A Signed AI Agent Receipt Can Still Be Wrong

Your AI agent returns a signed receipt: 0 defects found. The signature is valid. The receipt has not been altered. The agent was authorized to run the check. The result can still be wrong. Perhaps the scanner hit a rate limit and silently converted eleven failures into eleven empty results. Perhaps a watchdog inspected 8 machines and issued a conclusion about 68. Perhaps a database health check ran select 1 successfully while the application was failing because a required column did not exist. In every case, the software can produce a well-formed result. It can even sign that result correctly. What it cannot prove is that it measured the claim the business thinks it measured. That distinction is becoming one of the most important problems in agent infrastructure: authentic receipt != adequate measurement authorized action != correct conclusion zero findings != complete inspection A signature answers only part of the question Cryptographic signatures are valuable. They can prove who signed an object and whether its contents changed after signing. They do not prove: that the check actually ran that it reached the intended target that it measured the right population that the sample supports the claimed conclusion that exceptions were not converted into zeros that a passing control answered the business question This is the difference between provenance integrity and measurement integrity . Provenance integrity asks: Who made this statement, and was the statement altered? Measurement integrity asks: What was actually observed, how much of the target was covered, and is the conclusion justified by that observation? An agent work protocol needs both. Otherwise, a signature can turn uncertainty into durable false confidence. Three failures with the same shape This article grew out of a thoughtful comment from Heinrich Neb on the first article in this series. He described three incidents from one week. First, a harvesting tool scanned 16 public repositories. Five returned