# Diagnostic Confidence Cannot Exceed Sensor Honesty ## Claim A diagnostic tool cannot be more certain than the metadata its underlying device chooses to expose. <!-- atomicity: 1 idea ✓ --> ## Scope & conditions - This holds when software infers physical capability or authenticity from self-reported firmware, chips, headers, or telemetry. - Missing data may mean the sensor is absent, dishonest, unread, or simply wasn't queried under the current conditions. - Independent measurement can exceed metadata confidence when the relevant behavior can be tested directly. ## Evidence [[3. Resources/Readwise/Articles/WhatCable Know What Your USB-C Cable Can Really Do]] explains that e-marker data may be missing because macOS never queried the cable and that reported identifiers can be wrong, so anomaly flags mean “worth checking,” not proof of a counterfeit or faulty cable. ## Links - [[A Defense Experts Fail Is Not a Defense for Users]] — extends: a technically available signal doesn't protect users when its interpretation exceeds what ordinary evidence can support. - [[An Audit Trail Is Trustworthy Only When It Is a By-Product of the Work]] — contrasts: self-reported metadata is weaker than evidence emitted by the behavior being measured. - [[Cheap Inspection Collapses the Signal-Substance Gap]] — applies-in: direct load and transfer tests can check whether declared cable capability matches observed performance. - [[3. Resources/MOCs/Product & Startup Instincts MOC]] — applies-in: the MOC lists this note under Permanent Notes.