Post-Only Rejection Needs a New Price Decision
By DX Research Group · · Execution mechanics
A moving quote can invalidate a maker-only order. Preserve the liquidity instruction and measure rejection handling separately from fill quality.
A maker-only instruction survives a price rejection. We would carry the liquidity restriction into recovery rather than treating the error as permission to cross the spread. Hyperliquid documents badAloPxRejected for a post-only price that would match immediately. That status answers why placement failed; it leaves the next price decision to the agent and its controls.
A rejected maker quote remains a maker decision
Illustrative case: a saved best ask is $100.10 and an agent proposes a post-only buy at $100.00. Before placement, the ask falls to $99.90. The intended price now crosses. Switching the order to aggressive execution at $100.00 changes both liquidity behavior and expected cost. Lowering the quote to $99.80 preserves maker-only intent but introduces a new waiting decision. Neither transformation follows from the rejected status alone.
Separate recovery from escalation
Record the submitted limit, quote timestamp, rejection timestamp and maker-only requirement. Refresh the quote and inventory before proposing another passive price. Keep aggressive fallback as a separate authorized policy with its own deadline and price bound. A test should move the ask across the submitted limit, then make the next quote stale. Expected handling is a new passive proposal or a visible wait, with maker-only authority retained through both states. Count rejected placements and eventual maker fills separately.
What the next turn receives
A useful denominator includes every maker placement attempt, including those that never rested. Report the fraction rejected because of moving prices and the fraction abandoned because the next quote was stale. Separately report the cost and fill coverage of authorized aggressive fallbacks. This makes a higher completion rate interpretable without disguising a change in liquidity policy.
Our execution and reconciliation framework provides the broader mandate-to-outcome trace. The state and memory contract explains how the verified result should enter the next decision. These notes narrow those published methods to one execution boundary; the worked amounts above are illustrative and the test is a proposed local fixture. The source inspected for the venue-specific statements is the official Hyperliquid order status documentation.