diff --git a/packages/romm-mcp/package.nix b/packages/romm-mcp/package.nix
index 76b5ca4..03f7cd8 100644
--- a/packages/romm-mcp/package.nix
+++ b/packages/romm-mcp/package.nix
@@ -22,6 +22,12 @@ buildNpmPackage rec {
 
   postPatch = ''
     cp ${./package-lock.json} package-lock.json
+
+    # romm_system action=scan was stubbed out client-side ("Scan endpoint removed in
+    # RomM 5.0"), but RomM 5.4 restored POST /api/tasks/scan, so the stub only blocks a
+    # working endpoint. Upstream publishes no sources in the npm tarball, so this patches
+    # the compiled dist/ directly; drop it once upstream restores runScan().
+    patch -p1 < ${./romm-mcp-scan.patch}
   '';
 
   # dist/*.js (tsc output) ships inside the npm tarball, so there is nothing to
diff --git a/packages/romm-mcp/romm-mcp-scan.patch b/packages/romm-mcp/romm-mcp-scan.patch
new file mode 100644
index 0000000..bf97983
--- /dev/null
+++ b/packages/romm-mcp/romm-mcp-scan.patch
@@ -0,0 +1,19 @@
+--- a/dist/client.js
++++ b/dist/client.js
+@@ -244,8 +244,14 @@
+     // NOTE: RomM 5.0 removed the POST /api/tasks/run endpoint.
+     // Scans are now managed through RQ workers and require background job management.
+     // Use the RomM web UI for scans and metadata updates.
+-    async runScan() {
+-        throw new Error("Scan endpoint removed in RomM 5.0. Use the RomM web UI to trigger library scans.");
++    async runScan(scanType = "quick") {
++        // RomM 5.4 restored library scans behind POST /api/tasks/scan (ScanPayload:
++        // type, platforms, platform_fs_slugs, roms_ids, apis). The stub above predates
++        // that. "quick" indexes new/changed files; "full" re-hashes the whole library.
++        return this.request("/api/tasks/scan", {
++            method: "POST",
++            body: JSON.stringify({ type: scanType }),
++        });
+     }
+     async runMetadataScan() {
+         throw new Error("Metadata scan endpoint removed in RomM 5.0. Use the RomM web UI to trigger metadata updates.");