diff --git a/parts/packages.nix b/parts/packages.nix
index ef5f39a..61776ff 100644
--- a/parts/packages.nix
+++ b/parts/packages.nix
@@ -36,10 +36,14 @@
           ruff
         ];
         text = ''
-          if [ ! -x ./scripts/mcp-server/run-tests.sh ]; then
-            echo "Expected ./scripts/mcp-server/run-tests.sh to be executable from repo root." >&2
-            exit 1
-          fi
+          start_dir="$PWD"
+          while [ ! -x ./scripts/mcp-server/run-tests.sh ]; do
+            if [ "$PWD" = "/" ]; then
+              echo "Could not find executable scripts/mcp-server/run-tests.sh starting from $start_dir" >&2
+              exit 1
+            fi
+            cd ..
+          done
           exec bash ./scripts/mcp-server/run-tests.sh "$@"
         '';
       };