Per spec §6.2 per-side semantics:
cost_t = commission_per_rt × rt_ind[t]
+ half_spread[t] × |pos[t]| × side_ind[t]
+ ofi_lambda × |pos[t]| × |ofi[t]| × side_ind[t]
Commission charged at close; half-spread × |pos| at entry AND exit
(sums to one full spread per RT); OFI impact same per-side. Initial
λ=2.0e-4 in ISV[OFI_IMPACT_LAMBDA_INDEX=407] as Invariant-1 anchor
(constructor-write + FoldReset rewrite per feedback_isv_for_adaptive_bounds);
per-fold ISV refit may overwrite in later phases. Mean cost-per-bar
emitted to ISV[COST_PER_BAR_AVG_INDEX=408] (stateful kernel output;
FoldReset sentinel 0 + Pearl A first-observation bootstrap).
Same kernel reads LobBar fields from synthetic markets (Phase 2A) and
real fxcache LOB (prod) — dev/prod parity per Q3.
Phase 1.2 lands kernel + launcher + anchor seed + 2 registry entries
+ 2 dispatch arms only; consumer migration deferred to a follow-up
commit per feedback_no_partial_refactor (mirrors Phase 1.1 atomic
pattern). Oracle test cost_net_sharpe_round_trip_charges_full_spread
validates single round-trip cost = 2.00 / 10 bars = 0.20/bar with
mean_pnl_net = 0.80 on 1.69s RTX 3050 Ti (sm_86). Zero regressions
introduced (946 passed / 13 pre-existing failures, same as Task 1.1).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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