The user-value chain, member by member

MCPJam's eval results travel as WIRE ENUMS: userValue, argumentMismatch, evaluatorErrorRateAboveMaximum. That is correct on the wire and useless without definitions, and the meanings are not derivable from the spellings. This is the definition of every member.

The story these values tell, in order: what was decided → how much was measured → where the chain broke → the evidence supporting that → who should look next. The decision summary says what the eval decided. The user-value chain explains how far value travelled, where it stopped, what evidence supports that claim, and who should investigate next.