Tests the user's hypothesis: if no human reads the surface, lift the paren-
counting burden. Format 4 = annotated parens, every paren carries its nesting
depth. Discipline: the format has no ail parser, so the converter is round-trip
verified (parse-identity on known-good demos) before judging any model output.
Result: it helps. Plain Form-A 6/8 -> format 4 7/8 on the same ablation ladder.
The depth annotation cracks the bracket-balance wall that broke L4. At the
hardest level (L7 SMA) Qwen produced perfectly balanced brackets through the
deepest nesting AND correct SMA logic; the only remaining issue was a construct
quirk (it treats seq as variadic, but AILang seq is binary). Proof the blocks
were right: Qwen's exact logic with a manual binary-seq fix runs and emits the
exact expected SMA output.
Pushing further (format 4 + explicit seq-binary hint) fixed the seq nesting but
L7 still failed on two MODEL-behaviour limits, not encoding: it simplified the
logic, and fell into a closing-token repetition tail (hundreds of #0) ). The
tail is paren-driven, so the natural next test is a bracket-free format
(indent / keyword-delimited) with no closing token to loop on — a deliberate
next step needing its own verified converter. Synthesis in format-findings.md.
