A table-driven codec for the small "named-enum" wire vocabularies the configuration boundary speaks: a queue or credential provider, the log format, the telemetry switch. Each is a fixed, finite set of wire names, historically hand-rolled as a parse \case, a render \case, and a separately maintained "(expected one of: …)" string -- three places kept in step by hand.

A WireVocab instance carries the vocabulary as one (value, name) table plus the human noun for the set. renderWire and parseWire are derived from it once and dispatched by type, so the rendered names, the parse, and the accepted-set message can no longer drift apart: there is a single list of names per type.

The vocabulary is keyed by type, which means one type speaks exactly one vocabulary. Where a type must be spoken two ways -- a credential provider is named differently as a mirror-target selector than as a per-mount field -- the second vocabulary is a newtype over the first with its own instance (see parseMirrorCredentialProvider).

The only contract is the round trip: for every value an instance's table names, parseWire (renderWire x) == Right x. It holds by construction, since both directions read the one wireTable. No algebraic laws are at stake, so this is deliberately not built on Ord, Semigroup, or Monoid.