204: Instruments That Cannot Fail

Overview

104 taught one person to check an agent's report: see a check go red, calibrate a search, and read an exit status with no pipe in the way. At project scale the checks are software in their own right, and an agent writes them too. They fail in the same shape as the reports they exist to check. A guard passes the input it was written to refuse. A gate says PASS over test rows it never read. A command overwrites the operator's files and lists them as created. A release verified on its staged copy installs binaries that cannot run.