Get Neg Risk

Polymarket-compat GET /neg-risk/{token_id}.

Returns whether the market routes through Polymarket’s negative-risk contract — the REAL upstream flag, not a stub.

PM-compat P1 batch (eval 2026-06-10, pm-compat finding): this endpoint hardcoded false while polysim’s own /v1/book reported neg_risk: true for the same token (the book passes the upstream payload through). An SDK port branching on get_neg_risk() — e.g. to pick the neg-risk exchange adapter or filter mutually-exclusive event groups — got data that contradicted the book one call earlier. Single source now: the upstream CLOB book payload, with fallbacks.

Resolution cascade:

1. Live CLOB /book payload’s neg_risk bool (same source GET /v1/book serializes).
2. Last-known cached book (orderbook: / clob:book: Redis layers) when the live fetch blips.
3. Catalog classification off the market row’s tags/category (_classify_neg_risk) when no book is available at all.
4. 404 {"error": "market not found"} — PM’s live message verbatim (probed 2026-06-11) — when the token resolves to no known market.

Note: sim EXECUTION semantics don’t change for neg-risk markets — we report the real flag so routing/branching code behaves like it would against PM, but fills still settle per the standard binary flow (documented divergence).