MiniMax M2.7 food-app run failed because the model emitted its full
subtask design wrapped in a single JSON array literal:
[
{ "id": "filterChips-root", "_parent": null, "type": "frame", … },
{ "id": "chip-1", "_parent": "filterChips-root", … },
…
]
The previous \`looksLikeJsonl\` gate only checked
\`startsWith('{')\` so this fell through to the DSL parser, which
tried to read \`[\` / \`{\` / \`}\` each on its own line as DSL
operations. Every line was rejected, the subtask returned empty,
the orchestrator retried with minimal skills, that timed out too,
and the user got a single-frame placeholder with one section
instead of the full screen.
Extended the gate to accept \`[\` as the leading character. The
shape signature stays the same (\`_parent\` or PenNode \`type\`
key inside the first 800 chars) — the bracket check just
disambiguates from real DSL. \`parseJsonlToTree\` already handles
both shapes via brace-counting (it scans for \`{...}\` blocks and
ignores surrounding \`[\`, \`]\`, and \`,\`), so the apply path
needed no changes.
Exported \`looksLikeJsonl\` for direct unit testing. 6 new tests
cover: pure JSONL match, JSON-array match (the M2.7 case),
array with leading whitespace, DSL-style assignment lines reject,
empty/non-bracketed reject, and bracketed-but-no-PenNode-keys
reject (so we don't reroute legit non-design array operations).
Verified by temporarily reverting the gate to just \`{\`: the two
new array tests correctly fail.
5214ace2fe