diff --git a/app.js b/app.js
index 21c5c222..12d67880 100644
--- a/app.js
+++ b/app.js
@@ -2006,6 +2006,30 @@ function setupControls() {
   
   document.getElementById('atlas-toggle-btn').addEventListener('click', openPortalAtlas);
   document.getElementById('atlas-close-btn').addEventListener('click', closePortalAtlas);
+
+  // Mnemosyne export/import (#1174)
+  document.getElementById('mnemosyne-export-btn').addEventListener('click', () => {
+    const result = SpatialMemory.exportToFile();
+    if (result) {
+      addChatMessage('system', 'Mnemosyne: Exported ' + result.count + ' memories to ' + result.filename);
+    }
+  });
+
+  document.getElementById('mnemosyne-import-btn').addEventListener('click', () => {
+    document.getElementById('mnemosyne-import-file').click();
+  });
+
+  document.getElementById('mnemosyne-import-file').addEventListener('change', async (e) => {
+    const file = e.target.files[0];
+    if (!file) return;
+    try {
+      const result = await SpatialMemory.importFromFile(file);
+      addChatMessage('system', 'Mnemosyne: Imported ' + result.count + ' of ' + result.total + ' memories');
+    } catch (err) {
+      addChatMessage('system', 'Mnemosyne: Import failed — ' + err.message);
+    }
+    e.target.value = '';
+  });
 }
 
 function sendChatMessage(overrideText = null) {
diff --git a/index.html b/index.html
index 54ada489..98b6fe23 100644
--- a/index.html
+++ b/index.html
@@ -233,6 +233,11 @@
         <div class="memory-meta-row"><span class="memory-meta-label">Time</span><span id="memory-panel-time">\u2014</span></div>
         <div class="memory-meta-row memory-meta-row--related"><span class="memory-meta-label">Related</span><span id="memory-panel-connections">\u2014</span></div>
       </div>
+      <div class="memory-panel-actions">
+        <button id="mnemosyne-export-btn" class="mnemosyne-action-btn" title="Export spatial memory to JSON">&#x2913; Export</button>
+        <button id="mnemosyne-import-btn" class="mnemosyne-action-btn" title="Import spatial memory from JSON">&#x2912; Import</button>
+        <input type="file" id="mnemosyne-import-file" accept=".json" style="display:none;">
+      </div>
     </div>
   </div>
 
diff --git a/nexus/components/spatial-memory.js b/nexus/components/spatial-memory.js
index ab3fdd87..87e3e770 100644
--- a/nexus/components/spatial-memory.js
+++ b/nexus/components/spatial-memory.js
@@ -652,11 +652,93 @@ const SpatialMemory = (() => {
     return _selectedId;
   }
 
+  // ─── FILE EXPORT ──────────────────────────────────────
+  function exportToFile() {
+    const index = exportIndex();
+    const json = JSON.stringify(index, null, 2);
+    const date = new Date().toISOString().slice(0, 10);
+    const filename = 'mnemosyne-export-' + date + '.json';
+
+    const blob = new Blob([json], { type: 'application/json' });
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = filename;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    URL.revokeObjectURL(url);
+
+    console.info('[Mnemosyne] Exported', index.memories.length, 'memories to', filename);
+    return { filename, count: index.memories.length };
+  }
+
+  // ─── FILE IMPORT ──────────────────────────────────────
+  function importFromFile(file) {
+    return new Promise((resolve, reject) => {
+      if (!file) {
+        reject(new Error('No file provided'));
+        return;
+      }
+
+      const reader = new FileReader();
+      reader.onload = function(e) {
+        try {
+          const data = JSON.parse(e.target.result);
+
+          // Schema validation
+          if (!data || typeof data !== 'object') {
+            reject(new Error('Invalid JSON: not an object'));
+            return;
+          }
+          if (typeof data.version !== 'number') {
+            reject(new Error('Invalid schema: missing version field'));
+            return;
+          }
+          if (data.version !== STORAGE_VERSION) {
+            reject(new Error('Version mismatch: got ' + data.version + ', expected ' + STORAGE_VERSION));
+            return;
+          }
+          if (!Array.isArray(data.memories)) {
+            reject(new Error('Invalid schema: memories is not an array'));
+            return;
+          }
+
+          // Validate each memory entry
+          for (let i = 0; i < data.memories.length; i++) {
+            const mem = data.memories[i];
+            if (!mem.id || typeof mem.id !== 'string') {
+              reject(new Error('Invalid memory at index ' + i + ': missing or invalid id'));
+              return;
+            }
+            if (!mem.category || typeof mem.category !== 'string') {
+              reject(new Error('Invalid memory "' + mem.id + '": missing category'));
+              return;
+            }
+          }
+
+          const count = importIndex(data);
+          saveToStorage();
+          console.info('[Mnemosyne] Imported', count, 'memories from file');
+          resolve({ count, total: data.memories.length });
+        } catch (parseErr) {
+          reject(new Error('Failed to parse JSON: ' + parseErr.message));
+        }
+      };
+
+      reader.onerror = function() {
+        reject(new Error('Failed to read file'));
+      };
+
+      reader.readAsText(file);
+    });
+  }
+
   return {
     init, placeMemory, removeMemory, update,
     getMemoryAtPosition, getRegionAtPosition, getMemoriesInRegion, getAllMemories,
     getCrystalMeshes, getMemoryFromMesh, highlightMemory, clearHighlight, getSelectedId,
-    exportIndex, importIndex, searchNearby, REGIONS,
+    exportIndex, importIndex, exportToFile, importFromFile, searchNearby, REGIONS,
     saveToStorage, loadFromStorage, clearStorage,
     runGravityLayout
   };
diff --git a/style.css b/style.css
index 2c3f70eb..ca208caa 100644
--- a/style.css
+++ b/style.css
@@ -1461,6 +1461,43 @@ canvas#nexus-canvas {
   gap: 2px;
 }
 
+/* ═══════════════════════════════════════════════════════
+   PROJECT MNEMOSYNE — EXPORT/IMPORT ACTIONS (#1174)
+═══════════════════════════════════════════════════════ */
+
+.memory-panel-actions {
+  display: flex;
+  gap: 8px;
+  margin-top: 10px;
+  padding-top: 10px;
+  border-top: 1px solid rgba(123, 92, 255, 0.15);
+}
+
+.mnemosyne-action-btn {
+  flex: 1;
+  padding: 6px 10px;
+  background: rgba(123, 92, 255, 0.12);
+  border: 1px solid rgba(123, 92, 255, 0.3);
+  border-radius: 6px;
+  color: #a08cff;
+  font-size: 11px;
+  font-family: monospace;
+  cursor: pointer;
+  transition: all 0.15s ease;
+  text-align: center;
+  white-space: nowrap;
+}
+
+.mnemosyne-action-btn:hover {
+  background: rgba(123, 92, 255, 0.25);
+  border-color: rgba(123, 92, 255, 0.6);
+  color: #c4b5ff;
+}
+
+.mnemosyne-action-btn:active {
+  transform: scale(0.96);
+}
+
 /* ═══════════════════════════════════════════════════════
    PROJECT MNEMOSYNE — SESSION ROOM HUD PANEL (#1171)
 ═══════════════════════════════════════════════════════ */