diff --git a/.quixos-subtree-source.json b/.quixos-subtree-source.json
index cb5a251..aa03317 100644
--- a/.quixos-subtree-source.json
+++ b/.quixos-subtree-source.json
@@ -1,7 +1,7 @@
 {
   "version": 1,
   "sourceRepo": "https://gitea-external.egads.tutti.syntaxblitz.net/quixos/quixos",
-  "sourceCommit": "d74b619314718cce6da10800d278d6bcc04b71fa",
+  "sourceCommit": "54e443af5dd963f1fa6f83f062f4943b46ad2535",
   "sourcePath": "quixos-instance/quixos-nix-helpers",
   "exportName": "quixos-nix-helpers",
   "mirrorRemote": "https://gitea-external.egads.tutti.syntaxblitz.net/quixos/quixos-nix-helpers.git"
diff --git a/install-dependencies.mjs b/install-dependencies.mjs
index 3481799..7ca1b37 100644
--- a/install-dependencies.mjs
+++ b/install-dependencies.mjs
@@ -36,6 +36,7 @@ async function packageDigest(directory) {
 /** Merge at package granularity: a scope such as @types is not a reserved package. */
 export async function installDependencies({ destination, application, defaults = [], selected = {}, reserved = [] }) {
   const entries = new Map();
+  const authored = new Set();
   for (const root of defaults) for (const [name, file] of await packages(root)) entries.set(name, file);
   for (const [name, file] of Object.entries(selected)) entries.set(name, file);
   if (application)
@@ -44,10 +45,17 @@ export async function installDependencies({ destination, application, defaults =
         const canonical = entries.get(name);
         if (!canonical || (await packageDigest(file)) !== (await packageDigest(canonical)))
           throw Error("Application dependencies cannot substitute selected React/client types or checked SDK: " + name);
-      } else entries.set(name, file);
+      } else {
+        entries.set(name, file);
+        authored.add(name);
+      }
     }
   for (const [name, file] of entries) {
     await fs.mkdir(path.dirname(path.join(destination, name)), { recursive: true });
-    await fs.symlink(file, path.join(destination, name));
+    // Application packages resolve siblings from this assembled node_modules.
+    // Keep SDK links canonical: copying those would duplicate branded types and
+    // React declarations from their own retained dependency closures.
+    if (authored.has(name)) await fs.cp(file, path.join(destination, name), { recursive: true, dereference: true });
+    else await fs.symlink(file, path.join(destination, name));
   }
 }