Fieldtest F9 surfaced that `design/models/0007-kernel-extensions.md`
lines 80 + 89 use `unit` as a value literal of type Unit. The
checker has no such literal — it treats the token as a Term::Var
lookup and emits `[unbound-var] main: unknown identifier: unit`.
An LLM author copy-pasting the worked example from the whitepaper
hits a hard wall the second they `ail check` it.
Two coherent resolutions: (a) ratify `unit` as the canonical
Unit-value literal (a one-line resolver change + a contract
update naming the literal), or (b) tighten the model to use the
existing canonical idiom. Picking (b) because:
- There is no existing language contract pinning `unit` as a
literal — the model was speaking aspirationally.
- The shipped surface already has a canonical no-op shape
(`(do io/print_str "")`); promoting that to the model is
cheaper than promoting a new keyword.
- The kernel-extension-mechanics milestone is closed — adding
a surface literal here would be unmotivated scope creep.
Both sites are if/match arms that produce Unit (i.e. they are
no-ops on the data side, used for control-flow exhaustiveness).
The replacement `(do io/print_str "")` produces Unit and is
already known-good per the kem_4_paramin_box_red.ail fieldtest
fixture. Future Series-milestone work may reach for a proper
unit-value literal; if it does, the brainstorm gate will weigh
adding it then.
Brummel
e094a71a3e