The built-in family grid was calibrated for the synthetic demo streams (18/60
bars), where trend SMA 2-5 / MACD 2-4-3 are the only lengths that warm. Over real
M1 data those are noise — ~9000 exposure sign-flips per month, a strategy trading
the bid-ask wiggle, not a trend.
DataSource::strategy_lengths() makes the grid data-kind-dependent (like
wf_window_sizes): synthetic keeps {2,3}x{4,5} + MACD 2/4/3 (byte-unchanged); real
uses {50,100}x{200,400} trend SMAs + standard 12/26/9 MACD. Threaded through
sweep_family + sweep_over (the walk-forward in-sample sweep). Over real EURUSD the
monthly flip count drops from ~9000 to ~130-310 — a genuine trend cross.
This is a demo-strategy calibration patch (ledger C22 amendment notes it as such);
the real answer is project-authored strategies owning their own grid (C9), deferred
to the project-env work.
Verified: cargo test -p aura-cli (all green, synthetic byte-unchanged),
clippy -D warnings clean; real sweep probe shows ~130-310 flips/month.
refs #106
Brummel
99fd32b1f9