Legacy fan-out writes <sweep-dir>/<cell>/summary.json (one cell per
Argo task). P6 batched flow writes <sweep-dir>/<cell>/sim_<variant>/
summary.json (one Argo task → run_batched_cell → harness with
variant_names → sim_<name>/ subdirs per spec §3.3).
The aggregator was looking only at <sweep-dir>/<cell>/summary.json,
so the realistic batched smoke completed the actual backtest fine
(2M events, 500k decisions, real artifacts written) but the
end-of-sweep aggregate step errored with "no cell directories with
summary.json".
Walk both layouts: directories containing summary.json directly are
flat cells (legacy); directories one level deeper that contain
summary.json are batched-cell variants. Cell labels become
"<cell>/<variant>" so the aggregate.parquet rows distinguish.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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