Scottcjn · SageHaven · Aug 13, 2026
diff --git a/site/beacon/index.html b/site/beacon/index.html
@@ -70,6 +70,11 @@
     </div>
   </div>
 
+  <!-- Live agent rankings (Track C: agent leaderboard) -->
+  <aside class="agent-leaderboard" aria-label="Top Beacon agents" aria-live="polite">
+    <div class="leaderboard-empty">Loading agent activity...</div>
+  </aside>
+
   <!-- Controls hint (bottom-left) -->
   <div class="controls-hint">
     DRAG rotate | SCROLL zoom | RIGHT-DRAG pan<br>

diff --git a/site/beacon/leaderboard.mjs b/site/beacon/leaderboard.mjs
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: MIT
+
+const MAX_METRIC = 1_000_000_000;
+const DEFAULT_LIMIT = 10;
+const MAX_LIMIT = 50;
+
+function safeCount(value) {
+  const count = Number(value);
+  if (!Number.isFinite(count) || count <= 0) return 0;
+  return Math.min(MAX_METRIC, Math.floor(count));
+}
+
+function safeLimit(value) {
+  const limit = Number(value);
+  if (!Number.isFinite(limit) || limit <= 0) return DEFAULT_LIMIT;
+  return Math.min(MAX_LIMIT, Math.floor(limit));
+}
+
+function reputationFor(reputation, agentId) {
+  if (reputation instanceof Map) return reputation.get(agentId) || {};
+  if (!reputation || typeof reputation !== 'object') return {};
+  return reputation[agentId] || {};
+}
+
+function visibleContractCounts(contracts) {
+  const counts = new Map();
+  const seenByAgent = new Map();
+
+  for (const [index, contract] of (Array.isArray(contracts) ? contracts : []).entries()) {
+    if (!contract || typeof contract !== 'object') continue;
+    const contractKey = String(contract.id ?? `row-${index}`);
+    const participants = new Set([contract.from, contract.to].filter(value => (
+      typeof value === 'string' && value.length > 0
+    )));
+
+    for (const agentId of participants) {
+      if (!seenByAgent.has(agentId)) seenByAgent.set(agentId, new Set());
+      const seen = seenByAgent.get(agentId);
+      if (seen.has(contractKey)) continue;
+      seen.add(contractKey);
+      counts.set(agentId, (counts.get(agentId) || 0) + 1);
+    }
+  }
+
+  return counts;
+}
+
+function compareText(left, right) {
+  const a = String(left ?? '').toLowerCase();
+  const b = String(right ?? '').toLowerCase();
+  if (a < b) return -1;
+  if (a > b) return 1;
+  return 0;
+}
+
+/**
+ * Build a deterministic leaderboard without mutating live Atlas data.
+ *
+ * Contract totals use the larger of currently-visible relationships and the
+ * backend's completed-contract counter so historical work remains represented.
+ */
+export function buildAgentLeaderboard(
+  agents,
+  contracts,
+  reputation = {},
+  sortBy = 'beats',
+  limit = DEFAULT_LIMIT,
+) {
+  const contractCounts = visibleContractCounts(contracts);
+  const entries = [];
+  const seenAgentIds = new Set();
+
+  for (const agent of (Array.isArray(agents) ? agents : [])) {
+    if (!agent || typeof agent !== 'object') continue;
+    const id = typeof agent.id === 'string' ? agent.id : '';
+    if (!id || seenAgentIds.has(id)) continue;
+    seenAgentIds.add(id);
+
+    const rep = reputationFor(reputation, id);
+    const beats = safeCount(agent.beat_count);
+    const contractCount = Math.max(
+      safeCount(contractCounts.get(id)),
+      safeCount(rep.contracts_completed),
+    );
+
+    if (beats === 0 && contractCount === 0) continue;
+    entries.push({
+      id,
+      name: typeof agent.name === 'string' && agent.name.trim() ? agent.name.trim() : id,
+      beats,
+      contracts: contractCount,
+    });
+  }
+
+  const mode = sortBy === 'contracts' ? 'contracts' : 'beats';
+  const secondary = mode === 'beats' ? 'contracts' : 'beats';
+  entries.sort((a, b) => (
+    b[mode] - a[mode]
+    || b[secondary] - a[secondary]
+    || compareText(a.name, b.name)
+    || compareText(a.id, b.id)
+  ));
+
+  return entries.slice(0, safeLimit(limit));
+}
diff --git a/site/beacon/styles.css b/site/beacon/styles.css
@@ -90,6 +90,125 @@ html, body {
   color: var(--green);
 }
 
+/* --- Agent Leaderboard (left sidebar) --- */
+.agent-leaderboard {
+  position: fixed;
+  top: 150px;
+  left: 16px;
+  z-index: 50;
+  width: min(340px, calc(100vw - 32px));
+  max-height: calc(100vh - 220px);
+  display: flex;
+  flex-direction: column;
+  background: var(--bg-panel);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  box-shadow: 0 0 20px rgba(0, 255, 0, 0.05);
+  color: var(--text-body);
+  font-family: var(--font-mono);
+  pointer-events: auto;
+  overflow: hidden;
+}
+
+.leaderboard-header {
+  padding: 8px 10px;
+  background: rgba(0, 20, 0, 0.65);
+  border-bottom: 1px solid var(--border);
+}
+
+.leaderboard-title {
+  color: var(--amber);
+  font-family: var(--font-display);
+  font-size: 20px;
+  font-weight: 400;
+  letter-spacing: 1px;
+}
+
+.leaderboard-controls {
+  display: flex;
+  gap: 6px;
+  margin-top: 5px;
+}
+
+.leaderboard-mode {
+  padding: 2px 7px;
+  background: transparent;
+  border: 1px solid var(--border);
+  border-radius: 2px;
+  color: var(--text-dim);
+  font-family: var(--font-mono);
+  font-size: 10px;
+  cursor: pointer;
+}
+
+.leaderboard-mode[aria-pressed="true"] {
+  border-color: var(--amber-dim);
+  color: var(--amber);
+  background: rgba(255, 176, 0, 0.08);
+}
+
+.leaderboard-list {
+  min-height: 34px;
+  margin: 0;
+  padding: 0;
+  list-style: none;
+  overflow-y: auto;
+  scrollbar-width: thin;
+  scrollbar-color: var(--green-dim) transparent;
+}
+
+.leaderboard-item {
+  margin: 0;
+  padding: 0;
+}
+
+.leaderboard-row {
+  width: 100%;
+  display: grid;
+  grid-template-columns: 26px minmax(0, 1fr) 54px 54px;
+  gap: 5px;
+  align-items: center;
+  padding: 6px 9px;
+  background: transparent;
+  border: 0;
+  border-bottom: 1px solid rgba(26, 51, 26, 0.65);
+  color: var(--text-body);
+  font-family: var(--font-mono);
+  font-size: 11px;
+  text-align: left;
+  cursor: pointer;
+}
+
+.leaderboard-row:hover,
+.leaderboard-row:focus-visible {
+  background: rgba(51, 255, 51, 0.08);
+  color: var(--green);
+  outline: 1px solid var(--green-dim);
+  outline-offset: -1px;
+}
+
+.leaderboard-rank {
+  color: var(--amber);
+}
+
+.leaderboard-name {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.leaderboard-metric {
+  color: var(--text-dim);
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+}
+
+.leaderboard-empty {
+  padding: 10px;
+  color: var(--text-dim);
+  font-size: 11px;
+}
+
 /* --- Controls hint (bottom-left) --- */
 .controls-hint {
   position: fixed;
@@ -753,6 +872,17 @@ html, body {
   .hud-title { font-size: 22px; }
   .hud-stats { font-size: 14px; }
 
+  .agent-leaderboard {
+    top: 132px;
+    left: 8px;
+    width: min(330px, calc(100vw - 16px));
+    max-height: 36vh;
+  }
+
+  .leaderboard-row {
+    padding: 5px 7px;
+  }
+
   .controls-hint { display: none; }
 }