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Spec drift: polymarket_us — market response missing minimumTradeQty field; required for partial-contract quantity validation (Jun 8 2026) #902

@realfishsam

Description

@realfishsam

Exchange

polymarket_us

Drift Type

changed_response

Severity

MEDIUM — without minimumTradeQty, PMXT cannot enforce minimum order size for partial-contract markets; orders below the minimum will be rejected by the API

Their Docs

Per the Polymarket US SDK changelog (v0.0.34), market objects now include minimumTradeQty (number) — the minimum tradeable quantity for partial-contract markets (e.g., 0.01 contracts). This is a required field for correct order validation starting June 8, 2026. Markets have varying minimum quantities based on their configuration.

Source: https://docs.polymarket.us/changelog (v0.0.34)

Our Cached Spec

core/src/exchanges/polymarket_us/normalizer.tsRealMarket interface does not include minimumTradeQty. The field is not read anywhere in normalizer.ts or index.ts.

File: core/src/exchanges/polymarket_us/normalizer.ts (RealMarket type / normalizeMarket)

callApi() References at Risk

Not applicable (uses polymarket-us SDK — this.client.markets.list({...}) at index.ts:158)

Hardcoded URL Bypasses

None

Impact

PMXT cannot tell callers what the minimum order size is for a given market. Any order submitted below minimumTradeQty will be rejected by the Polymarket US exchange. This affects all partial-contract markets.

Fix: Add minimumTradeQty to the RealMarket type and surface it in normalizeMarket(), mapping it to the normalized market's minOrderSize or orderPriceMinTickSize equivalent field.


Found by automated spec drift audit

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