diff --git a/apps/mobile/lib/sharedSmoke.ts b/apps/mobile/lib/sharedSmoke.ts
new file mode 100644
index 0000000..c736362
--- /dev/null
+++ b/apps/mobile/lib/sharedSmoke.ts
@@ -0,0 +1,14 @@
+// Runtime canary import from @chat-app/shared. Phase 0's only goal here
+// is to prove that Metro can resolve the workspace package and that
+// nothing in shared/crypto pulls in an RN-incompatible module path.
+//
+// `import type` would be erased by the TypeScript compiler before
+// reaching Metro, so we deliberately import a runtime symbol —
+// `crypto.setCryptoBackend` — and stash it in an exported reference.
+// We never call it here; Phase 1's real adapter does that after
+// constructing a CryptoBackend wrapping react-native-libsodium.
+//
+// This file is deleted in Phase 1 once the real adapter lands.
+import { crypto } from '@chat-app/shared';
+
+export const sharedSmoke = { register: crypto.setCryptoBackend };