diff --git a/craft/src/utils/tiny-invariant-shim.ts b/craft/src/utils/tiny-invariant-shim.ts
new file mode 100644
index 0000000..e9ec33b
--- /dev/null
+++ b/craft/src/utils/tiny-invariant-shim.ts
@@ -0,0 +1,17 @@
+/**
+ * Diagnostic shim for tiny-invariant. The prod tiny-invariant strips
+ * the failure message, so we lose the actual reason for any Craft.js
+ * Invariant. Aliasing tiny-invariant -> this shim restores it.
+ */
+export default function invariant(condition: unknown, message?: string | (() => string)): asserts condition {
+  if (condition) return;
+  const provided = typeof message === 'function' ? message() : message;
+  const value = provided ? `Invariant failed: ${provided}` : 'Invariant failed';
+  // Surface the message + stack to the console BEFORE throwing so even
+  // an uncaught throw leaves a trace we can read.
+  // eslint-disable-next-line no-console
+  console.error('[CRAFT INVARIANT]', value);
+  // eslint-disable-next-line no-console
+  console.error(new Error('stack-only').stack);
+  throw new Error(value);
+}
diff --git a/craft/vite.config.ts b/craft/vite.config.ts
index d35d5e4..d77c538 100644
--- a/craft/vite.config.ts
+++ b/craft/vite.config.ts
@@ -8,6 +8,9 @@ export default defineConfig({
   resolve: {
     alias: {
       '@': path.resolve(__dirname, './src'),
+      // Diagnostic: replace tiny-invariant with a shim that always logs the
+      // failure message (the upstream prod build strips it).
+      'tiny-invariant': path.resolve(__dirname, './src/utils/tiny-invariant-shim.ts'),
     },
   },
   build: {