Tested the user's bracket-free ideas (indent, YAML) against the annotated-paren
result. Hypothesis was that removing the closing token removes the repetition
tail. The opposite held.
Instrument note (the watch-out paid off twice): a real YAML library auto-quotes
and gives *,-,true special meaning, which collides with the AILang operators —
Qwen wrote `- *` (multiply), a YAML alias marker, and the library crashed. That
is a measurement bug, not a model failure. Rebuilt with a hand-written literal
indent parser (atoms verbatim, no quoting); `- *` then round-trips fine.
With the instrument fixed, the result is monotone across four formats:
format 4 annotated parens 7/8 > plain Form-A parens 6/8 > yamlish indent 3/8
> YAML library 2/8.
More explicit structure marking helps this model; less hurts. Qwen's weakness
is structure-tracking at depth, and indentation makes it track the nesting
itself — as error-prone as matching parens but without the redundant cue. The
bracket-free surfaces fail EARLIER (L3/L4), before the L7 repetition ceiling is
even reached.
Lever for an LLM-authored language: redundant explicit structure (depth-
annotated brackets), not a lighter surface. Synthesis in format-findings.md;
raw ladders qwen-yaml.md (PyYAML, discarded) and qwen-yamlish.md (own parser).
