diff --git a/.github/workflows/run_tests.yml b/.github/workflows/run_tests.yml
index 1b8f416baa..319c7290dd 100644
--- a/.github/workflows/run_tests.yml
+++ b/.github/workflows/run_tests.yml
@@ -76,11 +76,16 @@ jobs:
           FILE_CHANGED_PKGS=""
           for dir in $CHANGED_DIRS; do
             pkg=$(echo "$DIR_TO_PKG" | grep "^${dir}=" | cut -d= -f2 | head -1 || true)
+            # Only add directories that map to a real root-workspace package.
+            # Some directories (e.g. tooling/lints) belong to a separate workspace
+            # and are not root members, so they have no mapping here. Previously we
+            # fell back to the raw directory name, which fabricated a bogus package
+            # (e.g. "lints") and produced a nextest filter like rdeps(lints) that
+            # hard-errors ("operator didn't match any packages"). Skipping such
+            # directories leaves the package set empty, which falls through to the
+            # "run all tests" path below.
             if [ -n "$pkg" ]; then
               FILE_CHANGED_PKGS=$(printf '%s\n%s' "$FILE_CHANGED_PKGS" "$pkg")
-            else
-              # Fall back to directory name if no mapping found
-              FILE_CHANGED_PKGS=$(printf '%s\n%s' "$FILE_CHANGED_PKGS" "$dir")
             fi
           done
           FILE_CHANGED_PKGS=$(echo "$FILE_CHANGED_PKGS" | grep -v '^$' | sort -u || true)
diff --git a/tooling/xtask/src/tasks/workflows/run_tests.rs b/tooling/xtask/src/tasks/workflows/run_tests.rs
index 84dc669239..62043c545a 100644
--- a/tooling/xtask/src/tasks/workflows/run_tests.rs
+++ b/tooling/xtask/src/tasks/workflows/run_tests.rs
@@ -222,11 +222,16 @@ fn orchestrate_impl(rules: &[&PathCondition], target: OrchestrateTarget) -> Name
           FILE_CHANGED_PKGS=""
           for dir in $CHANGED_DIRS; do
             pkg=$(echo "$DIR_TO_PKG" | grep "^${dir}=" | cut -d= -f2 | head -1 || true)
+            # Only add directories that map to a real root-workspace package.
+            # Some directories (e.g. tooling/lints) belong to a separate workspace
+            # and are not root members, so they have no mapping here. Previously we
+            # fell back to the raw directory name, which fabricated a bogus package
+            # (e.g. "lints") and produced a nextest filter like rdeps(lints) that
+            # hard-errors ("operator didn't match any packages"). Skipping such
+            # directories leaves the package set empty, which falls through to the
+            # "run all tests" path below.
             if [ -n "$pkg" ]; then
               FILE_CHANGED_PKGS=$(printf '%s\n%s' "$FILE_CHANGED_PKGS" "$pkg")
-            else
-              # Fall back to directory name if no mapping found
-              FILE_CHANGED_PKGS=$(printf '%s\n%s' "$FILE_CHANGED_PKGS" "$dir")
             fi
           done
           FILE_CHANGED_PKGS=$(echo "$FILE_CHANGED_PKGS" | grep -v '^$' | sort -u || true)