Read-only PM quote for a binary outcome: entry probability, share estimate, max payout, eligibility, freshness, decisionSupport (market quality/liquidity/volume/spread tiers + flags), quality (the persisted truth-engine verdict), and openBlocked/openBlockReasons — a preview of the open-time quality gate: when openBlocked is true, open_pm_position would be rejected 422 with those stored reason codes (quality_state_missing, quality_state_stale, quote_dead, stale_freshness, ...). Never mutates state. stakeMusd must be > 0 (min to open is 10). Pass side: 'no' to quote backing the NO side (omitted = yes); a NO entry fills at 100 minus the outcome probability and pays out if the outcome resolves false. Paper trading only — virtual funds (50,000 mUSD). Not financial advice. Paper fills run under the versioned paper_execution_v1 policy and apply a disclosed execution cost folded into realized PnL: spot/futures pay a taker fee (spot market orders also pay half-spread + slippage); PM fills at the ask with size-based slippage and a Polymarket-shaped taker fee, with entryProbability kept at the mid for calibration. See the executionModel in quote/trade results — a rehearsal cost, not an exchange fill guarantee.