diff --git a/vite.config.ts b/vite.config.ts
index 134198a..fcc3c9d 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -37,14 +37,26 @@ export default defineConfig({
       "@binder": resolve(__dirname, "../evidence-binder/src"),
       "@work":   resolve(__dirname, "../citation-work/src/work"),
       "@app":    resolve(__dirname, "src/app"),
+      // Force a single pdfjs-dist instance across the umbrella and linked
+      // packages (evidence-source, citation-work, …). Each sibling has its
+      // own node_modules/pdfjs-dist path; without this alias Vite loads two
+      // module graphs, so main.tsx's GlobalWorkerOptions.workerSrc never
+      // reaches getDocument() inside evidence-source — upload fails with
+      // 'No "GlobalWorkerOptions.workerSrc" specified.'
+      "pdfjs-dist": resolve(__dirname, "node_modules/pdfjs-dist"),
     },
+    // Belt-and-braces for the same dual-instance problem (React too).
+    dedupe: ["pdfjs-dist", "react", "react-dom"],
   },
   server: {
     fs: {
-      // Allow Vite to serve /fixtures/pdfs/*.pdf from the project root.
+      // Allow Vite to serve /fixtures/pdfs/*.pdf from the project root,
+      // and to read linked sibling packages outside this repo root.
       allow: [
         resolve(__dirname),
         resolve(__dirname, "../citation-engine"),
+        resolve(__dirname, "../evidence-source"),
+        resolve(__dirname, "../evidence-anchor"),
         resolve(__dirname, "../evidence-binder"),
         resolve(__dirname, "../citation-work"),
       ],