diff --git a/dashboard.html b/dashboard.html
index 45ef72c..98750d9 100644
--- a/dashboard.html
+++ b/dashboard.html
@@ -55,7 +55,13 @@
 </div>
 
 <div class="section">
-  <h2>Usage by Key</h2>
+  <div class="flex" style="justify-content: space-between; align-items: center;">
+    <h2 style="margin: 0;">Usage by Key</h2>
+    <label id="usage-scope-toggle" class="flex" style="display:none; gap: 0.4rem; font-size: 0.8rem; color: #94a3b8; cursor: pointer;">
+      <input type="checkbox" id="usage-show-all" style="cursor: pointer;">
+      <span>Show all keys</span>
+    </label>
+  </div>
   <table id="key-usage-table">
     <thead><tr><th>Key</th><th>Requests</th><th>OK</th><th>Err</th><th>Avg Time</th><th>Last Request</th></tr></thead>
     <tbody></tbody>
@@ -170,7 +176,8 @@ async function refreshStatus() {
 
 async function refreshUsage() {
   try {
-    const data = await api("/api/usage");
+    const showAll = localStorage.getItem("ocp_usage_show_all") === "1";
+    const data = await api(showAll ? "/api/usage?all=true" : "/api/usage");
     const tbody = document.querySelector("#key-usage-table tbody");
     tbody.innerHTML = (data.byKey || []).map(k => `
       <tr>
@@ -204,6 +211,8 @@ async function refreshKeys() {
   try {
     const data = await api("/api/keys");
     document.getElementById("key-mgmt-section").style.display = "";
+    // Admin-only "Show all keys" toggle for /api/usage scope.
+    document.getElementById("usage-scope-toggle").style.display = "flex";
     const tbody = document.querySelector("#keys-table tbody");
     tbody.innerHTML = (data.keys || []).map(k => `
       <tr>
@@ -240,6 +249,16 @@ async function refreshAll() {
   document.getElementById("refresh-indicator").textContent = `Updated ${new Date().toLocaleTimeString()}`;
 }
 
+// Wire "Show all keys" toggle (visibility gated to admin via refreshKeys()).
+(function setupUsageScopeToggle() {
+  const cb = document.getElementById("usage-show-all");
+  cb.checked = localStorage.getItem("ocp_usage_show_all") === "1";
+  cb.addEventListener("change", () => {
+    localStorage.setItem("ocp_usage_show_all", cb.checked ? "1" : "0");
+    refreshUsage();
+  });
+})();
+
 refreshAll();
 setInterval(refreshAll, 30000);
 </script>
diff --git a/server.mjs b/server.mjs
index 635c323..6e48a47 100644
--- a/server.mjs
+++ b/server.mjs
@@ -1672,14 +1672,45 @@ const server = createServer(async (req, res) => {
   }
 
   if (req.url?.startsWith("/api/usage") && req.method === "GET") {
-    if (!isAdmin) return jsonResponse(res, 403, { error: "Admin access required" });
+    // Least-privilege scope rules (security audit follow-up):
+    //   - non-admin authenticated key  → only own rows
+    //   - anonymous (PROXY_ANONYMOUS_KEY) → only "anonymous" rows; ?all=true ignored
+    //   - admin without ?all=true       → only own ("admin") rows
+    //   - admin with    ?all=true       → full byKey/recent (legacy behavior); audited
+    // Authenticated callers are required (anyone reaching here passed the auth gate above);
+    // remote+no-auth requests would have been rejected before this point.
     const url = new URL(req.url, `http://${BIND_ADDRESS}:${PORT}`);
     const since = url.searchParams.get("since");
     const until = url.searchParams.get("until");
+    const wantAll = url.searchParams.get("all") === "true";
+    const callerName = req._authKeyName;
+
+    // Anonymous callers may never opt into all-keys view, even if they pass ?all=true.
+    const isAnonCaller = callerName === "anonymous";
+    const fullScope = isAdmin && wantAll && !isAnonCaller;
+
+    // scopeName === null when fullScope is true (no filter); otherwise the key_name to filter by.
+    const scopeName = fullScope ? null : callerName;
+
+    if (fullScope) {
+      logEvent("info", "admin_usage_full_scope", { caller: callerName, ip: req.socket.remoteAddress || null });
+    }
+
+    const byKeyAll = getUsageByKey({ since, until });
+    const recentAll = getRecentUsage(Math.min(parseInt(url.searchParams.get("limit") || "50", 10), 500));
+    const timeline = getUsageTimeline({
+      keyName: scopeName || undefined,
+      hours: Math.min(parseInt(url.searchParams.get("hours") || "24", 10), 720),
+    });
+
+    const byKey = scopeName ? byKeyAll.filter((row) => row.key_name === scopeName) : byKeyAll;
+    const recent = scopeName ? recentAll.filter((row) => row.key_name === scopeName) : recentAll;
+
     return jsonResponse(res, 200, {
-      byKey: getUsageByKey({ since, until }),
-      timeline: getUsageTimeline({ hours: Math.min(parseInt(url.searchParams.get("hours") || "24", 10), 720) }),
-      recent: getRecentUsage(Math.min(parseInt(url.searchParams.get("limit") || "50", 10), 500)),
+      byKey,
+      timeline,
+      recent,
+      scope: { self: scopeName, all: fullScope },
     });
   }