buck-test.nu invokes several checks as ./scripts/<name>.nu, and nushell answers a file without the executable bit with Command `./scripts/buck-argv-roundtrip-check.nu` not found help: refers to a file that is not executable. Did you forget to set execute permissions? which reads like a MISSING SCRIPT rather than a missing mode. The full suite run died there, at the first such check it reached, having got as far as the static tier. EIGHTEEN files were in that state, every one of them a python-to-nushell port where the new file was written and the caller swapped but the mode never set. The ones invoked as `nu <script>` were unaffected, which is exactly why it went unnoticed: the checks I ran by hand all took that path. SO THE REFS CHECK NOW CHECKS THE MODE TOO. It already walks scripts/ to prove every scripts/<name> written down still exists; existing and being runnable are the same claim as far as a caller is concerned. Controlled both ways: with the bit removed from one file it names that file and fails, with it restored it passes. THE LESSON FOR THE REST OF THIS PORT: chmod +x is part of landing a port, not a detail, and the suite is the thing that says so. Running each check by hand proves the check works and proves nothing about how the suite calls it.