Post-mortem NVIDIA 631181: one uncorroborated high-weight signal (legacy
Manifold 0.13 at weight 0.6) flipped a 0.845 market to 0.431 and lost.
With Manifold observational-only and macro signals gated behind
is_non_price, GNews (weight 1.5) is the only live signal able to move
politics markets 20-30 pp against the order-book consensus. This adds a
catastrophic fuse, not a fine calibration:
- apply_news_guardrail(): when |news_lo| >= NEWS_MATERIAL_LOGODDS_THRESHOLD
(0.10) and every other signal (fg, mom, btc_dom, mfld) is below it,
clamp the posterior to prior ± MAX_NEWS_ONLY_PROB_SHIFT (0.25). Any
corroborating material signal disables the clamp. Config via env
(NEWS_GUARDRAIL_ENABLED=true by default).
- edge_gross/edge_net computed from the clamped posterior; raw_final_prob
preserved in reasoning (persisted via trades.reasoning — no schema
migration) and in the NEWS_MATERIAL log line.
- guardrail_changed_trade_decision: raw edge crossed the regime gate but
the clamped edge no longer does (fuse prevented a trade). Note: with
the default 0.25 band the clamped edge_net is 0.21, above every regime
minimum, so the flag only fires with a tighter configured band.
- Observability gated on materiality: NEWS_MATERIAL per-market line and a
compact NEWS SUMMARY cycle line, only when with_news > 0 — no flood
from the ~145 news-less markets per cycle.
- 9 deterministic tests (extreme clamp, in-band passthrough, corroboration,
inclusive threshold, disabled, changed_decision).
No changes to NEWS_LOGODDS_WEIGHT, Manifold flags, edge thresholds,
sizing, payout, resolution, or historical trades.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
