diff --git a/plugin/core/router-loader.ts b/plugin/core/router-loader.ts
index 4dd4279..1a515f3 100644
--- a/plugin/core/router-loader.ts
+++ b/plugin/core/router-loader.ts
@@ -35,7 +35,16 @@ export async function loadRouters(
   log: { info(msg: string): void; warn(msg: string): void }
 ): Promise<void> {
   const map = getRouterMap();
-  map.clear();
+  // Don't clear() — that would wipe externally-registered routers added
+  // by other plugins via __prismFacet.addRouter. Instead, track which
+  // routers came from the filesystem this run and remove only those
+  // that disappeared. External routers (filePath sentinel) are never
+  // touched here.
+  const FILE_SENTINEL_PREFIX = "<external:";
+  const fileRoutersBefore = new Set<string>();
+  for (const [name, r] of map.entries()) {
+    if (!r.filePath.startsWith(FILE_SENTINEL_PREFIX)) fileRoutersBefore.add(name);
+  }
 
   if (typeof _G[LOAD_COUNTER_KEY] !== "number") _G[LOAD_COUNTER_KEY] = 0;
   (_G[LOAD_COUNTER_KEY] as number)++;
@@ -48,9 +57,12 @@ export async function loadRouters(
     );
   } catch {
     log.warn(`[prism-facet] routers directory not found: ${routersDir}`);
+    // No file-based routers this run — drop any leftover file routers.
+    for (const name of fileRoutersBefore) map.delete(name);
     return;
   }
 
+  const seenThisRun = new Set<string>();
   for (const file of files) {
     const name = routerNameFromFile(file);
     const filePath = path.resolve(routersDir, file);
@@ -61,11 +73,17 @@ export async function loadRouters(
         continue;
       }
       map.set(name, { name, filePath, module: mod });
+      seenThisRun.add(name);
       log.info(`[prism-facet] router loaded: ${name}`);
     } catch (err) {
       log.warn(`[prism-facet] router ${name}: failed to load — ${String(err)}`);
     }
   }
+  // Drop file-based routers that disappeared between loads. Untouched
+  // routers stay.
+  for (const stale of fileRoutersBefore) {
+    if (!seenThisRun.has(stale)) map.delete(stale);
+  }
 }
 
 export function getRouters(): LoadedRouter[] {
diff --git a/scripts/install.mjs b/scripts/install.mjs
index 3723d91..e402a5d 100644
--- a/scripts/install.mjs
+++ b/scripts/install.mjs
@@ -130,6 +130,24 @@ function copyDirRecursive(src, dest, excludeExts = []) {
       fs.copyFileSync(srcPath, destPath);
     }
   }
+  // openclaw 2026.5+ refuses to load plugins whose files are owned by
+  // non-root ("suspicious ownership"). fs.copyFileSync preserves source
+  // ownership, so rsync/tar from a developer laptop (uid 1000) breaks
+  // the plugin on next gateway restart. Force chown to root when we
+  // can (root-only); silently skip otherwise (dev mode under
+  // unprivileged user — uid checks don't apply there).
+  try {
+    if (process.getuid && process.getuid() === 0) chownRecursive(dest);
+  } catch {}
+}
+
+function chownRecursive(dir) {
+  fs.chownSync(dir, 0, 0);
+  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+    const p = path.join(dir, entry.name);
+    if (entry.isDirectory()) chownRecursive(p);
+    else fs.chownSync(p, 0, 0);
+  }
 }
 
 switch (action) {