diff --git a/index.html b/index.html
index dc8594d..e5df22b 100644
--- a/index.html
+++ b/index.html
@@ -262,6 +262,7 @@ The light is on. The room is empty."
 
     <script src="js/data.js"></script>
     <script src="js/utils.js"></script>
+    <script src="js/state-export.js"></script>
     <script src="js/combat.js"></script>
     <script src="js/strategy.js"></script>
     <script src="js/sound.js"></script>
diff --git a/js/engine.js b/js/engine.js
index 8a4bd40..f09a6d8 100644
--- a/js/engine.js
+++ b/js/engine.js
@@ -230,6 +230,10 @@ function tick() {
         G.lastEventAt = G.tick;
     }
 
+    if (typeof StateExport !== 'undefined' && StateExport && typeof StateExport.onTickBoundary === 'function') {
+        StateExport.onTickBoundary(G);
+    }
+
     // Emergent mechanics: track resource state and check for emergent events
     if (typeof EmergentMechanics !== 'undefined' && window._emergent) {
         if (Math.floor(G.tick * 10) % 100 === 0) { // every ~10 seconds
diff --git a/js/state-export.js b/js/state-export.js
new file mode 100644
index 0000000..5a62ec5
--- /dev/null
+++ b/js/state-export.js
@@ -0,0 +1,118 @@
+(function (global) {
+  const STORE_KEY = 'compounding-intelligence:beacon-state';
+  const MAX_SNAPSHOTS = 300;
+
+  function _safeNumber(value, fallback = 0) {
+    return typeof value === 'number' && Number.isFinite(value) ? value : fallback;
+  }
+
+  function _tickKey(value) {
+    if (typeof value !== 'number' || !Number.isFinite(value)) return '0';
+    return value.toFixed(3);
+  }
+
+  function _resolveSink(explicitSink) {
+    if (explicitSink) return explicitSink;
+    return global.CompoundingIntelligence || null;
+  }
+
+  function _resolveStorage(explicitStorage) {
+    if (explicitStorage) return explicitStorage;
+    return typeof global.localStorage !== 'undefined' ? global.localStorage : null;
+  }
+
+  function buildSnapshot(gameState = {}) {
+    return {
+      source: 'the-beacon',
+      kind: 'idle_game_state',
+      timestamp: new Date().toISOString(),
+      tick: _safeNumber(gameState.tick, 0),
+      phase: _safeNumber(gameState.phase, 1),
+      trust: _safeNumber(gameState.trust, 0),
+      resources: {
+        code: _safeNumber(gameState.code, 0),
+        compute: _safeNumber(gameState.compute, 0),
+        knowledge: _safeNumber(gameState.knowledge, 0),
+        users: _safeNumber(gameState.users, 0),
+        impact: _safeNumber(gameState.impact, 0),
+        ops: _safeNumber(gameState.ops, 0),
+      },
+      project_progress: {
+        active: Array.isArray(gameState.activeProjects) ? [...gameState.activeProjects] : [],
+        completed: Array.isArray(gameState.completedProjects) ? [...gameState.completedProjects] : [],
+        active_count: Array.isArray(gameState.activeProjects) ? gameState.activeProjects.length : 0,
+        completed_count: Array.isArray(gameState.completedProjects) ? gameState.completedProjects.length : 0,
+      },
+    };
+  }
+
+  function readStore({ storage, storeKey = STORE_KEY } = {}) {
+    const resolved = _resolveStorage(storage);
+    if (!resolved) return [];
+
+    try {
+      const raw = resolved.getItem(storeKey);
+      if (!raw) return [];
+      const parsed = JSON.parse(raw);
+      return Array.isArray(parsed) ? parsed : [];
+    } catch (_) {
+      return [];
+    }
+  }
+
+  function writeStore(entries, { storage, storeKey = STORE_KEY } = {}) {
+    const resolved = _resolveStorage(storage);
+    if (!resolved) return false;
+    resolved.setItem(storeKey, JSON.stringify(entries));
+    return true;
+  }
+
+  function writeSnapshot(snapshot, { storage, storeKey = STORE_KEY, sink } = {}) {
+    const entries = readStore({ storage, storeKey });
+    entries.push(snapshot);
+    while (entries.length > MAX_SNAPSHOTS) entries.shift();
+    writeStore(entries, { storage, storeKey });
+
+    const resolvedSink = _resolveSink(sink);
+    if (resolvedSink && typeof resolvedSink.ingestSnapshot === 'function') {
+      resolvedSink.ingestSnapshot(snapshot);
+    }
+
+    if (typeof global.dispatchEvent === 'function' && typeof global.CustomEvent === 'function') {
+      global.dispatchEvent(new global.CustomEvent('compounding-intelligence:state-export', { detail: snapshot }));
+    }
+
+    return snapshot;
+  }
+
+  function onTickBoundary(gameState, options = {}) {
+    const snapshot = buildSnapshot(gameState);
+    const key = _tickKey(snapshot.tick);
+    if (onTickBoundary._lastTickKey === key) return null;
+    onTickBoundary._lastTickKey = key;
+    return writeSnapshot(snapshot, options);
+  }
+
+  function resetTickBoundary() {
+    onTickBoundary._lastTickKey = null;
+  }
+
+  resetTickBoundary();
+
+  const api = {
+    STORE_KEY,
+    MAX_SNAPSHOTS,
+    buildSnapshot,
+    readStore,
+    writeStore,
+    writeSnapshot,
+    onTickBoundary,
+    resetTickBoundary,
+  };
+
+  if (typeof module !== 'undefined' && module.exports) {
+    module.exports = api;
+  }
+
+  global.StateExport = api;
+})(typeof window !== 'undefined' ? window : globalThis);