diff --git a/packages/zotero-mcp/package.nix b/packages/zotero-mcp/package.nix
index d7042d5..e3aa5e3 100644
--- a/packages/zotero-mcp/package.nix
+++ b/packages/zotero-mcp/package.nix
@@ -93,28 +93,17 @@ python3Packages.buildPythonApplication rec {
     # anything needed at runtime must live in this list.
     pymupdf
     ebooklib
+    # Runtime deps for the semantic-search tools (upstream "semantic" extra).
+    # zotero_mcp.semantic_search imports chromadb unconditionally at module
+    # scope (embeddings/providers/__init__.py, chroma_client.py), so these are
+    # hard requirements, not truly optional at runtime.
+    chromadb
+    sentence-transformers
+    openai
+    google-genai
+    tiktoken
   ];
 
-  # Optional extras (semantic search, PDF, scite).
-  # NOTE: buildPythonApplication stores these in passthru only and does NOT
-  # install them; adding an extra here has no runtime effect.
-  optional-dependencies = with python3Packages; {
-    semantic = [
-      chromadb
-      sentence-transformers
-      openai
-      google-genai
-      tiktoken
-    ];
-    pdf = [
-      pymupdf
-      ebooklib
-    ];
-    scite = [
-      requests
-    ];
-  };
-
   pythonImportsCheck = [ "zotero_mcp" ];
 
   meta = with lib; {