diff --git a/src/container-runner.ts b/src/container-runner.ts
index 31efa96..dafa143 100644
--- a/src/container-runner.ts
+++ b/src/container-runner.ts
@@ -104,6 +104,16 @@ function buildVolumeMounts(
       containerPath: '/workspace/group',
       readonly: false,
     });
+
+    // Global memory directory — writable for main so it can update shared context
+    const globalDir = path.join(GROUPS_DIR, 'global');
+    if (fs.existsSync(globalDir)) {
+      mounts.push({
+        hostPath: globalDir,
+        containerPath: '/workspace/global',
+        readonly: false,
+      });
+    }
   } else {
     // Other groups only get their own folder
     mounts.push({