diff --git a/scripts/buck-argv-roundtrip-check.nu b/scripts/buck-argv-roundtrip-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-bridge-generality-check.nu b/scripts/buck-bridge-generality-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-coverage.nu b/scripts/buck-coverage.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-darwin-rust-run.nu b/scripts/buck-darwin-rust-run.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-env-names-check.nu b/scripts/buck-env-names-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-env.nu b/scripts/buck-env.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-escape-check.nu b/scripts/buck-escape-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-escape-roots-check.nu b/scripts/buck-escape-roots-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-first-party-paths-check.nu b/scripts/buck-first-party-paths-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-hosttools-parity.nu b/scripts/buck-hosttools-parity.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-include-closure-check.nu b/scripts/buck-include-closure-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-labels-check.nu b/scripts/buck-labels-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-pin-patches-check.nu b/scripts/buck-pin-patches-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-pin-paths-check.nu b/scripts/buck-pin-paths-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-pin-rev-check.nu b/scripts/buck-pin-rev-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-prefix-consistency.nu b/scripts/buck-prefix-consistency.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-script-refs-check.nu b/scripts/buck-script-refs-check.nu
index 409977581..cc9e22cc4 100755
--- a/scripts/buck-script-refs-check.nu
+++ b/scripts/buck-script-refs-check.nu
@@ -103,10 +103,23 @@ def main [--scan: string = ""] {
         say $"   plus ($named | length) check\(s) named by ($driver)"
     }
 
-    if ($bad | is-empty) and ($missing_checks | is-empty) {
-        say "PASS: every scripts/<name> written down still exists"
+    # AND IT HAS TO BE RUNNABLE, not merely present. buck-test.nu invokes several checks as
+    # ./scripts/<name>.nu, and a file without the executable bit fails there with
+    # "Command not found ... refers to a file that is not executable", which reads like a
+    # missing script rather than a missing mode. EIGHTEEN of them were in that state after the
+    # python ports, and the suite died on the first one it reached.
+    let not_exec = (^find scripts -name "*.nu" ! -perm -u+x | complete | get stdout | lines
+        | where {|l| $l != "" } | sort)
+
+    if ($bad | is-empty) and ($missing_checks | is-empty) and ($not_exec | is-empty) {
+        say "PASS: every scripts/<name> written down still exists and is executable"
         exit 0
     }
+    if ($not_exec | is-not-empty) {
+        say $"FAIL: ($not_exec | length) nushell script\(s) are not executable, so a caller that"
+        say "      runs them by path gets a confusing not-found error:"
+        for f in $not_exec { say $"  ($f)" }
+    }
     for m in $missing_checks {
         say $"FAIL: ($driver) runs ($m), and neither scripts/($m).nu nor .sh is there"
     }
diff --git a/scripts/buck-src-normalise-check.nu b/scripts/buck-src-normalise-check.nu
old mode 100644
new mode 100755
diff --git a/scripts/buck-upstream-names-check.nu b/scripts/buck-upstream-names-check.nu
old mode 100644
new mode 100755