, stream) {
     safetySettings: DEFAULT_SAFETY_SETTINGS,
   };
 
+  // Preserve cachedContent if provided by client (for explicit Gemini caching)
+  if (body.cachedContent) {
+    result.cachedContent = body.cachedContent;
+  }
+
   // Generation config
   if (body.temperature !== undefined) {
     result.generationConfig.temperature = body.temperature;
diff --git a/src/app/(dashboard)/dashboard/settings/components/AppearanceTab.tsx b/src/app/(dashboard)/dashboard/settings/components/AppearanceTab.tsx
index 3c5d685530..bf173b8b4b 100644
--- a/src/app/(dashboard)/dashboard/settings/components/AppearanceTab.tsx
+++ b/src/app/(dashboard)/dashboard/settings/components/AppearanceTab.tsx
@@ -106,7 +106,10 @@ export default function AppearanceTab() {
     { id: "cyan", color: COLOR_THEMES.cyan, label: t("themeCyan") },
   ];
 
-  const sidebarSections = SIDEBAR_SECTIONS.map((section) => ({
+  const showDebug = settings.debugMode === true;
+  const sidebarSections = SIDEBAR_SECTIONS.filter(
+    (section) => section.visibility !== "debug" || showDebug
+  ).map((section) => ({
     ...section,
     title: getSidebarLabel(section.titleKey, section.titleFallback),
     items: section.items.map((item) => ({ ...item, label: tSidebar(item.i18nKey) })),
diff --git a/src/app/api/cache/entries/route.ts b/src/app/api/cache/entries/route.ts
index 26f30b02a9..97ff51ca9a 100644
--- a/src/app/api/cache/entries/route.ts
+++ b/src/app/api/cache/entries/route.ts
@@ -1,5 +1,6 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getDbInstance } from "@/lib/db/core";
+import { isAuthenticated } from "@/shared/utils/apiAuth";
 
 interface CacheEntry {
   id: string;
@@ -12,6 +13,10 @@ interface CacheEntry {
 }
 
 export async function GET(req: NextRequest) {
+  if (!(await isAuthenticated(req))) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+
   try {
     const { searchParams } = new URL(req.url);
     const page = Math.max(1, parseInt(searchParams.get("page") || "1", 10));
@@ -71,6 +76,10 @@ export async function GET(req: NextRequest) {
 }
 
 export async function DELETE(req: NextRequest) {
+  if (!(await isAuthenticated(req))) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+
   try {
     const { searchParams } = new URL(req.url);
     const signature = searchParams.get("signature");
diff --git a/src/app/api/cache/route.ts b/src/app/api/cache/route.ts
index d1bca53891..dd7364f929 100644
--- a/src/app/api/cache/route.ts
+++ b/src/app/api/cache/route.ts
@@ -9,15 +9,21 @@ import {
 } from "@/lib/semanticCache";
 import { getIdempotencyStats } from "@/lib/idempotencyLayer";
 import { getCacheMetrics, getCacheTrend } from "@/lib/db/settings";
+import { isAuthenticated } from "@/shared/utils/apiAuth";
 
 function errorMessage(error: unknown): string {
   return error instanceof Error ? error.message : String(error);
 }
 
 export async function GET(req: NextRequest) {
+  if (!(await isAuthenticated(req))) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+
   try {
     const { searchParams } = new URL(req.url);
-    const trendHours = parseInt(searchParams.get("trendHours") || "24", 10);
+    const rawHours = parseInt(searchParams.get("trendHours") || "24", 10);
+    const trendHours = Math.min(720, Math.max(1, Number.isNaN(rawHours) ? 24 : rawHours));
 
     const cacheStats = getCacheStats();
     const idempotencyStats = getIdempotencyStats();
@@ -36,6 +42,10 @@ export async function GET(req: NextRequest) {
 }
 
 export async function DELETE(req: NextRequest) {
+  if (!(await isAuthenticated(req))) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+
   try {
     const { searchParams } = new URL(req.url);
     const model = searchParams.get("model");
diff --git a/src/lib/db/settings.ts b/src/lib/db/settings.ts
index 333d71379f..5173e81e14 100644
--- a/src/lib/db/settings.ts
+++ b/src/lib/db/settings.ts
@@ -630,7 +630,7 @@ export async function getCacheMetrics() {
       totalCachedTokens: totalsRow?.totalCachedTokens || 0,
       totalCacheCreationTokens: totalsRow?.totalCacheCreationTokens || 0,
       tokensSaved,
-      estimatedCostSaved: 0, // Would need pricing data to calculate
+      estimatedCostSaved,
       byProvider,
       byStrategy,
       lastUpdated: new Date().toISOString(),
diff --git a/src/lib/promptCache/index.ts b/src/lib/promptCache/index.ts
index f4ee1fd501..2d1446f864 100644
--- a/src/lib/promptCache/index.ts
+++ b/src/lib/promptCache/index.ts
@@ -1 +1 @@
-export { analyzePrefix, shouldInjectCacheControl } from "./prefixAnalyzer";
+export { analyzePrefix, shouldInjectCacheControl, generatePromptCacheKey } from "./prefixAnalyzer";
diff --git a/src/lib/promptCache/prefixAnalyzer.ts b/src/lib/promptCache/prefixAnalyzer.ts
index 43f622c87f..6f8e86e12e 100644
--- a/src/lib/promptCache/prefixAnalyzer.ts
+++ b/src/lib/promptCache/prefixAnalyzer.ts
@@ -75,3 +75,11 @@ export function analyzePrefix(messages: Message[]): PrefixAnalysis {
 export function shouldInjectCacheControl(analysis: PrefixAnalysis, minTokens = 1024): boolean {
   return analysis.prefixTokens >= minTokens && analysis.confidence >= 0.7;
 }
+
+export function generatePromptCacheKey(messages: Message[]): string {
+  const analysis = analyzePrefix(messages);
+  if (analysis.prefixHash) {
+    return `omni-${analysis.prefixHash.slice(0, 32)}`;
+  }
+  return "";
+}
diff --git a/src/shared/components/Sidebar.tsx b/src/shared/components/Sidebar.tsx
index fb77a3017a..2eeb5a3b65 100644
--- a/src/shared/components/Sidebar.tsx
+++ b/src/shared/components/Sidebar.tsx
@@ -40,7 +40,7 @@ export default function Sidebar({
 
   useEffect(() => {
     const applySettings = (data) => {
-      setShowDebug(data?.enableRequestLogs === true);
+      setShowDebug(data?.debugMode === true);
       setHiddenSidebarItems(normalizeHiddenSidebarItems(data?.[HIDDEN_SIDEBAR_ITEMS_SETTING_KEY]));
     };
 
@@ -52,8 +52,8 @@ export default function Sidebar({
     const handleSettingsUpdated = (event: Event) => {
       const detail = (event as CustomEvent<Record<string, unknown>>).detail || {};
 
-      if ("enableRequestLogs" in detail) {
-        setShowDebug(detail.enableRequestLogs === true);
+      if ("debugMode" in detail) {
+        setShowDebug(detail.debugMode === true);
       }
 
       if (HIDDEN_SIDEBAR_ITEMS_SETTING_KEY in detail) {