12. Two syllable capabilities, with the weaker one as the floor

Context

Syllable counting can be done from spelling, cheaply and approximately, or from a pronouncing dictionary, exactly and at the cost of shipping 3.6 MB of data. ADR 0004 forbids silent approximation across languages; the same argument applies within one.

A capability that no procedure requires is decoration, so declaring syllables.dictionary and having everything require it would leave syllables.heuristic inert — and a core-only install unable to check a haiku at all.

Decision

Both capabilities exist. Procedures declare syllables.heuristic, the weaker one, which every English pack satisfies. A pack that also declares syllables.dictionary answers the same calls more accurately; nothing branches on which is installed.

syllable_count returns (count, exact), and every syllabic report carries metrics["estimated_words"].

Consequences

The capability is a floor rather than a switch: installing denckring[en] improves existing procedures instead of enabling different ones. On Bashō's frog-pond haiku, core alone reports 13 estimated words; with the data package it reports zero.

This is not a silent fallback, because the estimate count is on every result. A caller needing certainty asserts it is zero, and a future procedure that cannot tolerate estimates may require syllables.dictionary outright, at which point a core-only install correctly raises MissingCapability.

The heuristic's agreement with the dictionary is measured by a test — currently 83.8% on a sample of 631 words — with an enforced floor, so a change that makes it worse fails the build rather than degrading quietly.