User-approved draft from the 8.6-vs-9 string is dict forward-compat
requirement: a new definition key (candidate -choiceunavailable) for
choices that are recognised but not available in the current runtime -
displayed among the choices with their -choicelabels notes, participating
in prefix disambiguation via the shared choiceword_match resolver (so
abbreviations colliding with forward-version choices are ambiguous
everywhere), and rejected at parse with a tailored recognised-but-
unavailable message. Adoption by the tclcore string is model gives 8.6
users the dict class annotated and reserved (deliberately stricter than
real 8.6 for the di prefix - recorded as a user-sanctioned parity
exemption; full-word behaviour stays parity-true), plus an
i-string-is-dict documentation id generated from the static description.
Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com
Julian Noble